Parathyroid tumors in the 5th edition of the WHO Classification of Tumors of the Endocrine Organs.

The diagnosis of pathological conditions of the parathyroid glands is the answer to clinically more frequently detected hypercalcemic conditions, including MEN syndromes. In routine biopsy practice, enlarged bodies are also a differential diagnosis for the diagnosis of thyroid nodules. In the chapter of parathyroid tumors, the 5th edition of the WHO classification brings changes influenced similarly to other endocrine organs by the increase in genetic information. At the terminological level, the concept of hyperplasia has been narrowed down to secondary hyperplasia, most of the previously primary hyperplasias are referred to as multiglandular parathyroid disease due to evidence of multiglandular clonal proliferations. The term atypical parathyroid tumor replacing atypical adenoma is newly introduced - the uncertain biological behaviour is emphasized. The basic examination includes parafibromin immunohis- tochemistry, the deficiency of parafibromin being an indicator of an inactivating CDC73 mutation and an increased risk of familial forms, or MEN. Methodologically, refinements are introduced in the quantification of mitotic activity per 10 mm2. Oncocytic subtypes have an arbitrarily declared threshold of more than 75% oncocytes. The definition of lipoadenoma (multiplication of both components, more than 50% of adipose tissue in the tumor) is similarly specified. The diagnosis of cancer remains histopathological with unequivocal evidence of invasion, or microscopically verified metastasis.

Incidentally detected follicular thyroid carcinoma mimicking parathyroid adenoma on Tc-99m MIBI scan: A case report.

RATIONALE: Primary hyperparathyroidism, though relatively prevalent among endocrine disorders, affecting 1% of the general population, often presents diagnostic challenges. Given its potential to precipitate severe complications including nephrolithiasis and fractures, timely diagnosis, and effective management are crucial. PATIENT CONCERNS: A 38-year-old woman with hypercalcemia was referred to the Department of Nuclear Medicine for a Tc-99m MIBI scan. DIAGNOSES: Tc-99m MIBI scan showed focal increased uptake in the left thyroid gland area, initially suggesting a parathyroid adenoma. Further examination using SPECT/CT revealed a nodular lesion within the left thyroid gland showing high Tc-99m MIBI uptake. INTERVENTIONS: Left thyroid lumpectomy confirmed the lesion as follicular thyroid carcinoma. On the second Tc-99m MIBI scan conducted after total thyroidectomy, a parathyroid adenoma was eventually detected in the right lower area, enabling the subsequent appropriate treatment, a right lower parathyroidectomy. OUTCOMES: Thirteen days after the parathyroidectomy, serum levels of total calcium and parathyroid hormone returned to normal. Furthermore, bone mineral density evaluated using DEXA remained within the expected range for her age even after 14 months. LESSONS: When interpreting the Tc-99m MIBI scan, it is essential to keep in mind that various tumors rich in mitochondria, such as thyroid carcinoma, could show a high uptake of Tc-99m MIBI.

Multiple pathological fractures and muscle atrophy caused by a parathyroid carcinoma with postoperative hungry bone syndrome: A case report.

BACKGROUND: Parathyroid carcinoma (PC) is a rare endocrine malignancy causing pathological changes such as abnormal bone metabolism, elevated serum calcium, and impaired renal function, and uncontrollable hypercalcemia is the main cause of death in PC patients. The diagnosis of PC is challenging and relying on postoperative histopathology. Radical surgery at the first time is the only effective therapy to cure PC. Hungry bone syndrome (HBS) is a relatively uncommon complication of parathyroidectomy characterized by profound and prolonged hypocalcemia, timely electrolyte monitoring and alternative interventional protocols can prevent symptomatic hypocalcemia. CASE: A 57-year-old man presented with multiple pathological fractures and muscle atrophy as the main symptoms accompanied by bone pain, hypercalcemia, elevated parathyroid hormone (PTH), and an enlarged left-sided neck mass. After consultation of multidisciplinary team, he was treated conservatively with plaster bandage fixation and infusion of intravenous zoledronic acid; and then complete resection of parathyroid mass + removal of involved tissue structures + left thyroid and isthmus lobectomy + lymph node dissection in the VI region in left neck were performed. The postoperative histopathology suggested a diagnosis of parathyroid carcinoma. Calcium and fluid supplementation and oral levothyroxine tablets were given postoperatively. Unexpectedly, the patient's PTH level decreased rapidly at 24 h postoperative, and serum calcium and phosphorus decreased continuously, and he felt numb around perioral sites and fingertips, which considered to be postoperative HBS complicated by parathyroidectomy. Then, a large amount of calcium supplementation and vitamin D were given timely and the patient got better at 1 month postoperatively. At 9-month postoperative, his bone pain and fatigue were significantly relieved compared with before with calcium, phosphorus, and PTH levels at normal range. CONCLUSION: The possibility of parathyroid disease, particularly PC, should be considered in the presence of multiple pathological fractures, muscle atrophy, generalized bone pain, hypercalcemia, and clear neck mass. Radical resection of the tumor lesions at the first surgery is a key element affecting the prognosis of PC, and the effective management of preoperative hypercalcemia and postoperative HBS is also of great significance for improving prognosis.

