Pituitary Corticotroph Adenomas Research Articles

TMET-04. METABOLOMICS ANALYSIS IN FUNCTIONING AND SILENT CORTICOTROPH ADENOMAS USING A TWO-DIMENSIONAL NANOMATERIAL HIGH-THROUGHPUT PLATFORM

Abstract Functioning pituitary corticotroph adenomas (CAs) originated from T-PIT lineage with an ACTH-positive staining cause Cushing’s Disease. However, silent CAs (SCAs) baring the same histological features present clinically non-functioning with more aggressive courses. Metabolites within the tumor microenvironment play critical roles in regulating tumor behaviors and responses to therapy. Understanding their distribution and concentration provides valuable insights for diagnosis and treatment. This study investigated metabolite patterns in functioning and silent CAs. We developed a novel two-dimensional nanomaterial platform for enhanced surface-assisted laser desorption/ionization mass spectrometry. Utilizing this platform, we analyzed the metabolomes of three functioning CAs and three SCAs. Our platform exhibited exceptional sensitivity and stability in detecting metabolite molecules. Analysis of the metabolomes revealed distinct spatial distributions and peak intensity of various metabolites, including carbohydrates, amino acids, organic acids, nucleotides, and their precursors. Notably, certain metabolites such as tryptophol, clopidogrel carboxylic acid, DG(20:4(8Z,11Z,14Z,17Z)-2OH(5S,6R)/0:0/i-16:0), S-(-)-ureidoglycolate, and PC(20:4(5Z,7E,11Z,14Z)-OH(9)/14:1(9Z)) were significantly enriched in functioning CAs compared to SCAs, while others, including Cer(d18:1/16:0), Dihydrocytochalasin B, and LysoPC(O-18:0/0:0), exhibited higher peak intensity in SCAs. Overall, our findings underscored the existence of unique metabolomic signatures distinguishing functioning CAs and SCAs. Heterogeneous metabolite distributions among functioning CAs and SCAs were revealed by our novel nanomaterial high-throughput platform, and unique metabolic signatures were identified. Metabolomics analysis holds promise for precise biomedical diagnostics and individualized therapeutic strategies in functioning and silent CAs.

6589 Antisense Oligonucleotides for Reducing ACTH Secretion in a Model of Cushing's Disease

Abstract Disclosure: M.S. Varughese: None. H. Eltumi: None. E.H. Kemp: None. J.D. Newell-Price: None. Antisense Oligonucleotides for Reducing ACTH Secretion in a Model of Cushing’s Disease Background: Cushing’s disease (CD) is a multi-system disorder with high morbidity and mortality characterised by pathologically raised serum cortisol due excess expression of proopiomelanocortin (Pomc) and overproduction of ACTH by a pituitary corticotroph adenoma. Trans-sphenoidal adenomectomy is the treatment of choice, but there is a 30% recurrence rate over time. Advances in medical therapy are needed. Antisense oligonucleotides (ASOs) can silence mRNA translation by specific base-pairing. Locked nucleic acid (LNA) and 2’-O-methyl (OMe) ribose terminals make ASOs more effective by improving affinity and resistance to nuclease degradation. Aims: To investigate the effectiveness of LNA- and OMe-modified anti-Pomc ASOs at reducing ACTH secretion from murine adrenotropic tumour (AtT20) cells. To analyse the nuclease resistance of Pomc ASOs and their ability to drive an immune response. Methods: Two ASOs (ASO2 and ASO3) were designed against Pomc with phosphorothioate backbones modified with either LNA or OMe ribose terminals. These were used in lipofectamine-mediated cell transfections of AtT20 cells and ACTH in the culture medium measured by immunoassay. ASO stability was assessed by nuclease degradation assays and immunogenicity by cytokine ELISAs. Results: When compared with untreated AtT20 cells, LNA- and OMe-modified Pomc ASOs at 1 nM significantly suppressed ACTH secretion for up to 120 h and 96 h, respectively (n = 4; Unpaired t tests, all P values < 0.05). In contrast, control treatments, including scrambled and mismatched ASOs, did not cause a significant reduction. For comparison, 1 nM of ASO2-OMe, ASO2-LNA, ASO3-OMe and ASO3-LNA lowered ACTH at 24 h by 62%, 71%, 63% and 79%, respectively. Modified Pomc ASOs showed 14-31% degradation over a 120-min incubation period with 3’- and 5’-exonucleases, whilst equivalent unmodified Pomc ASOs were completely degraded. No secretion of IFN-α, IFN-β, TNF-α, IL-6 or IL-1β was detected following transfection of AtT20 cells with Pomc ASOs. Conclusions:Pomc ASOs caused significant reduction of ACTH secretion from AtT-20 cells. LNA-modified Pomc ASOs were more effective than those with OMe modifications, with neither stimulating a detectable immune response. These ASOs hold promise as a systemic therapy for Cushing’s disease. Presentation: 6/3/2024

