Intrathyroidal Parathyroid Research Articles

Primary hyperparathyroidism with intrathyroidal location of parathyroid adenoma

Primary hyperparathyroidism is a common endocrine disease with high morbidity and mortality from all causes. The disease can be asymptomatic and for a long time remain undiagnosed, which leads to untimely surgical treatment, increases the risks of development and progression of severe disabling complications and worsens patients prognosis. In clinical practice there are certain difficulties in diagnosing this pathology. One of the urgent problems is the search for the source of parathyroid hormone hyperproduction, especially in case of atypical location of paraаdenoma. The most common atypical locations of altered parathyroid glands are thymus, retroor paraesophageal space, retropharyngeal space, mediastinum and thyroid gland. The frequency of intrathyroidal masses of parathyroid glands, in the thyroid parenchyma or under its capsule, ranges on average from 2 to 3%, but according to some authors can reach 18–22%. With such localization of paraadenomas there is a need for their differential diagnosis, first of all, with nodular formations of the thyroid gland. In addition, the absence of additional laboratory studies parathormone and calcium blood levels does not allow timely suspicion of the disease, and cytologic examination of the material obtained by fine-needle aspiration puncture biopsy does not allow reliable differentiation of the altered parathyroid gland. This article presents a clinical case of a patient with primary hyperparathyroidism with intrathyroidally located parathyroid adenoma, for a long time long identified as a “nodular goiter,” and provides a brief review of the methods that identify an intrathyroidally located parathyroma. Despite the abundance of diagnostic methods in visualization of intrathyroidal parathyroid glands, today the most appropriate seems to be expert ultrasound examination with assessment of the parathyroid hormone level in a washout after fine-needle aspiration, supplemented, if necessary, by scintigraphy and single-photon emission computed tomography combined with computed tomography or multispiral computed tomography.

7387 A Rare Case Of Concomitant Intrathyroidal Parathyroid Carcinoma With Osteitis Fibrosa Cystica, Masquerading As Oncocytic Thyroid Carcinoma - A Post-operative Diagnosis

Abstract Disclosure: Y. Koh: None. D.E. Chew: None. T.P. Quek: None. Introduction: Parathyroid carcinoma is a rare form of malignancy. An intrathyroidal location of parathyroid carcinoma further complicates the diagnosis as it may be mistakenly presumed to be of thyroid origin instead. We present a case report of an intrathyroidal parathyroid carcinoma which was diagnosed post-total thyroidectomy. Clinical case: A 72-year-old lady was found to have an intrathyroidal mass after presenting with unintentional weight loss and chronic constipation. Ultrasound of the neck showed a 4.0 x 2.9cm markedly hypoechoic solid mass in the mid-lower right thyroid lobe. Fine needle aspiration of the mass was suspicious for an oncocytic neoplasm. She underwent total thyroidectomy with central neck dissection for concerns of oncocytic thyroid carcinoma. Intraoperatively, a 4cm right hard intrathyroidal nodule invading into the right recurrent laryngeal nerve was observed. All 4 parathyroids were identified and preserved. Post-operatively, routine biochemistry to monitor for hypocalcemia showed hypercalcemia instead. This quickly transitioned into hypocalcemia on post-operative day 4, with biochemistry supportive of hungry bone syndrome [adjusted calcium 2.05mmol/L [normal range (NR) 2.15-2.5], phosphate 0.6mmol/L (NR 0.8-1.4), PTH 8.2pmol/L (NR 0.8-6.8), 25-OH vitamin D 18ug/L (NR 30-100)]. She was started on oral calcium carbonate, calcitriol and cholecalciferol aiming for normocalcemia. Evidence for underlying primary hyperparathyroidism were sought for, which showed osteitis fibrosa cystica, severe osteoporosis and an ossifying fibroma of the mandible, suggesting underlying hyperparathyroidism-jaw tumour-syndrome. The intra-operative histology was reported as oncocytic carcinoma with angio- and perineural invasion, presumed to be thyroid in origin. Given our suspicion of underlying primary hyperparathyroidism, we requested our pathology colleagues to perform additional immunochemical stains, which stained diffusely positive for parathyroid hormone, GATA3 but were negative for thyroglobulin, thyroid transcriptor factor-1, confirming its parathyroid origin. Her hungry bone syndrome resolved 22 weeks post-operatively. Till present (14 months post-operatively), her calcium and PTH levels remain normal and ultrasound of the neck did not reveal any evidence of recurrence. She declined genetic screening. Clinical Lesson: A high index of suspicion is required for the diagnosis of parathyroid carcinoma. In a patient who presents with constitutional symptoms and a neck mass, it is imperative to consider parathyroid disease as a differential diagnosis. A lesion with oncocytic morphology may be of parathyroid or thyroid origin, and the use of immunochemical stains can help differentiate them. Effective communication between clinicians and pathologists is essential in clinching the correct cytopathological diagnosis. Presentation: 6/3/2024

A rare coexistence of intrathyroidal parathyroid gland and papillary thyroid carcinoma in MEN1 syndrome: a clinical, diagnostic and surgical challenge.

