Elevated Prolactin Research Articles

The Stress-Induced Hyperprolactinemia Might Not be That Stress-Induced as Argued: Observational Case-Control Study

The mechanism behind prolactin (PRL) elevation in stress-induced hyperprolactinaemia (si-HP) in humans is unclear. This study aimed to investigate the effect of psychological stress and venous puncture (VP) pain on si-HP. The study included 91 individuals (nine males, 82 females) referred for HP. Anxiety levels were assessed using the Anxiety Sensitivity Index-3 (ASI-3) and the State-Trait Anxiety Inventory (STAI-1 and STAI-2), and visual scales were used to evaluate trypanophobia, nosocomephobia, and scanxiety. Serial PRL measurements (SPM) were performed with venous cannula (VC) at 0 minutes (min), 30 min, and 60 min for the first 32 patients and with the VP method at the same intervals for the following 59 patients. si-HP was defined as PRL levels at 60 min (PRL60min) decreasing to normal limits according to gender. There were 23 HP (-), 25 HP (+), and 19 si-HP individuals, as well as 24 with macroprolactinaemia. The frequency of si-HP in the VC group (n = 7/32) was similar to that in the VP group (12/59, p=0.9). The PRL0min and PRL60min levels of the VC group were similar to those of the VP group. Trypanophobia, nosocomephobia, scanxiety, ASI-3, STAI-1, and STAI-2 scale scores were similar between the si-HP group and other groups. Trypanophobia, nosocomephobia, scanxiety, ASI-3, STAI-1 and STAI-2 scales scores were not correlated with PRL0min, or PRL60min levels. Si-HP is independent of states momentary or trait anxiety, and phobias trypanophobia, nosocomephobia and scanxiety. In this context, the relevance of the nomenclature of si-HP is controversial.

Clinical characteristics of patients with granulomatous lobular mastitis associated with Corynebacterium parakroppenstedtii infection and drug sensitivity analysis of the isolated strains

BackgroundIt is presently considered that Corynebacterium especially Corynebacterium kroppenstedtii (CK) infection, is one of the important causes of granulomatous lobular mastitis (GLM). However, the pathogen of mastitis in the past two years has been identified as a newly discovered Corynebacterium. But it is unclear whether the pathogen associated with the occurrence of GLM is also this bacterium.MethodsGLM female patients with positive bacterial culture in pus specimens from February 2023 to February 2024 who were identified as CK infection by mass spectrometer were selected as the research objects in this study, and the clinical isolates were identified by 16S rDNA sequencing technology to identify the specific pathogen of GLM-related bacterial infection. Subsequently, the clinical characteristics of the patients were compared with those of GLM patients without bacterial infection during the same period, to explore the effect of this particular type of Corynebacterium infection on disease development in GLM patients. Finally, we tested the minimum inhibitory concentration (MIC) values of antibiotics when inhibiting these separation strains in vitro through the E-Test experiment, to evaluate their medicine sensitivity.ResultsA total of 31 GLM patients initially diagnosed with Corynebacterium kroppenstedtii (CK) infection via MALDI-TOF MS were enrolled in the study. However, subsequent 16S rDNA sequencing revealed that 28 isolates (90.32%) were actually identified as the newly recognized Corynebacterium parakroppenstedtii (CPK). This discovery challenges the conventional belief that CK is the primary pathogen of GLM, suggesting instead that CPK is the predominant pathogen associated with GLM bacterial infections. Comparative analysis of the clinical characteristics between the two groups revealed a significantly higher recurrence rate among CPK-infected GLM patients compared to those without CPK infection, along with elevated prolactin levels (P < 0.05). The sensitivity test results indicated high sensitivity of the isolates to vancomycin, linezolid, and rifampicin.ConclusionIn conclusion, this study highlights that Corynebacterium kroppenstedtii strains isolated from GLM specimens were Corynebacterium parakroppenstedtii, serving as the primary pathogen closely linked to GLM’s occurrence. CPK infection significantly increases the risk of recurrence in GLM patients, with elevated prolactin levels potentially playing a pivotal role in this process. In clinical antimicrobial treatment, antimicrobials other than penicillin and ciprofloxacin may be empirically administered when sensitivity test results are inconclusive.

A case report of adolescent lactation due to the drug blonanserin

BackgroundSecond-generation antipsychotic drugs are increasingly used to treat depressive disorders with psychotic symptoms. In addition to effectively managing psychotic symptoms, second-generation antipsychotics can also result in adverse drug reactions in patients, which should not be underestimated.Case presentationWe report the case of 14 years old unmarried female patient with depression. At first, she started with moping and gradually developed into self-injury and whispering. After antidepressant treatment combined with the second-generation antipsychotic drug blonanserin, the patient’s psychotic and depressive symptoms improved significantly, while the patient developed lactation, which stopped after the medication was changed.ConclusionsAlthough Blonanserin’s clinical trials have reported rare adverse reactions like elevated prolactin levels and even lactation, caution is still needed in clinical application of the drug. This case is expected to improve psychiatrists’ choice of antidepressant therapy in combination with antipsychotic drugs.

8024 A Case of Smoldering Clinically Silent Cushing’s Disease

Abstract Disclosure: C. Bheeman: None. I. Shafiq: None. Aggressive pituitary adenomas account for about 10% of all pituitary adenomas. These aggressive tumors are noted to have unusually rapid tumor growth rate despite optimal standard therapies including surgery, medical therapy and radiotherapy. We present a case of a 39-year-old female with no prior past medical history who initially presented with complaint of amenorrhea. She had reported she had not menstruated for the past 6 months. She also endorsed galactorrhea with nipple stimulation. A pituitary dedicated MRI revealed a pituitary adenoma measuring 2.5 x 1.7 x 1.7 cm. Hormonal work-up showed salivary cortisol on two consecutive nights that was 66 ng/dL and 52 ng/dL (reference range: 0 - 99 ng/dL) and a prolactin that was slightly elevated at 44.9 ng/mL (reference range: 4.8-23.3 ng/mL). This elevation in prolactin was thought to be due stalk effect and since her hypothalamus-pituitary-gonadal axis was suppressed, patient had a transsphenoidal resection of what was thought to be a nonfunctioning adenoma. However, the pathology of her tumor was significant for extensive ACTH staining and a Ki-67 of 11 - 15%. Her clinical course proved to be challenging as her tumor reoccurred multiple times and she eventually developed biochemical and clinical evidence of Cushing’s disease and had visual defects due to compression of the tumor on the optic nerves. This tumor was refractory to multiple surgeries, radiation treatment and chemotherapy. Through the presentation of this case, we aim to highlight the factors associated with aggressive pituitary adenomas, the current treatment guidelines and emerging medical therapies. Presentation: 6/1/2024