8133 Spatial Transcriptomic Profiling of Pituitary Corticotroph Carcinoma: Uncovering Architectural Complexity

Abstract Disclosure: D. Zhang: None. M. Bergsneider: None. M.B. Wang: None. W. Kim: None. H. Vinters: None. A.P. Heaney: None. Most pituitary corticotroph adenomas are benign but ∼15% are refractory to conventional surgical, medical and even radiotherapeutic management. This tumor subset invade sellar adjacent structures, and in rare cases metastasize locally within the central nervous system or to neck lymph nodes (LN) or more distant organs such as the liver. To better understand the potential interactions between tumor cells and neighboring tissues during these progressive stages, we used spatial transcriptomics (ST, Visium, 10x Genomics) to profile the genetic composition and native architecture of 4 surgically resected corticotroph tumor paraffin-embedded samples collected from the same patient over several years. Samples 1& 2 invaded the sino-nasal mucosa, sample 3 the parietal dura, sample 4 the clival bone, and sample 5 had metastasized locally to a neck LN. Quality of the 4 samples was confirmed by DV200 score (51 ± 7%). An average of 2,473 tissue spots per tissue sample were obtained after sequencing with a median of 4,893 genes detected per spot. We then used the Seurat analytic pipeline to reconstitute spatial transcriptional distribution that authentically mirrored histologically verifiable structures. These included the main tumor area itself, it’s invading tumor edge, adjacent normal epithelium, dura, and LN tissue. Further deconvolution analysis revealed a distinct cellular composition at the invading tumor edge which was tissue context specific. For instance, a proliferative cell population was noted between the central tumor area and it’s invasive margin, B cell and fibroblast cell enrichment was prominent at sino-nasal mucosal invasive margins, whereas endothelial and pericyte cells were prominent along the tumor/ normal pituitary border. . As expected, the central tumor area expressed genes associated with corticotroph hormone production including POMC, NNAT, GAL and GNAS, genes associated with mitochondrial energy metabolism such as ATP5F1E, NDUFA8 and COX7B as well as transcripts related to lipid kinase activity (GKG, CERKL, PIK3C2G, DGKK). Most intriguingly, tumor cells at the fore-front of the invading edge expressed high level of cyclin-dependent kinases, potentially reflecting higher proliferative rates of these invasive margin cells. Additional studies to validate and define the role of theses invasive margin transcripts are now warranted to translate our profiling findings into potential drug targets. In summary, this is the first use of spatial transcriptomics to delineate the evolving transcriptomic features in a series of surgically resected pituitary corticotroph tumors from the same patient that progressed over time to a locally metastatic corticotroph carcinoma. It provides unparalleled insights into the differential transcriptional topography of corticotroph tumor tissue and most importantly, its invading edge and may identify novel therapeutic targets. Presentation: 6/3/2024

8319 Pituitary Apoplexy Leads to the Spontaneous Resolution of Hypercortisolism Secondary to Cushing Disease: A Clinical Case

Abstract Disclosure: N. Sweis: None. J. Sanchez Perez: None. M. Fariduddin: None. R.M. Sargis: None. D.J. Toft: None. S. Reutrakul: None. Background: Pituitary apoplexy is a potentially fatal condition involving the infarction or hemorrhage of the pituitary gland. Rarely, it can occur in the setting of an ACTH-secreting pituitary adenoma. Clinical Case: A 27-year-old female with a past medical history of obesity, spontaneous miscarriages, and amenorrhea presented to the ER with an acute onset frontal headache of throbbing quality, associated with nausea and vomiting. The headache began two days prior, rapidly intensified, and did not improve with oral acetaminophen. CT of the head revealed an enlarged pituitary gland, while neurovascular imaging showed no abnormalities. Her neurologic examination was normal. She denied visual changes, photophobia, neck rigidity, fevers, chills, or recent infections. Furthermore, she endorsed a weight gain of about 40 pounds over the past year despite no change in dietary habits. This was accompanied by amenorrhea, hair thinning, itchy comedonal acne, hirsutism, and a loss of libido. Her physical examination was remarkable for the presence of cushingoid features including violaceous abdominal striae, facial acne, moon facies, a dorsal fat pad, and acanthosis nigricans around the neck and axillae. Pituitary MRI with and without contrast showed an enlarged sellar and suprasellar macroadenoma measuring approximately 2.1x1.4x1.2 cm abutting the optic chiasm. The visualized lesion contained hemorrhagic products, suggesting pituitary apoplexy. Biochemical testing on admission included a low morning plasma cortisol of 6.5 ug/dL (ref. range: 6.7-22.6 ug/dL), a 24-hour urine free cortisol of 12.0 (<=45.0 ug/24 hour), and an elevated ACTH of 145.0 pg/mL (7.2 - 63.3 pg/mL). A1c was 5.8% (<5.7%). Serum levels of prolactin, IGF1, GH, LH, FSH, TSH, Free T4, estradiol, total and bioavailable testosterone were within normal limits. She was evaluated with an ACTH stimulation test, which showed a morning cortisol level of 1.2 ug/dL at baseline, lower from prior. Cortisol levels were adequately increased at 19.6 ug/dL and 22.6 ug/dL, 30 and 60 minutes after the administration of Cosyntropin 250 mcg, respectively (>=18 ug/dL after 30-60 mins). The level of ACTH at the time was also decreased to 76.6 pg/mL. The patient was therefore started on steroid replacement therapy with hydrocortisone and later underwent transsphenoidal resection of the pituitary mass without complications. Histopathological examination of the resected mass showed pituitary adenoma cells with diffuse weak to moderate ACTH staining, most consistent with a sparsely granulated corticotroph pituitary adenoma. Conclusion: We report an interesting case of Cushing disease that spontaneously resolved after pituitary apoplexy. Our case underlines the importance of close monitoring of such patients who may rapidly undergo a period of adrenal insufficiency after hypercortisolism. Presentation: 6/3/2024