A rare coexistence of intrathyroidal parathyroid gland and papillary thyroid carcinoma in MEN1 syndrome: a clinical, diagnostic and surgical challenge.

Incidental synchronous intrathyroidal parathyroid carcinomas and papillary thyroid microcarcinoma with compressive neck mass and primary hyperparathyroidism: case report and literature review

BackgroundParathyroid carcinoma (PC) is a rare malignancy, often diagnosed incidentally through postoperative pathological examination. The occurrence of nodular goiter, intrathyroidal parathyroid carcinoma, contralateral parathyroid adenoma (PA), and papillary thyroid microcarcinoma (PTMC) is extremely uncommon, which prompted us to report our case experience.Case presentationWe describe a 67-year-old male who presented with a cervical mass causing tracheal compression, which prompted him to seek medical advice. Based on preoperative auxiliary examination results from color Doppler ultrasound, SPECT parathyroid imaging, and blood tests, he was initially diagnosed with a suspected parathyroid adenoma and nodular goiter. Excision of the right lobe and isthmus of the thyroid, and left superior parathyroid gland was conducted, which were sent to intraoperative frozen pathological examination. During intraoperative observation, adhesion around the right thyroid lobe was discovered. Consequently, right central area lymph node dissection was performed due to suspicion of an aggressive malignant tumor. Histology and immunohistochemistry analysis revealed incidental intrathyroidal parathyroid carcinoma, contralateral parathyroid adenoma, classical papillary thyroid microcarcinoma, and nodular goiter.ConclusionParathyroid carcinoma should be highly suspected when extremely high levels of PTH and severe hypercalcemia are present, which cannot be simply explained by a preoperatively localized parathyroid adenoma, especially when suspicious malignant adhesion is found during intraoperative exploration. In cases where multifocal thyroid nodules are associated with increased uptake of 99Tc-sestamibi, the possibility of coexisting carcinomas should be considered, not only for thyroid malignancy but also for the potential presence of intrathyroidal parathyroid carcinoma.

Intrathyroidal Parathyroid Adenoma - An Incidental Diagnosis.

Aim This case report highlights the importance of preoperative assessment of calcium in all cases of thyroid surgery. Intrathyroidal parathyroid adenoma (IPA) is a rare presentation of primary hyperparathyroidism. It is caused by abnormal embryonic migration of parathyroid glands and is difficult to detect preoperatively. When diagnosed pre operatively it has good surgical outcome. Herein authors present a case of thirty-two-year lady who underwent hemithyroidectomy for colloid goitre and was detected to have intrathyroidal parathyroid adenoma (IPA) on histopathological examination.

Intrathyroidal Parathyroid Adenoma.

Intrathyroidal parathyroid adenoma is a rare anomaly with an incidence of 1.4-6%. A cause of failure in the therapeutic management of hyperparathyroidism is the ectopic localization of the adenoma, particularly intrathyroidal. This is the case of a 51-year-old patient with no particular pathological history who presented with neck pain and whose clinical examination revealed a goiter. Parathyroid myocardial perfusion imaging (MIBI) scintigraphy revealed an elective MIBI-fixing focus with an upper left polar projection compatible with a parathyroid origin. A left loboishmectomy was performed. Anatomopathological study showed a parathyroid adenoma associated with dystrophic thyroid parenchyma, with no obvious histological signs of malignancy. Post-therapeutic laboratory work-up was normalized. Parathyroid adenoma, intrathyroidal, is an uncommon lesion but may be responsible for therapeutic failure in hyperparathyroidism. MIBI parathyroid gland scintigraphy is the gold standard for the diagnosis of parathyroid ectopy.

Concurrent Intrathyroidal Parathyroid Adenoma and Papillary Thyroid Microcarcinoma: A Case Report

Papillary thyroid carcinoma (PTC) is the commonest endocrine thyroid malignancy. The concurrent incidence of intrathyroidal parathyroid adenoma and papillary thyroid carcinoma is an infrequent finding. Surgical treatment via excision is the only definitive management approach. Here in we present a case report of intrathyroid parathyroid adenoma with incidental papillary micro carcinoma in a 36 year-old-female who initially presented with osteoporosis.