6469 Supplement Misadventures: A Case Of Acute Heart Failure, Cardiogenic Shock, And Hormonal Dysregulation Secondary To Surreptitious Use Of Multiple Hormonal Supplements

Abstract Disclosure: K.N. Grennan: None. S. Thota-Kammili: None. A.L. McKenna: None. C.G. Coyle: None. S.L. Samson: None. Introduction: Supplement misuse in the bodybuilding community is prevalent. With the availability of internet ordering and purchasing, patients have access to hormonal supplements without prescription or regulation. Here we present the case of a patient on self-administered hormonal supplements who presented in acute heart failure leading to cardiogenic shock in the setting of concurrent thyroid, adrenal, and gonadal axis dysfunction. Case Description: A 28-year-old male with no significant medical history was transferred to our hospital after presenting to an outside emergency room with dyspnea, cough, nausea, and a subjective fever. He developed acute hypoxic respiratory failure requiring intubation. Echocardiogram performed showed an ejection fraction (EF) of 10%. He was started on two vasopressors and methylprednisolone 1 g daily for two days, due to concern for myocarditis versus giant cell arteritis. Hormonal work-up showed TSH 0.02 mIU/L (normal range 0.3-4.2), free T4 0.4 ng/dL (0.9-1.7), total T3 48 ng/dL (80-200), FSH &amp;lt;0.3 IU/L (1.2-15.8), LH &amp;lt;0.2 IU/L (1.3-9.6), ACTH &amp;lt;5.0 pg/mL (7.2-63), cortisol 1.7 mcg/dL (2.5-12), estradiol 171 pg/mL (8.0-35), total testosterone 1730 ng/dL (240-950), and prolactin 47 ng/mL (4.0-15.2). He received 10 mg dexamethasone at the outside facility. A medication bag found by his family included online purchases of non-prescribed testosterone cypionate and enanthate, liothyronine, anastrozole, and clomiphene. None were medical grade. He was also taking the anabolic steroid clenbuterol for 3 days prior. Echocardiogram on day 3 of admission showed an improved EF of 36%. Cardiac magnetic resonance imaging (MRI) showed a papillary fibroelastoma and myocarditis. Patient was weaned off vasopressors and the ventilator. He was discharged on levothyroxine 50 mcg daily and hydrocortisone 10 mg twice daily for outpatient reassessment. Transesophageal echocardiogram confirmed diagnosis of papillary fibroelastoma. One month Endocrinology clinic follow-up showed no evidence of posterior pituitary, thyroid, or adrenal axis dysfunction or growth hormone excess, but he continued to have gonadal axis suppression with elevated prolactin and estradiol, the latter thought to be secondary to conversion from testosterone. Pituitary MRI showed no micro or macroadenoma. His EF recovered to 50%. He is pending surgical removal of the aortic valve fibroelastoma. Discussion: With hormonal supplements easily accessible online, it is important for physicians to counsel patients about the dangers of misuse. This case highlights a previously healthy 28-year-old man who presented in critical condition with cardiogenic shock and hypothalamic-pituitary axis dysfunction from supplements he purchased online. There should be targeted educational interventions regarding the harm of supplements aimed at the bodybuilding community to prevent similar cases. Presentation: 6/2/2024

7550 Case Report On Concurrent Metastases To The Pituitary And Adrenal From A Primary Breast Cancer

Abstract Disclosure: M.V. David-santos: None. M.C. Isidro: None. Background: Metastatic Cancer to the pituitary gland is a rare condition accounting for 0.5% of all pituitary tumors. It rarely manifests clinically and is often found incidentally. Endocrine dysfunction usually arise, with 38.4% of cases presenting with Diabetes Insipidus, while 37.7% as Panhypopituitarism. On the other hand, prevalence of adrenal metastases is at 0.5 to 3.8% with 43% occurring bilaterally. Primary adrenal insufficiency occurs at 12.4% among those with bilateral metastases. Case: A 32-year old Chinese woman was diagnosed with Stage 4 breast adenocarcinoma ER PR Her2 Neu positive with metastases to the axillary lymph nodes, bone and right adrenal in July 2021. She underwent chemotherapy with Paclitaxel and Trastuzumab then radical mastectomy of the left breast in April 2022.5 months post op, PET scan was done which showed a 11 x 18 x 21 mm pituitary mass. In light of the primary malignancy, lesion was considered a metastatic focus. At that time, patient did not exhibit any neurologic symptoms such as blurring of vision or headaches. No polyuria, polydipsia, nocturia, easy fatigability, nausea or vomiting. Physical examination findings were normal. A hormonal panel showed the following: elevated Prolactin at 150 ng/ml (NV 3-20), normal plasma ACTH IRMA 10 pg/ml (NV &amp;lt; 50 pg/ml), low 8AM plasma cortisol at 1.55 ug/dL (Ref 5- 25 ug/dL), TSH was low at 0.15iIU/ml (0.27-3.75) while FT4 was normal at 0.87 ng/dl (NV 0.68 - 2.56).ACTH stimulation showed low cortisol at the 30th minute and 1st hour post ACTH infusion. Serum sodium and urine Osmolality were both normal. The hyperprolactinemia was attributed to Stalk effect, while the decreased cortisol was considered as central adrenal insufficiency. She was then started on Prednisone 5mg tab daily. Repeat TSH and FT4 5 months after showed normal TSH at 1.209, low FT4 at 5.97 pmol/L (NV 9.01-19.05). She was started on Levothyroxine 50mcg daily for the central hypothyroidism.Repeat Cranial MRI 4 months post diagnosis of the pituitary mass showed increased in its size. An endoscopic transsphenoidal resection and biopsy of the pituitary mass showed metastatic carcinoma of the pituitary gland. Staining of the sellar tumor were compatible with a metastatic carcinoma of breast origin. Intensity-modulated radiation therapy (IMRT) at 400 gray was done for 5 fractions and Trastuzumab was continued. Cranial MRI done 6 months post IMRT showed decreasing size of the pituitary mass to its latest size of 6 x 9 x 13 mm as of November 2023. Latest Whole abdominal CT scan of the adrenals showed clearing of the right adrenal Nodule. Conclusion: Breast cancer may also metastasize to endocrine organs causing hormonal dysfunction. Although curative treatment is no longer the goal for Metastatic breast cancer, prolongation of the quality of life is an important aspect to consider. Hormonal work up, surveillance and hormonal replacement can help in attaining this goal. Presentation: 6/3/2024