6400 An Unusual Presentation of Silent Corticotroph Pituitary Macroadenoma

Abstract Disclosure: N. Mon: None. V. Lohano: None. B. Williams: None. N. Lehman: None. R. Kulkarni: None. S.L. Mokshagundam: None. Silent Corticotroph Pituitary Adenomas (SCA) are a rare group of nonfunctioning pituitary adenomas (NFA) comprising 3-6% of all pituitary adenomas and up to 20% of corticotroph adenomas. SCA are biologically and clinically distinct from Cushing disease and NFA. SCA present with headache, visual field impairment, hypopituitarism, and pituitary apoplexy. We present a case of SCA with the initial presentation of syncope with undetectable ACTH and very low AM cortisol level.A 67 year-old-female was incidentally found to have a pituitary macroadenoma in MRI brain for syncope work up in 2017. MRI reported 1.4 x 1.2 x 1.3 cm sellar mass with suprasellar extension, minimal mass effect on the optic chiasm and no cavernous sinus invasion. Initial labs showed ACTH <5 (7.2-63.3 pg/mL), AM cortisol 0.8 (6-28ug/dl), Prolactin 101.1 (3.3-27 ng/mL), TSH 0.08 (0.34-5.60 uIU/mL), Free T4 0.6 (0.58-1.64 ng/dL), FSH 1.7 (2-5 mIU/mL), LH <0.2 (1-13 mIU/mL), IGF-1 33 ( 41-279 ng/mL). ACTH stimulation test: cortisol 0.5 ug/dl at baseline, 5.8 ug/dl at 60min. She was diagnosed with panhypopituitarism and hyperprolactinemia due to stalk effect. Hydrocortisone and Levothyroxine (LT4) were started. She underwent pituitary macroadenoma resection for optic chiasm decompression in 2017. Pathology reported pituitary neuroendocrine tumor (pitNET), but no immunostaining was done at that time. Follow up MRI in 2019 showed residual pituitary tumor. In 2023, she endorsed headaches, mood changes, fatigue and weight gain. Physical exam was unremarkable except BMI 34.75. Prolactin, Free T4, IGF-1 were normal. MRI in 2023 revealed recurrent and enlarging pituitary adenoma (1.9 x 1.4 x 1.6 cm) with suprasellar extension, abutting the optic chiasm, and left cavernous sinus invasion with internal carotid artery encasement. She underwent revision transsphenoidal resection of pituitary tumor to decompress the optic chiasm with plan for subsequent focused radiation to the cavernous sinus portion. Postoperative period was uneventful and hydrocortisone and LT4 were continued on discharge. Final pathology reported silent corticotroph lineage pitNET with low Ki67, immunostaining positive for TPIT, CAM5.2, and negative for ACTH. ACTH-negative SCA are a rare subtype and more likely to have lower ACTH levels, and multiple microcysts on MRI than ACTH-positive SCA. New WHO classification of pitNET highlights the histological typing and subtyping based on immunostaining of pituitary lineage transcription factors as the cornerstone for accurate classification. SCA are more biologically aggressive tumors with a high propensity of recurrence and resistance to conventional treatment. TPIT and ACTH immunostaining significantly improved the diagnosis of SCA and thereby close clinical follow up for early recognition and management of SCA recurrence. Absence of serum markers of recurrence makes this challenging. Presentation: 6/1/2024

6630 Crooke Cell Pituitary Adenoma Without a Cushingoid Appearance

Abstract Disclosure: J. Hodge: None. S. Idriss: None. I. Jamal: None. R. Panta: None. Background: Crooke cell pituitary adenomas are corticotroph adenomas with Crooke’s cell changes, which are cytoplasmic accumulation of cytokeratin filaments in response to glucocorticoid excess. They are aggressive, invasive tumors, typically macroadenomas, with a high rate of Cushing’s disease and post -treatment (surgery and/or radiotherapy) recurrence. We present a case of Crooke cell pituitary adenoma without a Cushingoid appearance. Clinical Case: A 66-year-old Hispanic male with a 16-year history type II diabetes mellitus with retinopathy, presented with a pituitary macroadenoma at age 60. This was found incidentally when he had a brain CT for evaluation of vertigo. Subsequent brain MRI demonstrated a large 2.4 x 2.0 x 1.7 cm pituitary macroadenoma with extension into the suprasellar cistern and the left cavernous sinus. He was asymptomatic, without Cushingoid features. Hormonal evaluation revealed central hypogonadism and hypothyroidism, mildly elevated prolactin of 39.3 (4-15.2 ng/mL) and morning cortisol level of 12.7 (6-18.4 ug/dL). A 24-hour urine cortisol was normal. He was started on testosterone and thyroid hormone replacement therapy. His diabetes mellitus became progressively difficult to control with a peak HbA1C of 10.1%, about 7 years prior the macroadenoma finding. His HbA1C remained persistently elevated in the 8.1-9.5% range despite being on 6 anti-hyperglycemic agents, including basal insulin. A morning ACTH level 4 years after the initial visit, was 115 (6-50 pg/mL) with a cortisol level of 13.7 (6-18.4 ug/dL). Repeat morning ACTH and cortisol levels 7 months later were very similar. 5 years after the macroadenoma finding, he was noted to have worsening glaucoma, which was believed to be due to optic nerve compression. Therefore, he underwent endoscopic transphenoidal resection for tumor debulking. Pathology supported the diagnosis of Crooke cell corticotroph pituitary adenoma. Repeat brain MRI 3-months post-surgery demonstrated residual tumor, but normal optic chiasm and optic tracts. He had an abnormal dexamethasone suppression test prior to surgery (cortisol 6.4 ug/dL) and continued to do so post-operatively (cortisol 3.7 ug/dL with persistently elevated ACTH). Just prior to his surgery, testosterone replacement therapy was held. Total testosterone level after surgery was normal 309.6 (280-800 ng/dL) and free testosterone 7 (5-21 ng/dL); he remained off replacement therapy. Conclusion: Crooke cell pituitary adenomas are rare with limited data on prognosis and guidance for clinical management. Some patients may have subtle features of hypercortisolism, such as difficult to control diabetes mellitus, without an overt Cushingoid appearance. Presentation: 6/1/2024

PCSK1N as a tumor size marker and an ER stress response protein in corticotroph pituitary adenomas.