The value of ultrasound in combination with 99mTc-MIBI imaging department of ultrasound medicine, for the diagnosis of ectopic parathyroid glands in the thyroid gland in patients with secondary hyperparathyroidism.

To investigate the value of preoperative ultrasound combined with 99mTc-MIBI imaging for the diagnosis of ectopic intrathyroid parathyroid gland (ETPG) in patients with secondary hyperparathyroidism (SHPT). One hundred and eleven patients with SHPT who underwent total parathyroidectomy plus forearm transplantation from January 2015 to January 2022 in the Third Hospital of Hebei Medical University were selected. All patients underwent routine preoperative ultrasonography and 99mTc-MIBI imaging, and with pathological diagnosis as the gold standard, the clinical data of ETPG patients were selected, including clinical manifestations, laboratory tests, preoperative ultrasonography and 99mTc-MIBI imaging for localization and diagnosis, intraoperative exploration and postoperative pathology, and postoperative follow-up. To analyze the ultrasound manifestations of preoperative parathyroid hyperplasia and the results of 99mTc-MIBI imaging in patients with ETPG. Among 111 patients with SHPT, there were 5 patients with ETPG, 1 male and 4 females with a mean age of (45.00 ± 5.05) years, and 6 ectopic parathyroid glands were located in the thyroid gland. The incidence of ETPG was 4.5% (5/111), 4 were detected by ultrasound, 2 were not detected with a diagnostic accuracy of 66.7% (4/6), 3 were positive for 99mTc-MIBI imaging, 3 were negative with a diagnostic accuracy of 50.0% (3/6). Among them, one was not detected by ultrasound, but was positive for 99mTc-MIBI imaging, 2 with negative 99mTc-MIBI imaging, but all were detected by ultrasound, and one with negative 99mTc-MIBI imaging was detected by ultrasound but misdiagnosed as a thyroid nodule. A total of 5 ETPGs were detected by ultrasound combined with 99mTc-MIBI imaging, with a diagnostic accuracy of 83.3% (5/6). Patients' postoperative serum calcium and serum parathyroid hormone (PTH) levels were normalized or significantly decreased from preoperative levels. Ultrasound combined with 99mTc-MIBI imaging can achieve higher accuracy than either examination alone in the preoperative localization and diagnosis of ETPG in SHPT patients.

A new histopathological location of parathyroid gland with high possibility of unintended parathyroidectomy.

Unintended parathyroidectomy occasionally happens despite meticulous capsular dissection and the histopathological location of removed parathyroid glands were traditionally classified as extracapsular, subcapsular, and intrathyroidal location. This study aimed to investigate the new histopathological location of parathyroid gland with high possibility of unintended parathyroidectomy that was difficult to be found with naked eye despite capsular dissection. This study investigated unintended parathyroidectomy that occurred in 743 patients who received thyroid surgery by reviewing pathology reports and slides. The histopathological location of unintentionally removed parathyroid glands was classified as intracapsule and extracapsule, and the intracapsular glands were further classified as completely buried in the thyroid parenchyme, partially buried, and subcapsular locations. The incidence of unintended parathyroidectomy was 12.8%. Among the 103 unintentionally removed parathyroid glands, 74 (71.8%) were found intracapsular and 29 were extracapsular. Among the intracapsular glands, 57 (55.4%) parathyroid glands were found in difficult locations such as completely buried (40.8%) and partially buried (14.6%). The partially buried parathyroid gland can act as a risk factor for unintended parathyroidectomy comparable to intrathyroidal parathyroid gland despite the surgeon's best effort with meticulous capsular dissection. However, continued advances in visualizing technique such as autofluorescence imaging may lower the chance of incidentally removed partially buried parathyroid glands in the future.

Treating intra-thyroid parathyroid adenoma by radiofrequency is a valuable alternative to hemithyroidectomy

Background Parathyroid adenoma (PA) is the most common cause of primary hyperparathyroidism (PHPT). One infrequent scenario (0.7%–6%) is represented by intra-thyroid PA (I-PA), an ectopic variant of the parathyroid gland included in the thyroid parenchyma. Radiofrequency (RF) of I-PA seems to be an excellent alternative to hemithyroidectomy for these patients. The present study aimed to report three cases of PHPT and I-PA treated with RF at two institutions. Materials and methods These two institutions share guidelines for thyroid RF. At both institutions, cases with surgical indication and difficult PA localization are discussed during thyroid multidisciplinary meetings involving all disciplines involved in managing these cases. RF was performed using a Viva RF System generator (STARMED). Ultrasound contrast evaluation was performed using a SonoVue (Bracco). All patients were followed-up by an expert endocrinologist. Results Three cases had indications for treating I-PA. All patients were proposed to undergo RF rather than hemithyroidectomy, and accepted this option. RF of I-PA was performed with a power of 30–50 W and delivering a total between 0.02 and 0.69 Kcal. The active treatment lasted just more than 1 min. Post-treatment follow-up revealed PTH and calcium normalization. Conclusion This study showed highly encouraging results in favor of treating I-PA with RF.