6553 Remission of Cushing’s Disease on Day 6 Post Transsphenoidal Surgery

Abstract Disclosure: M.N. Abdou: None. H. Alhumaidi: None. Background: Current recommendations for steroids replacement in the immediate post-operative (post op) period after transsphenoidal surgery (TSS) for patients with Cushing’s Disease (CD) are heterogenous and can be misleading. Monitoring daily morning cortisol for 72 hours post TSS with replacing steroids only after detecting low morning cortisol or signs of adrenal insufficiency (AI) has been mentioned in several studies. While some studies recommend either empiric steroids replacement on discharge regardless of status of remission or longer hospital stay for closer cortisol monitoring, others recommended monitoring for 3-4 days and starting steroids on discharge only if morning cortisol was &amp;lt; 415 nmol/L. Case: 60 years old female with a history of type 2 diabetes mellitus, hypertension and dyslipidemia was referred for an evaluation of a pituitary macroadenoma. She had an incidental finding of a pituitary mass measuring 25 mm on a CT brain obtained after a fall 3 months prior to her current visit. MRI pituitary gland revealed a 25x23x22 mm suprasellar mass with cavernous sinus invasion. She reported weight gain and worsening of diabetes control over the 2 years prior to her presentation. On exam, weight was 80 kg, BMI 32.5, BP 110/69, vital signs were otherwise normal. She had central obesity, facial plethora, and frontal hair thinning. Hormonal workup showed elevated 1 mg dexamethasone suppression test: 341 nmol/L (&amp;lt;55). 24h UFC was also high 233 nmol/24 hours (38-208). Morning cortisol 15.5 mcg/dl (6-18) with ACTH 228 pg/ml (7.2-63.3). Prolactin 581 mIU/L (58-418). FSH and LH were at the premenopausal range. TSH, FT4, and IGF-1 were normal. HBA1C 8%. Results were consistent with CD with central hypogonadism and mild elevation of prolactin likely due to stalk effect. Patient was admitted to the hospital for TSS. She had no surgical complications, and no steroids were used to monitor remission. Daily morning cortisol was measured after the surgery, readings were (1631, 668, 469, 224, 318, 110 nmol/l) day 1-6 (D1-D6) post op. She was started on oral Hydrocortisone (HC) 15 mg in the morning and 10 mg in the afternoon on D6 post op after documentation of cortisol level of 110 nmol/l. She was vitally stable and had no signs of AI before starting steroids. 1 day after starting oral HC she developed hypotension and hyponatremia. IV HC 100 mg was given immediately followed by 50 mg every 6 hours. Blood pressure improved with stress dose steroids. She was discharged home on HC 20 mg three times daily, tapered to reach 15, 10 over a period of 2 weeks. Conclusion: We present a case of CD that had a nadir morning cortisol on D6 post op in whom a diagnosis of fatal AI would have been missed if recommendations from some studies were followed. This case highlights the importance of prolonged monitoring for adrenal insufficiency if steroids were not used after surgery for CD. Presentation: 6/1/2024

8524 Pituitary Hormone Dysregulation In Symptomatic Long COVID: A Multi-Center Observational Study

Abstract Disclosure: S.L. Sims: None. A. Labadzhyan: None. Z. Chen: None. S. Kim: None. J. Brathwaite: None. L. Cullen: None. M. Koga: None. U. Cheliadinova: None. V. Hwe: None. D. Gomez: None. C. Andriakos: None. T. Melnik: None. E. Puig-Wong: None. S. Whelan: None. S. Cheng: None. S. Joung: None. Z. Abelev: None. C. Le: None. R. Zabner: None. Y. Kawakami: None. T. Araki: Consulting Fee; Self; Chiesi. Objective: Pituitary hormone dysregulation has been reported in symptomatic long COVID, but it has not been rigorously studied. We conducted a multicenter observational cross-sectional study to assess pituitary hormone levels in long COVID patients and a longitudinal study to follow patients with abnormal results. Methods: Male and female adults with confirmed symptomatic long COVID were recruited from post COVID clinics at Mount Sinai in New York, Cedars-Sinai in Los Angeles, and the University of Minnesota, as well as nationwide physician referrals. Pituitary hormone levels were measured, and because fatigue is common in long COVID, patients completed the QoL-AGHDA survey. Those who exceeded pre-determined survey cutoffs or demonstrated any hormone abnormality were invited to the longitudinal study to repeat surveys and blood work every 3 months. A separate cohort with banked serum samples from before and 3, 6, and 9 months after subacute COVID was used as a comparator. Correlation analysis examined associations between QoL-AGHDA scores and pituitary hormone levels. Results: 246 patients were enrolled in the cross-sectional study after a median of 17.0 months (range, 1-39) since the most recent SARS-CoV2 infection prior to the onset of long COVID symptoms. 56% were enrolled in the longitudinal study due to a high questionnaire score and/or pituitary hormone abnormalities. Current mean follow-up period is 7.95 ± 3.2 months. Mildly elevated prolactin levels were most frequent, observed in 12.7% of patients (males 14.0%, females 12.2%). These patients presented post-COVID with galactorrhea, irregular menses, erectile dysfunction, and nonspecific symptoms of hyperprolactinemia. On follow-up, mild hyperprolactinemia tended to persist. Mildly low IGF1 levels (Z-score &amp;lt;-1.0) were observed in 9.0% of patients (males 6.3%, females 10.0%); on follow-up, IGF1 levels recovered in only 15% of these patients. 2.0% of the entire cohort showed transiently elevated IGF1 levels (Z-score &amp;gt;2.0). Low morning cortisol (&amp;lt;5.0 µg/dL) was observed in 3.3% of patients, but response to cosyntropin stimulation was normal. Mild secondary hypothyroidism was observed in 3.7% of all patients, and mild hypogonadism was observed in 7.8% of males. There was no correlation between QoL-AGHDA score and level of each pituitary hormone. After excluding pre-COVID hormone abnormalities in the post subacute COVID cohort, the rate of hyperprolactinemia was lower than that seen in the long COVID cohort (1% vs 12.7%). The rate of low IGF1 levels was higher in the subacute COVID cohort (22% vs 9.0), but unlike with long COVID, low IGF1 levels after subacute COVID recovered in 3-6 months. Conclusion: Abnormalities in pituitary hormone levels in symptomatic long COVID are frequent, with persistent hyperprolactinemia in &amp;gt;10%. Pituitary hormone screening may be important in patients with prolonged symptomatic long COVID. Presentation: 6/3/2024