Silent corticotroph adenoma (SCA) exhibits more tumor aggressiveness features than functioning adenomas (FCA). We aimed to investigate PCSK1N expression in CA and examine if ER stress-induced responses affect cell survival in a corticotroph tumor cell model. Clinical and imaging characteristics were recorded in 33 patients with FCA (20 women, 11 macroadenomas) and 18 SCA (8 women, all macroadenomas). Gene expression of proopiomelanocortin (POMC), T-box transcription factor 19(TBX19)/TPIT, proprotein convertase subtilisin/kexin type 1(PCSK1)/PC1/3, and its inhibitor PCSK1N, was measured by RT-qPCR in adenoma tissue.Mouse pituitary corticotroph tumor (AtT-20) cells were treated with tanespimycin (17-AAG), a HSP90 chaperone inhibitor, to induce ER stress, followed by gene and protein analyses. POMC, TPIT, and PCSK1 expression were higher, whereas PCSK1N was lower in FCA compared to SCA. PCSK1N correlated with POMC (rs= -0.514, p <0.001), TPIT (rs= -0.386, p = 0.005), PCSK1 (rs= -0.3691, p = 0.008), and tumor largest diameter (rs= 0.645, p <0.001), in all CA. Induction of ER stress by 17-AAG in AtT-20 cells led to a decrease of POMC and an increase of PCSK1N gene expression at 24h. Moreover, a downregulation of cell cycle, apoptosis, and senescence pathways, and alterations in cell adhesion and cytoskeleton were observed at the protein level. PCSK1N is higher in SCA compared with FCA, and associated with corticotroph cell markers and tumor size. PCSK1N is likely to be part of the adaptive response to ER stress, potentially conferring a survival advantage to the corticotroph tumor cell in conjunction with other proteins.

Somatic USP8 alteration affects the immune landscape of corticotroph pituitary adenomas- a pilot study.

Somatic mutations in ubiquitin-specific protease-8 (USP8), encoding a deubiquinating protein, are found in approximately 30% of corticotroph-derived pituitary adenomas (CPAs). Stratifin, a protein encoded by SFN, inhibits USP8 catalytic activity. USP8 has immunomodulating properties that have been demonstrated in non-tumoral diseases. We assessed the influence of USP8 on the immune landscape of CPA and validated this effect and its dependency on stratifin in large cohorts of non-pituitary tumors. We analyzed data of CPA samples (n = 20) and additional non-pituitary tumors from the TCGA database, using transcriptome signature-recognition algorithms. Immune tumor microenvironment (iTME) was compared both by USP8 and SFN expression levels (n = 843) and by USP8 mutation status and SFN expression (n = 12,389). CPA with activating USP8 mutations was associated with "cold" iTME compared with wild-type USP8 CPA, as reflected by lower fractions of immune cells, including B cells, CD4, regulatory and gamma/delta T cells, natural killer cells, M0 and M1 macrophages, dendritic cells, and eosinophils (p < 0.05 for all comparisons). Pathways altered by the presence of USP8 mutation, based on the most differentially expressed genes (3061 genes), included microglia pathogen phagocytosis and multiple toll-like receptor signaling pathways (p < 0.0001). In a validation analysis based on large cohorts of non-pituitary tumors, high expression of USP8 was associated with a suppressed iTME effect that was augmented by a low SFN expression. Our data demonstrate for the first time, to our knowledge, a distinct immune landscape of tumors based on USP8 status and expression and the dependency of this immunological effect on SFN expression.

Clinicoradiological Parameters and Biochemical and Molecular Alterations Predicting Remission and Recurrence After Surgical Treatment of Corticotroph Adenomas—Cushing Disease

ObjectivesEndonasal endoscopic transsphenoidal surgery (TSS) and resection of pituitary adenomas is considered to be the gold standard treatment for Cushing’s Disease (CD). Even with various recent advances in management, disease persistence and recurrences are common in these patients. The remission rate in the global population after surgery has been reported to vary widely from 64 to 93%. This study aims to determine various clinical, biochemical, radiological and histological factors that correlate with persistence and recurrence in patients with CD. This study also aims to understand the clinicopathological significance of EGFR-MAPK, NF-kB and SHH pathway activation and to study the protein expression levels of activation markers of these pathways viz. c-Fos , c-Jun, GLI-1 , pMEK, NR4A1 and p44 in functioning corticotroph pituitary adenomas. MethodsFrom January 2009 to September 2022, the clinical data of 167 patients who underwent surgical treatment (n=174 surgeries) for Cushing’s disease was ambispectively analysed with a median follow up of 8.1 years (1-13.29 years). The preoperative clinical, biochemical, radiological features, operative findings, postoperative clinical and biochemical data, histopathological and molecular profile, were retrieved from electronic records. The patients were followed up to assess the remission status. ResultsAmong the 174 surgeries performed, 140 were primary surgeries, 22 were revision surgeries, 24 surgeries were for paediatric patients and 12 surgeries were performed in patients with Nelson syndrome. In the primary surgery cohort, 74.3% were females and the average age was 28.73 years (SD 10.15). 75% of the patients experienced remission after primary surgery compared to 47.4% in revision surgery. The remission rate in paediatric patients was 55.5%. Post-operative day 1 plasma cortisol (p<0.001; AUC 0.8894 [0.8087-0.9701]) and ACTH (p<0.001; AUC 0.9 [0.7386-1]) levels were seen to be strong independent predictors of remission in the primary surgery cohort. Remission rates after Endoscopic TSS were more than that after microscopic TSS, in patients undergoing primary surgery (81.08% vs 57.14%; p=0.008). Presence of adenoma on histopathological examination (HPE) was also a strong predictor of disease remission (p=0.020). On categorising based on surgical approach and HPE, microscopically operated patients without histopathological evidence of adenoma had significantly higher odds of non-remission (OR 38.1 95% CI 4.2-348.3) compared to endoscopically operated patients with adenoma on HPE. Lower immune reactivity score (IRS) of NR4A1 was found to correlate with higher remission rates (p=0.074). However, none of the molecular markers studied viz. c-Fos , c-Jun, GLI-1, pMEK and p44 showed a significant correlation with the preoperative cortisol values. ConclusionRemission rate after primary surgery is higher as compared to that after revision surgery, and that in paediatric patients is lower as compared to adults. Post-operative day 1 plasma cortisol and ACTH levels are strong independent predictors of remission in the primary surgery cohort. Endoscopic approach with histopathological evidence of adenoma is associated with a higher remission rate and thus endoscopy should be the approach of choice in these patients with the goal of identification of an adenoma on histopathological analysis.