How often are intrathyroidal parathyroid glands a cause of primary hyperparathyroidism, and how should they be managed?

The purpose of our study was to determine the frequency and management of intrathyroidal parathyroid glands in patients with primary hyperparathyroidism and evaluate whether intrathyroidal parathyroid glands were more often superior or inferior glands. A retrospective review of the prospective parathyroid database was completed to determine the number of patients with primary hyperparathyroidism and an intrathyroidal parathyroid gland. Demographic data, laboratory and localization studies, operative management, pathology, and outcome were determined for patients with an intrathyroidal parathyroid gland and were compared with patients with an extrathyroidal parathyroid gland. From 1990-2023, 808 patients were operated on for primary hyperparathyroidism; 17 (2%) patients had an intrathyroidal parathyroid gland, an adenoma in 15 (88.2%), and a hyperplastic gland in 2(11.8%). The mean age was 53 years; 16 (94%) patients were female. Mean calcium and parathyroid hormone was 12 mg/dL and 150 pg/mL, and there were no differences from the extrathyroidal parathyroid group. Ultrasound and Sestamibi imaging were valuable in identifying an intrathyroidal parathyroid gland in 10 of 13 patients and 13 of 17 patients, respectively. Local excision was performed in 9(53%) patients and lobectomy in 8 (47%) patients. Intraoperative parathyroid hormone was measured and predictive of cure in 12 patients. The location of intrathyroidal parathyroid glands was determined in 15 patients and was inferior in 11 (73%). All patients were cured. No patient developed recurrent disease after a median 54-month follow-up. Intrathyroidal parathyroid glands are the cause of primary hyperparathyroidism in 2% of patients and are most often inferior glands. Local excision was accomplished in 53% of our patients.

A rare case of Intrathyroidal parathyroid adenoma causing refractory hypercalcaemia. A challenging diagnostic and therapeutic journey

A rare case of Intrathyroidal parathyroid adenoma causing refractory hypercalcaemia. A challenging diagnostic and therapeutic journey

Brown tumor due to primary hyperparathyroidism in a familial case: a case report

BackgroundPrimary hyperparathyroidism (PHPT) is an uncommon disorder characterised by hypercalcemia with an increased parathyroid hormone level. We reported a PHPT familial case with two subjects, a father and a daughter, and both of them had suffered from the brown tumor.Case presentationThe proband, a 43-year-old patient, developed parathyroid adenomas at the age of 15; a histologically confirmed right parathyroid adenoma was removed by parathyroidectomy; and after six months follow-up, the serum calcium level was normalised. At the age of thirty-three, a CT scan of his head and neck revealed a mass in the right maxilla, as well as PHPT (i.e., left inferior parathyroid adenoma). Then, he underwent a biopsy of an exophytic lesion in the right maxilla and was diagnosed by pathology as a brown tumor, with the serum calcium and PTH levels at 2.78 mmol/L and 221 pg/mL, respectively. Subsequently, the patient took a left inferior parathyroid microwave ablation with ultrasound guidance. After three months of follow-up, the serum calcium and PTH levels returned to normal, and the brown tumor was resolved. After three years, it mineralised as revealed in a CT scan. By the time he was 43 years old, during the 28-year follow-up period, the serum calcium and PTH levels were still within the normal range, and there was no discomfort reported. He has consistently taken calcium supplements throughout the 28 years. Since the initial diagnosis, his blood indicators of kidney function have been normal, and ultrasound showed renal calculus in the right kidney and a normal left kidney. The proband’s daughter, a 15-year-old girl, experienced left upper extremity pain for ten months. CT scan revealed a mass in the distal left radius, and a giant cell tumor was suspected. A surgical internal fixation was performed, and the pathology showed a brown tumor. Laboratory tests revealed a serum parathyroid hormone (PTH) level of 1554pg/mL, calcium level of 3.14 mmol/L, phosphorus level of 0.72 mmol/L, and alkaline phosphatase level of 1892 U/L. Given the osteitic changes and elevated levels of calcium and PTH, ultrasonography was performed, after which a mass was detected measuring 19 × 9 × 7 mm mixed with solid components and cystic fluid in the right thyroid gland. The results of 99mTc-MIBI scintigraphy confirmed the abnormal accumulation of 99mTc-MIBI in the right thyroid gland but not seen in the bilateral parathyroid glands. The patient underwent thyroidectomy, and the postoperative pathology report indicated an intra-thyroid ectopic parathyroid adenoma. The serum calcium and PTH levels became normal at 4 h after surgery. One to three months after operation, the serum calcium level was low, while the serum PTH level was high. Then, the patient was advised to take calcium supplements. Until the sixth month after the operation, the serum calcium level and serum PTH level returned to normal, and the bone pain was relieved. The patient’s blood tests for kidney function remained normal. There was no evidence of bilateral kidney disease (such as nephrolithiasis or nephrocalcinosis) detected by ultrasound scan. There were several similarities in the state of illness between these two subjects. Both the father and the daughter developed parathyroid adenomas at the age of 15, and there was no lesion in other endocrine glands. And genetic testing revealed mutations in the CDC73 genes in both father and daughter. On the other hand, there were also a few differences. The father’s first signs of brown tumor were in the right maxilla, while the daughter’s appeared in the distal left radius. The father presented pathological changes in the left and right parathyroid glands, whereas the daughter presented with an ectopic parathyroid adenoma in the right thyroid gland.ConclusionWe report a familial case in which father and daughter were diagnosed to have brown tumors due to parathyroid adenoma and ectopic parathyroid adenoma, and genetic testing revealed CDC73 gene mutations in both. Therefore, in the diagnostic and differential process of young patients having bone disease, clinicians should not only focus on the clinical manifestations of the skeleton, but also implement a comprehensive analysis of systemic symptoms, considering the possibility that the patient has familial PHPT.