6534 Schwannoma-Induced Hyperprolactinemia: A Rare Presentation Unveiled

Abstract Disclosure: G. Naronowicz: None. F.F. Foo: None. J. Cheng: None. R. Ong: None. S.W. Holland: None. K. Chalasani: None. Background: This case describes a rare presentation of a schwannoma manifesting with hyperprolactinemia. Case Description: A 37 year-old female with a past medical history including prolactinoma presented to our endocrine office to establish care. Prior to presentation, this patient had been diagnosed with a prolactinoma in 2015 via MRI. She was started on Cabergoline 0.5mg twice a week for treatment and continued this medication without any bothersome side effects. However, she began experiencing progressive dizziness, tinnitus, bilateral galactorrhea, and vision changes, prompting her to seek further intervention. The patient presented to our endocrine office in October 2017 for her initial visit. Due to ongoing symptoms, an MRI was done which revealed an adenoma vs hyperplasia of the pituitary gland. During this time her prolactin level was within normal limits, thus she continued her Cabergoline regimen. Soon thereafter, the patient was seen again in April 2018 with evidence of stable prolactin levels on Cabergoline treatment, although a repeat MRI showed a concern for a 1.2 cm mass in the left cerebellopontine angle extending to the right auditory canal. The patient underwent a follow-up consultation with a neurosurgeon; However given the unavailability of surgery at that time owing to insurance-related matters, a subsequent MRI was performed in August 2019 which revealed a vestibular schwannoma with no pituitary mass, and she ultimately underwent resection of this mass in February 2020. Throughout this period, the patient presented with a rise in prolactin levels (23.7 to 41.9 ng/mL). However, due to an asymptomatic state and the absence of concerning pituitary mass, the decision to be observed off Cabergoline therapy appeared to be the appropriate clinical course of action. Following the surgery, she was seen again in June 2020 with normalization of her prolactin levels without ongoing cabergoline treatment. We continue to follow this patient to present day for annual appointments and she continues to have normal prolactin levels. Conclusion: This report underlines the importance of a thorough and multidisciplinary approach in the assessment of elevated prolactin levels in light of a schwannoma. This also highlights the significance of continued surveillance and the value of repeat imaging. Exploring alternative diagnoses, such as Schwannoma, broadens the scope of etiologies, thus allowing a comprehensive approach for accurate diagnosis. Presentation: 6/1/2024

7422 Adipsic Diabetes Insipidus Following Pituitary Macroadenoma Resection

Abstract Disclosure: J. Chippior: None. L. Ghalib: None. A 44 year-old female with a PMH of primary hypothyroidism, and a pituitary macroadenoma that was lost to follow up, presented to the ED with a chief complaint of an acute headache and decreased visual acuity involving the right eye over the past year. Patient was found to have a large, homogenous suprasellar mass with the largest dimension measuring 6.3 cm in size, and causing displacement of the optic chiasm. Initial hormonal workup was most notable for elevated prolactin at 128 ng/ml (3.3-26.7 ng/ml), which was slightly lower than when it was previously measured 10 years ago. The patient was taken to the OR for transsphenoidal endoscopic partial resection, but within 24 hours of post-op, she developed hypernatremia at 153 mmol/dL (135-145 mmol/dL) that was suspected to be secondary to diabetes insipidus (DI). In addition, she also suffered several small strokes involving her right midbrain and basal ganglia. She required multiple doses of DDAVP throughout her stay and this was ultimately continued upon discharge. Unfortunately, as follow up MRI had shown residual tumor within the third ventricle, she returned for a 2nd resection but once again suffered additional post-operative complications. The patient experienced additional strokes involving the right frontal and parietal lobes, and her DI became more labile than before, with her serum sodium peaking at 172 mmol/dL. Despite such a high degree of hypernatremia, she did not demonstrate any signs of thirst or any desire to access free water, even after her post-stroke encephalopathy had largely resolved. With less than 100 severe cases documented over the past four decades, it was suspected that the patient had a rare form of DI known as “adipsic DI”. Osmoreceptors within the hypothalamus can trigger the release of ADH or stimulate thirst, with the former requiring a smaller change in serum osmolality to generate such a response. Pituitary surgery involves manipulation of the infundibulum and any inadvertent severing can prevent ADH’s ability to travel from the hypothalamus to the posterior pituitary, subsequently leading to DI. The majority of patients with post-op DI increase their free water intake and subsequently do not develop hypernatremia. Those with adipsic DI lack this compensatory mechanism which leads to the electrolyte disturbance, and carries a higher risk of morbidity and mortality than those with typical DI. Following her second surgery, our patient was discharged with DDAVP once again but this time with a higher dose and frequency. She’s had numerous hospital readmissions since then for altered mental status in the setting of hypernatremia as she still struggles to meet her free water intake and continuously relies on her family for reminders. Though her case is certainly not typical, it highlights the added complexity of managing adipsic DI as it relies not only on DDAVP replacement, but replicating what is supposed to be an innate behavior. Presentation: 6/3/2024

8155 Isolated Hypothalamic-Pituitary Langerhans' Cell Histiocytosis in Adult Patients

Abstract Disclosure: A. Vu: None. M. Aguilera: None. J. Shakil: None. R. Al-Ward: None. Introduction: Langerhans cell histiocytosis (LCH) is an infiltrative disease due to clonal proliferation of immature dendritic cells mainly affecting children and seen in adults in less than 30% of cases. It can present as localized or with systemic manifestations, with isolated hypothalamic-pituitary lesions being exceptionally rare. Our report adds to the limited published literature by presenting two cases of isolated hypothalamic-pituitary LCH diagnosed in adults. Furthermore, one of the cases reveals a rare association with papillary thyroid cancer (PTC). Case 1: 35-year-old woman with no past medical history presented with 4 year history of amenorrhea and weight gain and more recently, polyuria and polydipsia. Further investigations showed hypogonadotropic hypogonadism, central hypothyroidism, and mildly elevated prolactin. She couldn’t complete water deprivation test due to extreme thirst. A dedicated pituitary MRI showed marked infundibular enlargement, concerning for hypophysitis. An extensive workup including assessments for autoimmune etiology, sarcoidosis, infections, and low-grade tumors, did not identify a definitive etiology. A PET scan was obtained (to rule out LCH and Erdheim Chester disease), which showed increased uptake in the pituitary stalk. Due to otherwise negative workup, transsphenoidal biopsy of the pituitary lesion was done. Post-procedure, diabetes insipidus (DI) was diagnosed due to elevated sodium while fasting for the procedure. Tissue examination revealed increased histiocytes and lymphocytes, and a positive BRAF V600E mutation confirming LCH as the underlying diagnosis. Case 2: 26-year-old male with history of LCH limited to the skull, in remission for 8 years after chemotherapy, presented with 4-week history of polyuria, polydipsia and weight loss. A 24-hour urine collection resulted in 6.5L of urine. During water deprivation test, there was notable increase in serum sodium, serum osmolarity, and urine osmolarity. Initial pituitary MRI was normal, but subsequent imaging revealed the loss of the posterior pituitary bright spot. PET scan showed focal FDG avidity in the right lower thyroid lobe, confirmed on fine needle aspiration as PTC with BRAF mutation. He underwent total thyroidectomy and is currently receiving chemotherapy for LCH recurrence. Discussion: LCH is infrequent in adults, presenting with variable manifestations based on affected organs. In the multifocal form, the hypothalamic-pituitary axis is involved in 5-50% of cases. Our report describes two unique cases with only four other reported cases of isolated hypothalamic-pituitary axis LCH in adults. Central diabetes insipidus can be seen before the diagnosis or as the disease progresses. Pituitary biopsy, although invasive, should be considered when the diagnosis is not clear. The association of PTC with a BRAF mutation is extremely rare and has been reported. Presentation: 6/2/2024