Cytologic features of canine melanotroph and corticotroph pituitary adenomas.

The introduction of intraoperative cytology revolutionized neurosurgical procedures in human medicine, providing real-time diagnostic guidance to surgeons and contributing to improved patient outcomes. In the realm of veterinary medicine, the understanding of pituitary tumors in dogs and cats remains limited due to challenges in obtaining antemortem samples of central nervous system lesions. The aim of this study was to describe the cytologic features of pituitary adenomas in 12 dogs that underwent hypophysectomy. The series included nine melanotroph adenomas and three corticotroph adenomas. Definitive diagnosis was based on histopathology and immunohistochemistry. Cytologically, the adenomas had high numbers of bare nuclei and intact cells that were round to polygonal and situated individually or in small clusters. The intact cells had round to oval, eccentric nuclei with finely stippled chromatin and one to three prominent nucleoli and ample to abundant lightly basophilic to amphophilic, grainy cytoplasm with distinct borders, and variable numbers of discrete vacuoles. Mild-to-moderate anisocytosis and anisokaryosis, occasional binucleation, rare and atypical mitotic figures, and nuclear molding were also observed. The results suggest that intraoperative cytology of canine pituitary adenomas holds promise as a valuable diagnostic tool, aiding swift differentiation from other sellar masses before histologic confirmation. Cytologic characterization of pituitary adenomas in dogs is exceptionally rare in the scientific literature, making this study one of the first to offer a comprehensive description of these cytologic features.

SAT618 Uncovering The Role Of O-glcnacylation In Pituitary Adenoma Pathogenesis: Insights From Corticotroph Tumors

Abstract Disclosure: L.J. Massman: None. R. Gonzalez: None. B. Laing: None. D. Coss: None. A.G. Ioachimescu: None. N. Zwagerman: None. S. Olivier-Van Stichelen: None. Functioning corticotroph pituitary adenomas are associated with high mortality, morbidity, and a high propensity of biochemical recurrence postoperatively. Silent corticotroph adenomas cause mass-effect manifestations and have an increased risk for tumor regrowth. The pathogenetic mechanisms responsible for the clinical course of corticotroph PA are poorly understood. In this study, we investigated the role of the O-GlcNAc posttranslational modification in their pathophysiology. O-GlcNAcylation is involved in protein signaling pathways and deregulated in cancers and diabetes. First, we performed RNA-sequencing in functioning and silent corticotroph and gonadotroph adenomas (n=25). We discovered that O-GlcNAc enzymes were upregulated in ACTH-secreting corticotroph tumors and correlated with larger, more invasive tumors. Also, an in vitro mechanistic analysis of corticotroph tumor cells (ATt-20) demonstrated that O-GlcNAcylation was essential for their proliferation and secretory ability. Specifically, O-GlcNAcylation affected Proopiomelanocortin mRNA splicing and stability, suggesting a new mechanism of fast hormonal response in corticotropes. Overall, our study indicates a key role for O-GlcNAcylation in corticotroph adenomas’ cellular proliferation and hypersecretion. Presentation: Saturday, June 17, 2023

THU010 A Case Of Cushing's Disease Due To T-pit Positive, ACTH Negative Aggressive Corticotroph Pituitary Adenoma

Abstract Disclosure: C. Gopinath: None. P. Pagadala: None. C. Choudhary: None. D.R. Tilden: None. Introduction: The 2017 WHO classification of Pituitary Adenomas utilizes pituitary transcription factors for its classification system. It can be helpful in identifying cell lineages in adenomas without expression of pituitary hormones. We describe a case of recurrent Cushing’s disease due to an ACTH negative, elevated Ki-67, TPIT positive aggressive corticotroph adenoma. Case report: A 54-year-old male presented with c/o diplopia, fatigue, decreased sexual drive. MRI brain showed a 2.4 x 1.4 x 1.6 cm sellar mass with suprasellar extension, displacement of the optic chiasm, extension into the left cavernous sinus. Hormonal work up showed evidence of central hypothyroidism (free T4- 04 ng/dl(0.6-1.6 NG/dl), TSH- 0.08 MCU/ml(0.35-5.00 MCU/ML) low testosterone (76 ng/dL(270-1070 NG/DL)),random cortisol of 20.1mcg/dL( 5.0-20.0 MCG/DL), ACTH- 136 pg/ml(7-63 pg/ml). Patient underwent transsphenoidal surgery (TSS). Pathology showed a pituitary adenoma of 1.5 cm with conspicuous mitoses and elevated Ki67 proliferation index (range- 15-35%). Immunohistochemistry was positive for prolactin; synaptophysin and negative for ACTH, GH, FSH, LH, TSH. Transcription factors for T-pit, Pit-1 and SF-1 were not assessed. Diagnosis of non-functioning adenoma was made. Repeat MRI showed residual tumor and due to elevated Ki-67, radiation therapy was recommended which was received at an outside hospital. 2.5 years later he was readmitted with profound hypokalemia, metabolic alkalosis and altered mental status. He appeared Cushingoid with facial plethora, moon facies, dorsocervical fat pad and violaceous striae on the abdomen. Dexamethasone suppression testing revealed elevated cortisol of 26.7 mcg/dl, AM cortisol -44.7mcg/dl (6.7-22.6mcg/dl),ACTH-280 pg/mL(7-63 pg/mL),24 hour urine free cortisol was elevated 2065 mcg/24 hour(3.5-45 mcg/24 hr). Given initial negative ACTH staining on the macroadenoma, there was concern for ectopic ACTH given acute presentation and absence of growth on the MRI compared to post radiation scans. IPSS was pursued which showed central ACTH source. Given stable size of residual tissue post radiation and location on MRI neurosurgery recommended against repeat surgery at this time. Patient was started on medical treatment for hypercortisolism with ketoconazole but had elevated liver enzymes limiting dose increase. Clinically patient continued to decline. Given significantly elevated cortisol with high risk of infectious and thrombotic events, poor short term outcomes decision was made for b/l adrenalectomy which he underwent successfully. Immunostains were ordered on the original adenoma resected and showed strong positivity for TPIT. Conclusion: Immunohistochemistry is an important step to aid classification of pituitary adenoma. Management of aggressive corticotroph adenoma with high ki-67 index can be a therapeutic challenge. Presentation: Thursday, June 15, 2023