SAT218 Refractory Hypocalcemia From Combined Autosomal Dominant Hypocalcemia Type 2 And Postsurgical Hypoparathyroidism

Abstract Disclosure: M. Sonmez Ince: None. F. Hannan: None. N. Esfandiari: None. M. Hussain: None. M.R. Haymart: None. R.V. Thakker: None. G.A. Clines: None. Background: Autosomal dominant hypocalcemia type 2 (ADH2), due to activating mutations in GNA11, is a rare disorder that causes hypocalcemia with low or inappropriately normal PTH. Postsurgical hypoparathyroidism (PSHP) is the most common etiology for hypoparathyroidism. The patient described was afflicted by both conditions and had persistent hypocalcemia despite aggressive management. Clinical Case: A 50-year-old female was found to have an enlarged thyroid on exam and subsequently diagnosed with papillary thyroid cancer (PTC). She underwent a total thyroidectomy without parathyroid autotransplantation since parathyroid glands were not identified during intraoperative pathologic survey. Surgical pathologic examination confirmed PTC with the identification of a single and small intrathyroidal parathyroid gland. Due to the patient’s low risk (T1N0M0), radioactive iodine ablation was not performed. Before thyroidectomy, serum corrected calcium was 6.4-8.5 mg/dL (8.6-10.3 mg/dL) and PTH was 9-21 pg/mL (10-65 pg/mL) during the previous 20 years. Following thyroidectomy, the patient had multiple emergency department visits due to hypocalcemia, hand cramping, and paresthesias. The patient was diagnosed with postsurgical hypoparathyroidism: corrected calcium 5.6-6.7 mg/dL, 24-hour urine calcium 112 mg (100-300 mg/24hour), magnesium 1.4-1.9 mg/dL (1.6-2.6 mg/dL), phosphorus 3-8.2 mg/dL (2.7-4.6 mg/dL). PTH remained <6 pg/mL. The patient was then referred to an academic endocrinology. TSH, AM cortisol, 25-vitamin D, iron, ceruloplasmin, copper, and 21-hydroxylase antibody concentrations were normal. Genetic testing revealed a pathogenic GNA11 variant (c.178C>T, p.(Arg60Cys)); no mutations were identified with CASR or AP2S1. Despite aggressive management with total daily oral calcitriol up to 12 mcg daily, calcium 8 grams, and chlorthalidone, the patient required calcium infusions thrice weekly. Despite the addition of teriparatide 20 mcg BID, the patient remained dependent on calcium infusions, with improvement after the addition of IV calcitriol. Recently, continuous teriparatide delivery was started using an Omnipod insulin pump that has significantly reduced the patient’s dependence on calcium infusions with serum calcium that are now 8-9 mg/dL. Conclusion: ADH2, due to gain-of-function mutations of GNA11, that encodes the Gα11 protein, causes life-long hypocalcemia that is often asymptomatic and undiagnosed. We report here the first documented case of combined ADH2 and PSHP. This case highlights that patients with ADH2 likely have hypoplastic parathyroid glands and that caution is required with procedures that may disrupt parathyroid gland function. Furthermore, the refractory nature of this patient’s hypocalcemia may suggest that GNA11 mutations in the kidney and skeleton reduce the effectiveness of standard hypocalcemia treatments. Presentation: Saturday, June 17, 2023