8138 Pituitary Stalk Interruption Syndrome (PSIS) in a patient with Isolated Hypogonadotropic Hypogonadism

Abstract Disclosure: A. Thomson: None. R. Osman: None. Pituitary Stalk Interruption Syndrome in a Patient with Isolated Hypogonadotropic Hypogonadism Pituitary Stalk Interruption syndrome (PSIS) is a rare cause of hypopituitarism, characterized by a radiologic constellation of thin or interrupted pituitary stalk, hypoplasia, or aplasia of the anterior lobe and with the presence of an ectopic posterior pituitary (EPP). It is most commonly associated with isolated growth hormone deficiency (IGHD) and is often diagnosed in childhood. We present one case of a patient with isolated hypogonadotropic hypogonadism in adulthood, subsequently found to have an PSIS on MRI. A 45 year old male patient presented to our clinic with hypogonadism. He gradually started developing decreasing libido, fatigue, and loss of erections. He had normal puberty and childhood growth, and has fathered one child. He denied history of anosmia or visual symptoms. Subsequent hormonal testing showed: morning Total Testosterone: 145 ng/dl (normal 264-916 ng/dl), Free testosterone 1.5 pg/ml (normal 6.8-21.5 pg/ml), LH 1.1 mIU/ml (normal 1.7-8.6 mIU/ml) and FSH of 3.6 mIU/ml (normal 1.5-12.4 mIU/ml). Prolactin was minimally elevated at 21 ng/ml (normal 4.0 - 15.2 ng/ml). Thyroid, IGF-1, cortisol, and ferritin levels were within normal limits. Repeat levels showed similar findings. He denied ever taking any form of exogenous testosterone. His pituitary MRI revealed a small volume of anterior pituitary tissue, measuring 0.2cm x 0.7cm x 0.7cm, without discrete pituitary adenoma, a hypoplastic midline stalk measuring 1.3 mm in AP diameter (nl 2-3 mm), with a T1 hyperintense nodularity measuring 0.6cm x 0.4cm along the posterior aspect of the sella turcica consistent with EPP. No additional structural abnormality or any mass lesions were identified. He was subsequently started on replacement testosterone therapy and his symptoms resolved. PSIS usually presents in childhood with IGHD. Patients may have other pituitary hormone deficiencies and congenital central nervous system defects, although panhypopituitarism is rare. There have been reports in children with delayed puberty and isolated hypogonadotropic hypogonadism who have been found to have PSIS. Only one othercase of an adult female patient exhibiting hypogonadotropic hypogonadism as the only manifestation of PSIS has been documented in the literature. Our case highlights the potential for an adult male to present later in life with hypogonadotropic hypogonadism as a manifestation of PSIS. The marginally elevated prolactin level may be due to lack of inhibition of hypothalamic dopamine on lactotroph cells within the pituitary caused by the EPP, although it is doubtful that this has clinical significance. This is a rare presentation of PSIS, clinicians should be mindful ofthis radiological constellation and the potential for isolated hypogonadotropic hypogonadism presenting unusually in the adulthood. Presentation: 6/3/2024

8043 IgG4-related disease with isolated involvement of the pituitary gland: case report

Abstract Disclosure: J.M. Ramos: None. Female patient, 36 years old, presented to our service complaining of a headache lasting five weeks, mainly in the frontal and left periorbital region, radiating to the occipital region. The pain was intense and intermittent, lasting about 40 minutes. No nausea or vomiting was reported, but the patient experienced dizziness and double vision. During the symptomatic interview, the patient mentioned increased thirst and urinary volume. In her medical history, she denied comorbidities, with only frequent episodes of tension-type headaches. She had no continuous medication use and no known drug allergies. The patient had undergone two cesarean sections, with the last one in December 2021. On physical examination, she had horizontal binocular double vision in all three gazes to the left, accompanied by pain during eye movement. Increased facial sensitivity on the left in branches V1 and V2 was observed. The rest of the physical examination showed no abnormalities. Initial general laboratory tests were normal. Evaluation of pituitary function was mostly normal, except for slightly elevated prolactin. A cranial MRI revealed an expansive lesion with sellar and suprasellar components measuring 1.2x1.1x1.2cm. Additional imaging of the sella turcica showed an intra- and suprasellar expansive lesion, predominantly isointense on T1, hyperintense on T2, with discreetly heterogeneous enhancement with gadolinium. In consultation with the neuroradiology team, a hypointensity on T2 at the left margin of the pituitary was noted, suggesting an inflammatory etiology. Based on this, laboratory tests were conducted, and treatment with methylprednisolone 1g per day for 7 days was initiated. After treatment completion, the IgG4 level was found to be 146.7 mg/dL (upper limit of reference: 86 mg/dL). A follow-up MRI, five days after the steroid pulse therapy, showed a reduction in lesion size to 0.8 cm in the cranio-caudal dimension, with a preserved appearance of the optic chiasm. The patient experienced considerable symptom improvement and was discharged with oral corticosteroids and a scheduled initiation of rituximab. The patient meets criteria confirming the diagnosis of IgG4-related hypophysitis, a rare condition representing 30% of hypophysitis cases. Isolated pituitary involvement is even rarer, and its association with diabetes insipidus has been described. Treatment involves corticosteroids, and rituximab can be considered, especially in recurrent cases. Presentation: 6/3/2024