Crooke Cell Adenoma Confers Poorer Endocrinological Outcomes Compared with Corticotroph Adenoma: Results of a Multicenter, International Analysis

Crooke cell adenomas (CCAs) are a rare, aggressive subset of secretory pituitary corticotroph adenomas (sCTAs) found in 5%-10% of patients with Cushing disease. Multiple studies support worse outcomes in CCAs but are limited by small sample size and single-institution databases. We compared outcomes in CCA and sCTA using a multicenter, international retrospective database of high-volume skull base centers. Patients surgically treated for pituitary adenoma from January 2017 through December 2020 were included. Among 2826 patients from 12 international centers, 20 patients with CCA and 480 patients with sCTA were identified. No difference in baseline demographics, tumor characteristics, or postoperative complications was seen. Microsurgical approaches (60% CCA vs. 62.3% sCTA) were most common. Gross total resection was higher in CCA patients (100% vs. 83%, P= 0.05). Among patients with gross total resection according to intraoperative findings, fewer CCA patients had postoperative hormone normalization of pituitary function (50% vs. 77.8%, P < 0.01) and remission of hypersecretion by 3-6 months (75% vs. 84.3%, P < 0.01). This was the case despite CCA having better local control rates (100% vs. 96%, P < 0.01) and fewer patients with remnant on magnetic resonance imaging (0% vs. 7.2%, P < 0.01). A systematic literature review of 35 studies reporting on various treatment strategies reiterated the high rate of residual tumor, persistent hypercortisolism, and tumor-related mortality in CCA patients. This modern, multicenter series of patients with CCA reflects their poor prognosis and reduced postsurgical hormonal normalization. Further work is necessary to better understand the pathophysiology of CCA to devise more targeted treatment approaches.

An individualized approach to the management of Cushing disease.

Cushing disease caused by an adrenocorticotropic hormone (ACTH)-secreting pituitary corticotroph adenoma leads to hypercortisolaemia with high mortality due to metabolic, cardiovascular, immunological, neurocognitive, haematological and infectious conditions. The disorder is challenging to diagnose because of its common and heterogenous presenting features and the biochemical pitfalls of testing levels of hormones in the hypothalamic-pituitary-adrenal axis. Several late-night salivary cortisol and 24-h urinary free cortisol tests are usually required as well as serum levels of cortisol after a dexamethasone suppression test. MRI might only identify an adenoma in 60-75% of patients and many adenomas are small. Therefore, inferior petrosal sinus sampling remains the gold standard for confirmation of ACTH secretion from a pituitary source. Initial treatment is usually transsphenoidal adenoma resection, but preoperative medical therapy is increasingly being used in some countries and regions. Other management approaches are required if Cushing disease persists or recurs following surgery, including medications to modulate ACTH orblock cortisol secretion or actions, pituitary radiation, and/or bilateral adrenalectomy. All patients require lifelong surveillance for persistent comorbidities, clinical and biochemical recurrence, and treatment-related adverse effects (including development of treatment-associated hypopituitarism). In this Review, we discuss challenges in the management of Cushing disease in adults and provide information to guide clinicians when planning an integrated and individualized approach for each patient.

Differentiation of silent corticotroph pituitary neuroendocrine tumors (PitNETs) from non-functioning PitNETs using kinetic analysis of dynamic MRI

PurposeSilent corticotroph pituitary adenomas (SCAs)/pituitary neuroendocrine tumors (PitNETs) are common non-functioning pituitary adenomas (NFAs)/PitNETs with a clinically aggressive course. This study aimed to investigate the ability of time-intensity analysis of dynamic magnetic resonance imaging (MRI) for distinguishing adrenocorticotropic hormone (ACTH)-positive SCAs and ACTH-negative SCAs from other NFAs.Materials and methodsWe retrospectively evaluated the dynamic MRI findings of patients with NFAs. The initial slope of the kinetic curve (slopeini) obtained by dynamic MRI for each tumor was analyzed using a modified empirical mathematical model. The maximum slope of the kinetic curve (slopemax) was obtained by geometric calculation.ResultsA total of 106 patients with NFAs (11 ACTH-positive SCAs, 5 ACTH-negative SCAs, and 90 other NFAs) were evaluated. The kinetic curves of ACTH-positive SCAs had significantly lesser slopeini and slopemax compared with ACTH-negative SCAs (P = 0.040 and P = 0.001, respectively) and other NFAs (P = 0.018 and P = 0.035, respectively). Conversely, the slopeini and slopemax were significantly greater in ACTH-negative SCAs than in NFAs other than ACTH-negative SCAs (P = 0.033 and P = 0.044, respectively). In receiver operating characteristic analysis of ACTH-positive SCAs and other NFAs, the area under the curve (AUC) values for slopeini and slopemax were 0.762 and 0748, respectively. In predicting ACTH-negative SCAs, the AUC values for slopeini and slopemax were 0.784 and 0.846, respectively.ConclusionsDynamic MRI can distinguish ACTH-positive SCAs and ACTH-negative SCAs from other NFAs.