FRI691 Intrathyroidal Parathyroid Adenoma With Congenitally Absent Contralateral Thyroid Lobe Treated With Thermal Ablation

Abstract Disclosure: L. Bilandzic: None. L. Bilandzic: None. H. Korkusuz: None. We present a rare case of primary hyperthyroidism with ectopic adenoma located in the right thyroid lobe with congenitally absent left thyroid lobe which was treated with thermal ablation. A 60-year-old woman was referred to endocrinology clinic for further evaluation of her elevated total serum calcium of 11.4 mg/dL (reference range 8.5-10.5), elevated parathyroid hormone (PTH) level of 106 (10-60 pg/mL). Bone mineral densitometry showed a total T score of -2.9 in L1-L4. Other results were vitamin D 25-OH 30 ng/mL (ref. range 30 - 100), TSH 3.36 µIU/mL (ref range 0.4-5.0), eGFR 83 (normal > 59 mL/min/ 1.73 m²). She was asymptomatic and had no history of kidney stones. Other causes of hypercalcemia were refuted. Given the osteoporosis in her lumbar spine, parathyroid localization and surgery were suggested. Thyroid and parathyroid sonography demonstrated a solid hypoechoic nodule in the right thyroid lobe, 12x10x11mm, with smooth margins, no calcifications, classified as ACR TI-RADS T4. Left thyroid lobe was not appreciated and was considered to be congenitally absent since the patient did not have a history of a previous thyroid resection. Further localization studies (99mTc Sestamibi parathyroid scintigraphy and 4D-CT of the neck) did not reveal any other possible candidates for parathyroid adenomas. Eventually, a fine needle aspiration of the nodule in the right thyroid lobe was performed. PTH needle wash showed a PTH value of 633 pg/mL whereas the PTH value ≥ 100 pg/mL is suggestive of the presence of PTH secreting tissue. Given the thyroid anatomy found with this patient, a right lobe hemithyroidectomy would result with a permanent substitution dependent hypothyroidism. As an alternative, thermal ablation was presented as a treatment option for which the patient opted. She underwent the procedure in local anesthesia. Sonographic imaging of the adenoma was followed by the percutaneous insertion of the coagulation electrode. The utilized high frequency ablator was used with an output of 9 to 40 W and a frequency of 470 ± 10 kHz. There were no complications developed during or after the procedure. Two weeks after the thermal ablation, PTH level was measured at 55 pg/mL, total serum calcium at 9.5 mg/dL, TSH 1.01 µIU/mL. Sonography showed a hyperechoic nodule at the former location of the parathyroid adenoma, which was evaluated as a scar tissue. Three months after the procedure total calcium was at 9.3 mg/dL, PTH at 58 pg/mL, hence no biochemical evidence of pHPT. This is a rare case of ectopic parathyroid adenoma located in the thyroid gland with hemi agenesis of the contralateral lobe. A minimally invasive thermal ablation was performed with the goal of inactivation of the adenoma and preserving the euthyroid function. Presentation: Friday, June 16, 2023