6619 An Unlikely Cause of Oligomenorrhea: Acromegaly Secondary to a Sparsely Granulated, Somatotroph-Lactotroph Adenoma

Abstract Disclosure: S.I. Alicea: None. Y. Wu: None. J. Marquez: None. C.S. Botero Suarez: None. M. Kinaan: None. Introduction: Acromegaly most commonly presents as a pituitary tumor that causes excessive production ofgrowth hormone (GH); and rarely due to excess of GHRH or ectopic production of GH. Approximately 15% of surgically removed pituitary adenomas represent GH-producing neoplasms, and about 5% are bihormonal, secreting both GH and prolactin (PRL). We present a case of an unexpected presentation of oligomenorrhea which ended up with the diagnosis of acromegaly secondary to plurihormonal mixed somatotroph-lactotroph sparsely granulated adenoma. Case Description A 32-year-old female with history of prediabetes was referred to our clinic by her gynecologistfor evaluation of oligomenorrhea which was initially attributed to polycystic ovarian syndrome.She reported menarche at age 10 and has experienced irregular menses and periods of amenorrhea over the years. Physical exam revealed macroglossia, a widened thickened nose, acanthosis nigricans in the neck skin folds, facial hair thickening, and significant thickening of all fingers, toes and soft tissues. Given physical exam findings, we evaluated the patient for acromegaly and lab testing revealed markedly high IGF I, mildly elevated prolactin, and hemoglobin A1C of 5.7%. An MRI of the brain with IV contrast revealed a heterogeneously enhancing pituitary macroadenoma measuring 2.9 x 2.9 x 2.2 cm with suprasellar extension resulting in mass effect on the optic chiasm without definite cavernous sinus extension. She was started on Cabergoline 0.5mg twice weekly temporarily and underwent pituitary transsphenoidal resection. Pathology results revealed tumor cells that were positive for Chromogranin and Cam5.2. About 10% of cells showed immunoreactivity for Prolactin and negative for TSH, ACTH, FSH, LH and immunostains. There was also weak focal (about 2%) immunoreactivity for GH. Occasional mitotic figures were present. The MIB-1 proliferation index was 3%. The reticulin stain demonstrates loss of acinar architecture, supporting the diagnosis. Aside from transient sodium fluctuations consistent with triphasic response, she had no long-lasting postoperative complications. One month after her surgery, her IGF I level and hemoglobin A1C are trending down and she reports symptomatic relief. She continues follow up in our clinic. Discussion This patient has acromegaly secondary to a mixed somatotroph-lactotroph sparsely granulated adenoma. Sparsely granulated adenomas are more common in younger populations, can be more aggressive, and are less responsive to somatostatin analogs. Early detection and treatment is imperative in the prevention of complications secondary to the disease. Our case will closely examine the differences in the clinical, prognostic, and pathologic features of sparsely- vs. densely granulated adenomas. We will also discuss the effects of acromegaly on gonadal function. Presentation: 6/1/2024

6823 A Puzzling Case: Complete Regression of Pituitary Macroadenoma

Abstract Disclosure: N.T. Mazengia: None. D.R. Vangipuram: None. S.K. Majumdar: None. Introduction: The natural course of nonfunctioning pituitary macroadenomas remains poorly understood, largely because the majority are surgically treated [1]. There are a few case reports describing the spontaneous regression of nonfunctioning pituitary macroadenomas. Here we describe a case of pituitary macroadenoma which completely regressed following childbirth and two months of cabergoline therapy. Case Presentation: A 25-year-old female presented with bilateral nipple discharge and persistently elevated prolactin levels ranging from 31µg/liter to 45.9 µg/liter (NV &amp;lt;25 µg/L). She did not have any signs and symptoms of hypo or hypersecretion of the pituitary hormones. All her pituitary hormone levels were within normal range. Initial MRI revealed a pituitary mass measuring 9x13x9mm (AP, TR, CC). Given her lack of symptoms, the decision was made to follow up without any intervention. A repeat MRI after one year showed the size of the mass to be 11x13x11mm. Two years after her initial diagnosis, the patient had a spontaneous pregnancy, during which she remained asymptomatic with normal pituitary hormone levels. She had Cesarean delivery at term with no complication. She was lost to follow-up for about two years after childbirth then presented with breast discomfort and galactorrhea at which time, she was started on cabergoline. A subsequent MRI done two months after the start of cabergoline showed asymmetric fullness of the pituitary gland on the right with no discrete measurable lesion. Conclusion: We currently lack a comprehensive explanation for the regression observed in our patient. Silent ischemia may have played a role, particularly considering the natural increase in pituitary gland size during pregnancy. We are not sure if the regression can be solely attributed to the two months of cabergoline treatment. In asymptomatic patients diagnosed with nonfunctioning pituitary macroadenoma, tumor regression can potentially occur through either a "wait and watch" strategy or medical management using dopamine agonists, specifically cabergoline. However, the use of cabergoline as a primary treatment for asymptomatic nonfunctioning pituitary adenoma warrants further investigation. This is especially crucial given that, in most cases, nonfunctioning pituitary macroadenomas tend to increase in size during follow-up without any intervention.

7606 Partial Xp Duplication and Xq Deletion in a Patient with Premature Ovarian Failure: A Rare Case Report

Abstract Disclosure: A. Pataco: None. C.S. Moniz: None. C. Chaves: None. R. Medeiros: None. M. Ponte: None. B.D. Pereira: None. J. Anselmo: None. I. Sousa: None. Premature ovarian failure (POF) is a heterogeneous condition characterized by the cessation of ovarian function leading to amenorrhea before age 40. While the etiology of POF is diverse, the majority of cases are idiopathic, with a likely genetic basis. Xq abnormalities are commonly linked to POF, whereas Xp abnormalities are rare and infrequently reported.We describe a case of a 30-year-old woman with a personal history of depression, presenting to the Endocrinology department with an 8-month history of amenorrhea. Notably, her menstrual cycles had been irregular since menarche. Previously, a gynecological assessment led to the initiation of bromocriptine 5 mg/day for suspected microprolactinoma, indicated by symptoms of galactorrhea, elevated prolactin levels (112 ng/mL; Normal: 5.18-26.53), and a pituitary MRI showing a 3.5mm microadenoma. It is important to note her concurrent use of risperidone, sertraline, and lorazepam at that time.In the first evaluation at the Endocrinology department, the patient reported amenorrhea and denied galactorrhea. The physical examination was unremarkable with no evidence of hirsutism. The blood tests indicated hypergonadotropic hypogonadism, low levels of prolactin and Anti-Müllerian hormone: FSH 17 mIU/mL (Normal: 3.03-8.08), LH 8.30 mIU/mL (Normal: 1.80-11.78), 17-Beta Estradiol 11 pg/mL (Normal: 21-251), Total testosterone 20.1 ng/dL (Normal: 7.21-79.31), TSH 1.84 uIU/mL (Normal: 0.35-4.94), T4L 1.06 ng/dL (Normal: 0.70-1.48), PRL 1.8 ng/mL (Normal: 5.18-26.53), ACTH 21 pg/mL (Normal: 7.2-63.3), Cortisol 11.5 ug/dL (Normal: 3.7-19.4), IGF-1 130.2 ng/mL (Normal: 177-382), Anti-Müllerian hormone &amp;lt;0.1 ng/mL (Normal: 0.3-11.2).A diagnosis of premature ovarian failure was established. Bromocriptine was discontinued, and the hyperprolactinemia was attributed to the iatrogenic effects of her medications. A pelvic ultrasound showed no abnormalities. Cytogenetic analysis revealed an abnormal karyotype: 46 chromosomes with one X chromosome showing an anomalous configuration—partial deletion of the long arm and partial duplication of the short arm [duplication X(p22.33p11.23) with over 100 genes and deletion X(q24q28) including the FMR1 gene].The patient started hormone replacement therapy with estradiol valerate and medroxyprogesterone acetate, achieving regular menstruation thereafter. Literature review reveals that POF cases involving both partial Xp duplication and partial Xq deletion are exceedingly rare (only 6 reported cases). Genetic counseling is recommended for these patients, particularly for those considering parenthood. It is also advisable to assess the chromosomal alteration in parents to determine if the change is inherited and to evaluate the risk to other family members. Presentation: 6/2/2024