Comparison of the preoperative diagnostic accuracy of BIPSS versus MRI for Cushing disease: a single-centre experience

BackgroundCushing disease (CD) arises due to a pituitary corticotroph adenoma, which is the most common cause of Cushing syndrome (CS). Bilateral inferior petrosal sinus sampling (BIPSS) is a safe method for differentiating CD from ectopic adrenocorticotropic hormone (ACTH)-dependent CS. Enhanced high-resolution magnetic resonance imaging (MRI) can localize tiny pituitary lesions. The aim of this study was to compare the preoperative diagnostic accuracy of BIPSS versus MRI for CD in CS patients. We performed a retrospective study of patients who underwent BIPSS and MRI between 2017 and 2021. Low- and high-dose dexamethasone suppression tests were performed. Blood samples were collected simultaneously from the right and left catheter and femoral vein before and after desmopressin stimulation. MRI images were obtained, and endoscopic endonasal transsphenoidal surgery (EETS) was performed in confirmed CD patients. Dominant sides of ACTH secretion during BIPSS and MRI were compared with surgical findings.ResultsTwenty-nine patients underwent BIPSS and MRI. CD was diagnosed in 28 patients, 27 of whom received EETS. Localizations of microadenomas by MRI and BIPSS agreed with the EETS findings in 96% and 93% of the cases, respectively. BIPSS and EETS were successfully performed on all patients.ConclusionBIPSS was the most accurate method (gold standard) for establishing a preoperative diagnosis of pituitary-dependent CD and was more sensitive than MRI in diagnosing microadenoma. High-resolution MRI with enhancement had an advantage over BIPSS in microadenoma lateralization diagnostics. The combined use of MRI and BIPSS could improve the preoperative diagnosis accuracy in ACTH-dependent CS patients.

PMON157 Evidence For Locally Produced Cortisol in Pituitary Tissue

Abstract Double or multiple pituitary adenomas are rare and account for only 1.6-3.3% of all corticotroph tumors. We describe 2 distinct pituitary corticotroph adenomas in a 43-year-old female presenting with ACTH-dependent Cushing disease (CD). Although pre-operative pituitary MRI noted a single 8×6mm left sided pituitary microadenoma, which was confirmed at trans-nasal trans-sphenoidal surgery, she was found to an additional 7mm right sided microadenoma. Histopathology confirmed 2 separate corticotroph adenomas and she exhibited immediate remission of her CD with nadir cortisol of 1mcg/dL. Whole exome sequencing demonstrated a somatic mutation in the 21-alpha-hydroxylase (CYP21A2) gene in both tumors. CYP21A2 transcript and protein expression were absent in the index case but both CYP21A2 transcript and protein were demonstrated in a series of 9 other pituitary corticotroph adenomas and 12 normal pituitary tissues. This unusual case which prompted us to examine CYP21A2 expression in the pituitary allows us to describe for the first time evidence of locally generated pituitary-derived cortisol and indicate this could play a paracrine role on the corticotroph and may contribute to growth of ACTH pituitary adenomas in some instances. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

RF01 | PMON168 Hedgehog-Induced Somatostatin Receptor Expression is Inhibited by the Activation of the Glucocorticoid Receptor Signaling Pathway in Human Pituitary Adenoma Organoids

Abstract Background Cushing's disease (CD) is an endocrine disorder caused by an ACTH-secreting pituitary adenoma that is associated with increased morbidity and mortality. Because somatostatin inhibits pituitary ACTH secretion, the somatostatin receptor subtypes (SSTR) 2 and 5 have been targets of medical therapies for CD. The SSTR5 is most consistently and strongly expressed in corticotroph pituitary tumors but the SSTR dynamics in CD during treatment and responses to cortisol level changes are far from being understood. Studies in adult stomach demonstrated that the Hedgehog (Hh) signaling pathway is critical for the regulation of somatostatin and SSTR signaling. While Hh signaling is known to be essential during the embryonic development of the pituitary and in the adult gland, the mechanism by which Hh signaling regulates SSTR expression in CD is unknown. Hypothesis Activation of glucocorticoid receptor (NR3C1, GR) results in the inhibition of Hh transcription factor GLI1 leading to reduced SSTR expression. Methods We developed a human pituitary adenoma organoid model (hPITOiPSC) from induced pluripotent stem cells treated with the glucocorticoid receptor (GR) antagonist mifepristone, and co-treated them with or without SSTR agonists pasireotide or octreotide. In a separate series of experiments, the role of Hh transcription factor GLI1 was identified using hPITOiPSC treated with mifepristone with or without GANT61 (GLI inhibitor) or ketoconazole (Smoothened, SMO inhibitor). CRISPR-Cas9 gene editing of hPITOiPSC pituitary organoids were used to model the development of pituitary corticotroph adenomas in the presence of BRAF, USP48 and USP8 mutations. Human pituitary adenoma tissue harvested fresh during pituitary surgery was used to generate pituitary corticotroph subtype adenoma organoids (hPITOs). Dose responses using standard of care drugs were performed using the hPITOs. Results 1) At baseline SSTR2 was abundantly expressed within hPITOiPSC. Mifepristone induced significant increases in ACTH secretion and POMC expression that correlated with induced SSTR2 and 5. Mifepristone-induced SSTR2 and 5 expression was significantly inhibited in the presence of GANT61, whereas SMO inhibitor ketoconazole had a minimal effect on mifepristone-induced SSTR2/5, POMC expression and ACTH secretion. Dexamethasone alone significantly inhibited both GLI1 and SSTR2 and 5. 2) While pituitary organoids that were differentiated from control iPSCs (iPSCCtrl) expressed all major hormone-producing cell lineages, there was a significant increase in ACTH expression with loss of PIT1, GH, FSH, LH and PRL in iPCSs expressing mutated BRAF, USP48 and USP8. Organoids expressing a mutation in BRAF had significantly higher SSTR2 expression levels compared to controls. 3) HPITOs generated from pituitary adenomas of CD patients showed differential organoid responses to pasireotide, mifepristone, and ketoconazole. Conclusion Within pituitary adenomas, the SSTR is a transcriptional target of Gli1, and this response is blocked by the activation of the GR. These data form the basis of combination therapy for CD with mifepristone and pasireotide. Presentation: Saturday, June 11, 2022 1:37 p.m. - 1:42 p.m., Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