SAT199 Intrathyroidal Parathyroid Adenomas: A Case Series

Abstract Disclosure: B.K. Bowens: None. D. LaChance: None. M.K. Shakir: None. T.D. Hoang: None. Background: Primary hyperparathyroidism (PHPT) is a relatively common condition which affects 1-7 people per 1000. However, intrathyroidal parathyroid adenomas (ITPA) have a prevalence of 1.3% to 6.7%. In this case series, we report 3 cases of ITPA. Case 1: 66-year-old male with a history of PHTP without intervention at initial diagnosis presented to Endocrinology several years after initial diagnosis due to an incidental thyroid nodule on routine CT lung cancer screening. Parathyroid hormone (PTH) level found to be 109.3 from a previous level of 80 (ref 10-55pg/mL) in the setting of mild hypercalcemia and osteopenia. Initial bedside thyroid ultrasound was suggestive of a right ITPA. Parathyroid scan, formal thyroid US and CT gated scan revealed a 1.5cm parathyroid adenoma (PA) posterior to the right superior aspect of the thyroid gland. Fine Needle Aspiration (FNA) was completed with PTH washout of 399.40 pg/mL. Right superior parathyroidectomy confirmed ITPA due to an intrathyroidal parathyroid adenoma Case 2: 44-year-old female presented with 9 months of fatigue and was diagnosed with PHPT. Her PTH level was 167 with a serum calcium of 10.9 (ref 8.5-10.4 mg/dL). CT SPECT with tech-99M sestamibi was positive for a right parathyroid adenoma. Explorative surgery did not localize parathyroid adenoma. Thyroid ultrasound revealed a 9mm hypoechoic lesion in the right inferior lobe with polar artery. FNA of this lesion was completed with PTH washout of 4737 pg/mL. Right hemi-thyroidectomy was completed with resolution of PHTP. Case 3: 54-year-old male with history of PHPT and carcinoma of the right kidney s/p nephrectomy presented with persistent hypercalcemia. Serum calcium of 10.2-11.0 mg/dL and PTH of 160-186 pg/mL. Thyroid US showed a 1.1cm hyperechoic, cystic nodule in the left inferior thyroid lobe. Sestamibi was consistent with ITPA. FNA of left thyroid mass with PTH washout of 2602 pg/mL. Parathyroidectomy with left thyroid lobectomy was completed with resolution of hypercalcemia. Discussion: PHPT is a common endocrinopathy with 85% of cases due to PAs, 15% due to parathyroid hyperplasia, and <1% due to carcinoma. ITPAs have an incidence of 1.3% to 6.7% and are due to improper embryologic migration. Sestamibi parathyroid scan allows for localization of PA and for minimally invasive procedures. Other imaging modalities include SPECT, US, SPECT-CT, and MRI. PTH washout with more than 101 pg/mL confirms the presence of parathyroid tissue or adenoma. Conclusion: This is a rare presentation of a common endocrinopathy. These patients were noted to have PHTP. Initial exploratory neck dissections did not localize. FNA and US were able to confirm IPTAs and hemi-thyroidectomy was needed for definitive management with resolution of PHTP. Presentation: Saturday, June 17, 2023

SAT198 Parathyroid Adenoma Masquerading As A Thyroid Nodule

Abstract Disclosure: A. Arida: None. M. Papaleontiou: None. N. Esfandiari: None. Background: The diagnosis of parathyroid adenomas using a neck ultrasound (US) can be challenging when not performed by an experienced radiologist. Additional methods of diagnosis have been implemented to distinguish the differential diagnosis of a nodule in the neck. Clinical Case: A 48-year-old woman with a history of type 2 diabetes, hypercalcemia, and kidney stones presented for evaluation of a lump in the neck of 5 years duration. Prior thyroid US showed a solid hypoechoic nodule superior to the left thyroid lobe measuring 2.2 x 1.2 x 1.1 cm with hypervascularity. Her first FNA biopsy of this nodule reported benign cytology 5 years ago. A parathyroid scintigraphy scan was negative. Repeat FNA biopsy of this nodule showed follicular lesion of undetermined significance (Bethesda category III). Surgical consultation was recommended but she decided to seek a second opinion. A repeat neck US identified a solid vascular 1.6 cm nodule along the anterior margin of the superior left thyroid lobe. Some vascularity was extending from the thyroid tissue into the nodule. It was noted that this may represent an extrathyroidal nodule or arise from the thyroid gland with a score of TIRADS 4. Laboratory tests confirmed primary hyperparathyroidism with an iPTH of 126 pg/mL (normal range, 10-65 pg/mL) and serum calcium of 10.9 mg/dL (normal range, 8.6-10.3 mg/dL). After normalizing vitamin D levels, these values remained elevated. A repeat FNA biopsy of this nodule showed evidence of intrathyroidal parathyroid tissue. Immunostains were performed on the cell block material from the FNA biopsy. Scattered groups of cells were positive for PTH while being negative for TTF-1. Further needle washout for iPTH measurement revealed an iPTH >2000 pg/mL confirming the diagnosis of a parathyroid adenoma. Parathyroid surgery was recommended as per guidelines. Discussion: Once primary hyperparathyroidism is confirmed, the localization of parathyroid adenoma is pursued by a neck US and/or parathyroid scintigraphy. Parathyroid glands are located in the superior poles and in the inferior poles of the thyroid gland but ectopic locations like retropharyngeal, intrathyroidal, and mediastinal are possible. Typical US appearance is oval, solid, well-circumscribed, homogenous, and hypoechoic compared to the thyroid tissue. The color Doppler shows that the blood supply enters at the center and distributes peripherally presenting a “vascular arch” pattern that helps differentiate them from other lesions such as tumors or lymph nodes where the distribution is more centralized. Further needle washout for PTH level can confirm the diagnosis of parathyroid adenoma. Once a parathyroid adenoma is confirmed, minimally invasive parathyroid surgery can be recommended if surgery is indicated. Conclusion: A needle washout for measuring PTH in an FNA biopsy sample should be recommended when it is unclear whether a nodule is a thyroid nodule or a parathyroid adenoma. Presentation: Saturday, June 17, 2023