7883 Atypical Presentation of Macroprolactinoma: Discordantly Low Serum Prolactin and Therapeutic Challenges

Abstract Disclosure: S. Hossain: None. M.S. Hossain: None. B. Gautam: None. S.C. Kumar: None. H. Liao: None. D.S. Rosenthal: None. Introduction: Pituitary tumors are categorized as microadenomas (&amp;lt;1 cm) and macroadenomas (&amp;gt;1 cm) with prolactinomas being one of the most common causes. The mean prevalence of prolactinomas is 10 per 100,000 in men and 30 per 100,000 in women. Serum prolactin levels corresponds to the size of the prolactinoma and any discrepancy should be treated with caution as that may indicate co-existence of pluripotent cells. We present a patient who presented with visual field defect and headaches, found to have a pituitary macroadenoma with discordantly low serum prolactin level compared to the size of adenoma, prompting a change in the treatment course. Case Presentation: A 42 year old male with no past medical history was seen as an endocrinology consult requested by neurosurgery for frequent headaches and visual problems for 1 year. Vital signs were normal, with negative orthostatic drop of blood pressure. He had prominent bitemporal hemianopsia confirmed by formal visual field testing by Ophthalmology. No galactorrhea or features suggestive of acromegaly or hyperthyroidism. He complained of erectile dysfunction but appeared to have normal male secondary sexual characteristics. MRI of brain showed a suprasellar mass measuring 3.8 x 2.6 x 2.2 cm with mass effect on the optic chiasm, hypothalamus with extension and infiltration into the right cavernous sinus. Lab results showed elevated prolactin of 1343.5 ng/ml confirmed by serial dilution, low serum testosterone level of 134 ng/dl and inappropriately normal FSH and LH. Complete blood counts, comprehensive metabolic panel, TFT, ACTH, cortisol and IGF-1 were normal. Patient was started on bromocriptine and he noticed improvement in his field of vision and acuity within one week of starting therapy. He continued to show sustained improvement in vision and resolution of his headaches at the one-month mark. MRI 2 months from starting bromocriptine showed modest reduction in size of the tumor to 2.1 x 2.3 x 2.4 cm with continued mass effect on the optic chiasm. Prolactin level decreased to 69.3 ng/ml. Therefore, although there was some improvement in visual fields, surgical resection was recommended to alleviate the mass effect on the optic chiasm. Conclusion: Our case highlights the significance of identifying discrepancies between the size of a prolactinoma and serum prolactin levels. Expected prolactin level from a prolactinoma similar in size to our case would be &amp;gt;3000 ng/ml when ours was 1343.5ng/ml. Despite undergoing treatment and lowering of prolactin levels our patient's pituitary adenoma did not significantly reduce in size after two months of treatment with bromocriptine and the mass continued to exert pressure on the optic chiasm. This suggests possible presence of pluripotent cells in addition to prolactin-producing cells within the tumor. The recommended course of action was surgical resection of the mass. Presentation: 6/1/2024

7013 An Inpatient Perspective: Hyperprolactinemia and Granulomatous Mastitis

Abstract Disclosure: A. Le: None. J. Wade: None. K. Martz: None. D. Girgis: None. M. Shahlapour: None. M.H. Horani: None. Introduction: Mastitis is a highly prevalent condition impacting thousands of women every year. Most commonly associated with lactation, mastitis is estimated to impact 2-20% of lactating women particularly in the first 4-6 weeks of breastfeeding (Wilson et al., 2020). The majority of cases are associated with bacterial infection with Staphylococcus aureus precipitated by nipple trauma and hyperlactation in the setting of genetic predispositions and disturbances to the human milk microbiota (Fernández et al., 2020). In rare cases, mastitis is seen outside of the context of lactation. One cause of non-lactational mastitis is idiopathic granulomatous mastitis (IGM). The pathogenesis of IGM is poorly understood, but there has been a rare association between IGM and hyperprolactinemia reported in the literature (Nikolaev et al., 2016). Case Presentation: In January 2022, A 20 year old female with past medical history of type 2 diabetes mellitus and hypertension, initially presented to the emergency department with complaints of headache. Patient’s history is notable for two years of amenorrhea and periodic nipple discharge. MRI scan of the head revealed a 1.6 cm pituitary macroadenoma which correlated with a markedly elevated prolactin level at 533.3. She was discharged with a prescription for Cabergoline 0.5 mg BID. In July 2022, the patient presented to the ED complaining of severe left breast pain with associated discharge for 4 days. She admitted to being non-adherent to Cabergoline treatment since April 2022 due to lack of endocrine follow-up. CT of the breast at that time showed a 3.8 cm subareolar abscess. Aspiration of the abscess revealed non-purulent fluid and cultures of the aspirate were negative. In February 2023, patient presented for right breast pain with a similar workup to previous hospitalization. MRI of the brain revealed a 1.6 cm sellar mass is unchanged since January 2022. Prolactin level was elevated at 652.4. Patient stated she has been off Cabergoline for the prior 5 months. She was subsequently seen for right and left mastitis 3 times over the next 12 months. Upon endocrine consultation, the patient was counseled on the importance of Cabergoline treatment in regression of future mastitis episodes, and the patient has subsequently not returned to our service. Conclusion: This case demonstrates the rare association between prolactin secreting pituitary adenomas and granulomatous mastitis that clinicians need to consider in order to avert delays in treatment and unnecessary hospitalizations. Specifically, when working up a patient with a history of IGM and prolactinemia, it is imperative to monitor prolactin levels periodically over an extended course of time with appropriate MRI imaging of the pituitary gland to assess for regression of prolactinoma and episodes of IGM. Presentation: 6/1/2024