ODP304 Cyclic Cushing Disease: A Diagnostic Challenge

Abstract Background Cyclic Cushing syndrome is a clinical challenging diagnosis due to an unpredictable duration of periodic hypercortisolemia shifting with normocortisolemia periods. Only small proportion of such cases are due to a corticotroph pituitary adenoma with cyclic activity. Clinical case: 27-year-old after she stopped nursing her baby, she had no resumption of menses. She then developed mild headache and weight gain of 20kg throughout 3 months. She also developed facial hair, acne, easy bruising and striae. She was evaluated by a local physician where Cushing syndrome (CS) was suspected. Local testing showed the following results: UFC: 1117 and 1572 mcg/24h (&amp;lt;403mcg/24h), low dose DST of 595.8 nmol/l (&amp;lt;50nmol/l) and ACTH 60 pg/mL (10-100pg/mL). An MRI identified a 6 mm pituitary adenoma. The patient was sent to our pituitary clinic under the diagnosis of Cushing disease (CD). Upon examination at our institution, the patient reported asthenia, mood changes, depression and hirsutism. The physical examination revealed classical signs of CS. No other comorbidities were detected. A seven-hour 7mg dex infusion testwas performed (1), with basal cortisol of 187.5 nmol/l, early suppression of 12.6 nmol/l and late suppression of 27.5 nmol/l which is negative for hypercortisolism. As the high suspicion of CS, the patient was followed monthly with UFC and serum cortisol. During this normocortisolemia period the patient lost 10kg of weight, recovered its menses and coloration changes of striae. Laboratory follow up UFC of 67, 71 mcg/24h and serum cortisol of 124, 270, 103.4, 358.6 and 413 nmol/l ACTH 20, 21, 23, 28, 25 pg/mL. After 6 months of no clinical sign of hypercortisolism the patient reached to us as she noticed her striae changed, started gaining weight, lost menses and changed headache frequency. Laboratories revealed UFC was 754.6 mcg/24h and low dose DST was 751.1 nmol/l and ACTH of 70 pg/mL. We conducted another continuous 7mg dex infusion for seven hours with basal cortisol of 669.2 nmol/l, early suppression of 90.2 nmol/l (&amp;gt;50% suppression) and late suppression of 691.5 nmol/l which was compatible with CD. Additional testing was performed, with a 18F-NOTA-Octreotide and a full body CT that did not reveal an ectopic ACTH producing tumor neither an adrenal mass. Patient underwent a transsphenoidal surgery and reached remission of her hypercortisolism. Conclusion CD may be difficult to be confirmed but also it is important to consider that some cases showed cyclic activity. As far as we could acknowledged, this is the first case showing a 6-month period of normocortisolemia in a cyclic ACTH-secreting pituitary adenoma. Bibliography Biemond P, de Jong FH, Lamberts SW. Continuous dexamethasone infusion for seven hours in patients with the Cushing syndrome. A superior differential diagnostic test. Ann Intern Med. 1990 May 15;112(10): 738–42. Presentation: No date and time listed

Diagnostic workup of Cushing's syndrome.

Cushing's syndrome (CS) is a rare but detrimental endocrine disorder. Early diagnosis and prompt treatment are essential since the duration of hypercortisolism has an adverse impact on the extent of comorbidities and overall survival. The diagnostic approach involves a stepwise process that includes (1) screening and confirming the diagnosis and (2) establishing the aetiology of CS. The tests currently used to confirm the diagnosis of CS include urinary free cortisol measurements, the dexamethasone suppression test and late- night salivary cortisol or midnight serum cortisol measurements. None of these tests are ideal; all have pitfalls and require careful interpretation. Following confirmation of CS, measurement of ACTH discriminates between ACTH-dependent and non-ACTH dependent causes of CS. Adrenal imaging provides clues for the aetiology of non-ACTH dependent forms. Differentiation between the ACTH-dependent forms that involve pituitary corticotroph adenomas and ectopic ACTH sources is more complex and include pituitary MRI imaging, the high dose dexamethasone suppression test, the CRH test, bilateral inferior petrosal sinus sampling and, when required imaging modalities to detect ectopic ACTH secreting lesions. This review, which is part of a special issue on "Update of Cushing's syndrome: 100years after Minnie G" will provide an update on our current diagnostic workup for the confirmation and differential diagnosis of CS.