Incidental parathyroidectomy during total thyroidectomy and functional parathyroid preservation: a retrospective cohort study

BackgroundThe published rate of incidental parathyroidectomy (IP) during thyroid surgery varies between 5.8% and 29%. The risk factors and clinical significance of postoperative transient hypocalcemia and permanent hypoparathyroidism are still debated. The aims of this study were to assess the clinical relevance of avoidable IP for transient hypocalcemia and permanent hypoparathyroidism, and to describe the risk factors for IP.MethodsThis retrospective cohort study included 1,537 patients who had a one-step total thyroidectomy in a high-volume endocrine surgery center between 2018 and 2019. Pathology reports were reviewed for incidentally removed parathyroid glands. Intrathyroidal parathyroid glands were excluded from the study. Demographic characteristics, potential risk factors, and postoperative calcium and PTH levels were compared between IP and control groups.ResultsAvoidable IP occurred in 234 (15.2%) patients. Patients with IP had a higher risk of transient hypocalcemia (17.9% vs. 11.5%, p = 0.006; odds ratio [OR] 1.68, 95% confidence interval [95% CI]1.16–2.45) and permanent hypoparathyroidism (4.7% vs. 1.6%, p = 0.002; OR 3.01, 95% CI 1.29–6.63) than patients without IP. Multivariate analysis showed that central lymph node dissection (CLND) and incidental removal of thymus tissue were independent risk factors for IP (OR 4.83, 95% CI 2.71–8.86, p < 0.001 and OR 1.72, 95% CI 1.02–2.82, p = 0.038).ConclusionsPatients with IP were more likely to develop transient hypocalcemia and permanent hypoparathyroidism, indicating the clinical significance of avoidable IP for patients and the need for raising awareness among surgeons. Patients undergoing CLND are at a higher risk for IP, and should be adequately informed and treated. Any removal of thymus tissue should be avoided during CLND.

WTP2.3 Incidence of intrathyroid parathyroid adenoma - last 9 years in a teaching hospital

Abstract Aim The incidence of intrathyroid parathyroid adenoma (iTPA) is estimated to be 0.7-5.7% of hyperparathyroidism cases. Thyroid lobectomies may be performed when an adenoma cannot be clearly identified and isolated. We aimed to review the incidence of iTPA and outcomes after surgery within our practice. Methods We retrospectively reviewed consecutive parathyroidectomies performed by two experienced upper gastrointestinal surgeons (VS and PT) in a teaching hospital between April 2013 and December 2022. Preoperative radiological imaging was reviewed, and cases of iTPAs were diagnosed intraoperatively and on histopathology. These were further evaluated to review the outcomes after surgery. Results Total of 211 parathyroidectomy surgeries were performed, 11 (5.2%) of which were found to be iTPAs. These were confirmed on histopathology. Median age of patient cohort was 57±13 years. Patients were predominantly female (n=10, 90.9%). None underwent previous neck exploration. There was radiological (SPECT and Ultrasound) suspicion of iTPAs in 3 (1.4%) cases; peri-operative decision was made to explore for iTPA in the remaining 8 cases. 9/11 (81.8%) patients had hemithyroidectomy performed; in the remaining two cases, adenoma was successfully isolated from thyroid tissue and resected. Preoperative methylene blue infusion was utilised in all cases, of which uptake was evident in 8 (72.7%) cases. Calcium normalised in all patients postoperatively and none required further neck exploration. Conclusion Our 9-year series of parathyroid surgery revealed 5.2% incidence of iTPA, the majority of which was diagnosed intraoperatively. Diagnosis of iTPA should be considered if there is suspicion on radiological imaging and where no obvious adenoma is identified after full neck exploration.

A Case of Intra-thyroidal Parathyroid Adenoma Confirmed by Intraoperative Near-infrared Autofluorescence

In general, the anatomical location and number of parathyroid glands are well known, but they are often found in a variety of locations, making it difficult to find parathyroid glands during surgery. Besides Intra-thyroidal parathyroid adenoma is extremely rare case, and it is harder to identify in surgery. We encountered a 51-year-old patient with a thyroid nodule. The results of the additional blood test and the Tc-99m MIBI were combined to determine that the left lower lobe parathyroid adenoma was highly likely. This patient was treated with left thyroid lobectomy with parathyroid identification using Near-infrared (NIR) imaging. Afterwards, the biopsy confirmed that it was a parathyroid adenoma, and has since been monitored through outpatient observation without any problem. We present this rare case with a review of related literatures.