7606 Partial Xp Duplication and Xq Deletion in a Patient with Premature Ovarian Failure: A Rare Case Report

Abstract Disclosure: A. Pataco: None. C.S. Moniz: None. C. Chaves: None. R. Medeiros: None. M. Ponte: None. B.D. Pereira: None. J. Anselmo: None. I. Sousa: None. Premature ovarian failure (POF) is a heterogeneous condition characterized by the cessation of ovarian function leading to amenorrhea before age 40. While the etiology of POF is diverse, the majority of cases are idiopathic, with a likely genetic basis. Xq abnormalities are commonly linked to POF, whereas Xp abnormalities are rare and infrequently reported.We describe a case of a 30-year-old woman with a personal history of depression, presenting to the Endocrinology department with an 8-month history of amenorrhea. Notably, her menstrual cycles had been irregular since menarche. Previously, a gynecological assessment led to the initiation of bromocriptine 5 mg/day for suspected microprolactinoma, indicated by symptoms of galactorrhea, elevated prolactin levels (112 ng/mL; Normal: 5.18-26.53), and a pituitary MRI showing a 3.5mm microadenoma. It is important to note her concurrent use of risperidone, sertraline, and lorazepam at that time.In the first evaluation at the Endocrinology department, the patient reported amenorrhea and denied galactorrhea. The physical examination was unremarkable with no evidence of hirsutism. The blood tests indicated hypergonadotropic hypogonadism, low levels of prolactin and Anti-Müllerian hormone: FSH 17 mIU/mL (Normal: 3.03-8.08), LH 8.30 mIU/mL (Normal: 1.80-11.78), 17-Beta Estradiol 11 pg/mL (Normal: 21-251), Total testosterone 20.1 ng/dL (Normal: 7.21-79.31), TSH 1.84 uIU/mL (Normal: 0.35-4.94), T4L 1.06 ng/dL (Normal: 0.70-1.48), PRL 1.8 ng/mL (Normal: 5.18-26.53), ACTH 21 pg/mL (Normal: 7.2-63.3), Cortisol 11.5 ug/dL (Normal: 3.7-19.4), IGF-1 130.2 ng/mL (Normal: 177-382), Anti-Müllerian hormone &amp;lt;0.1 ng/mL (Normal: 0.3-11.2).A diagnosis of premature ovarian failure was established. Bromocriptine was discontinued, and the hyperprolactinemia was attributed to the iatrogenic effects of her medications. A pelvic ultrasound showed no abnormalities. Cytogenetic analysis revealed an abnormal karyotype: 46 chromosomes with one X chromosome showing an anomalous configuration—partial deletion of the long arm and partial duplication of the short arm [duplication X(p22.33p11.23) with over 100 genes and deletion X(q24q28) including the FMR1 gene].The patient started hormone replacement therapy with estradiol valerate and medroxyprogesterone acetate, achieving regular menstruation thereafter. Literature review reveals that POF cases involving both partial Xp duplication and partial Xq deletion are exceedingly rare (only 6 reported cases). Genetic counseling is recommended for these patients, particularly for those considering parenthood. It is also advisable to assess the chromosomal alteration in parents to determine if the change is inherited and to evaluate the risk to other family members. Presentation: 6/2/2024

8412 Resolution of Central Hypothyroidism shortly after Transsphenoidal Surgery For Cushing’s Disease

Abstract Disclosure: L. Esper: None. A. Ibrahim: None. N. El Asmar: None. Background: Cushing's disease is a rare endocrine disorder characterized by excessive cortisol production, resulting in various metabolic disturbances. Hypercortisolism is known to cause central hypothyroidism. The mechanism is complex and involves hypercortisolism mediated decreased TRH and TSH secretion in addition to inhibition of peripheral deiodination. This case details the successful management and recovery of a patient with Cushing's disease and reversal of central hypothyroidism after pituitary surgery.Case:A 43-year-old man was evaluated for central hypogonadism, 20 pound weight gain with central weight distribution, and the development of purple abdominal striae for the past year. He had a normal thyroid exam and appeared euthyroid. He was alsodiagnosed with hypertension and prediabetes in the past yearrequiring medical therapy.A low dose dexamethasone suppression test (DST) resulted in AM cortisol of 12.9 mcg/dl. Two adequate 24hr Urinary cortisol measurements showed elevated cortisol excretion at 458 and 378mcg/24. Lab evaluation revealed elevated cortisol levels along with elevated adrenocorticotropic hormone (ACTH) levels(ACTH of 172 pg/ml with a cortisol level of 23.9 mcg/dl). A high dose DST demonstrated suppression of cortisol to 3.4 mcg/dl. MRI pituitary was performed which showed a clearright sided 7mm pituitary adenoma.Thyroid function tests performed were consistent with central hypothyroidism, with low levels of free thyroxine (FT4) at 0.67ng/dl along with an inappropriately low normal thyroidstimulating hormone (TSH) at 0.596 uIU/ml. Total T4 was low at 4 ug/dl in addition to a low total T3 of 66 ng/dl. Remaining labs revealed central hypogonadism along with slightly elevated prolactin of 16 ng/ml. He was not started on thyroid hormone.He then underwent transsphenoidal surgery for tumor removal. He developed post-operative adrenal insufficiency (cortisol 2.12 mcg/dl) 16 hours post-op after which he was started on hydrocortisone replacement, indicating remission. 12 hours post-op, his TSH was 0.656 uIU/ml with a free t4 of 0.79 ng/dl, both in the normal range. 36 hours post-op, TSH was 0.524 uIU/ml and free t4 was 1.15 ng/dl. Histopathological examination confirmed the diagnosis of an ACTH-secreting pituitary adenoma.At 4 weeks post-op, thyroid labs showed normal FT4 (1.07ng/dl) and TSH (2.06uIU/ml). Conclusion: Hypercortisolism causes a global inhibition of the thyroid axis, with decreased levels of TSH, T4, and T3 (1). Previous studies suggest the monitoring of thyroid function at 6 and 12 months after surgical cure of hypercortisolism. Our case suggests that the resolution of hypothyroidism occurs shortly after surgery for Cushing’s disease and the need for earlier monitoring. Presentation: 6/3/2024