Primary hyperparathyroidism in pregnancy: a case report highlighting uncommon complication.

Primary hyperparathyroidism (PHPT) is characterized by elevated levels of calcium and parathyroid hormone (PTH). However, the interpretation of diagnostic tests, such as serum calcium and PTH levels, is complex in pregnant women. The aim of this report is to present a case of PHTP in a pregnant adolescent, with a special emphasis on an uncommon complication, as well as diagnostic and treatment strategies. A 17-year-old pregnant female presented with hyperemesis gravidarum and neurological symptoms, leading to the diagnosis of cerebral venous thrombosis. Further investigations revealed hypercalcemia and persistently elevated PTH levels, consistent with PHPT. After localization studies, the patient underwent an emergency parathyroidectomy with a diagnosis of parathyroid adenoma. During follow-up, intrauterine growth restriction and severe preeclampsia developed, necessitating an emergency cesarean section. Both the mother and neonate had favorable outcomes. PHPT is an infrequent condition in the pregnant population, and its diagnosis can be challenging due to the overlap of symptoms with normal physiological changes during pregnancy. The occurrence of uncommon complications, such as thrombotic phenomena, highlights the need for a comprehensive approach to ensure early detection and management. In most cases, parathyroidectomy is the treatment of choice.

El hiperparatiroidismo primario (HPTP) se caracteriza por niveles elevados de calcio y hormona paratiroidea (PTH). Sin embargo, la interpretación de pruebas diagnósticas, como los niveles de calcio sérico y PTH, es compleja en mujeres embarazadas. El objetivo de este reporte es presentar un caso de HPTP en una adolescente embarazada, con especial hincapié en una complicación infrecuente, así como en las estrategias diagnósticas y de tratamiento. Una mujer embarazada de 17 años presentó hiperémesis gravídica y síntomas neurológicos, lo que llevó al diagnóstico de trombosis venosa cerebral. Posteriores investigaciones revelaron hipercalcemia y niveles persistentemente elevados de PTH, consistentes con HPTP. Tras la realización de estudios de localización, la paciente fue sometida a una paratiroidectomía de emergencia con diagnóstico de adenoma de paratiroides. Durante el seguimiento, se desarrolló restricción del crecimiento intrauterino y preeclampsia grave, lo que resultó en la necesidad de realizar una cesárea de emergencia. Tanto la madre como el neonato evolucionaron favorablemente. El HPTP es una condición infrecuente en la población embarazada y su diagnóstico puede ser desafiante por la superposición de síntomas con los cambios fisiológicos normales del embarazo. La aparición de complicaciones infrecuentes, como fenómenos trombóticos, resalta la necesidad de un abordaje integral para garantizar la detección y el manejo temprano. En la mayoría de los casos, la paratiroidectomía es el tratamiento de elección.

Atypical parathyroid adenoma with severe bone manifestations in early adolescence.

This is a case of primary hyperparathyroidism in a female teenager with multiple fractures and severe bone manifestations. The histopathology revealed atypical parathyroid adenoma, an exceedingly rare form of hyperparathyroidism; its main differential diagnosis is parathyroid carcinoma, as it shares both clinical and histological characteristics with it, in addition to its still uncertain malignant potential.

Preoperative Lateralization and Diagnostic Value of Selective Bilateral Internal Jugular Venous Sampling in Primary Hyperparathyroidism: Single-Center Experience.

Background and Objectives: Primary hyperparathyroidism (pHPT) is a common endocrine disorder caused by excessive production of parathyroid hormone (PTH) leading to elevated calcium levels. Diagnosis is primarily based on biochemical evaluation, and surgery is the curative treatment. Imaging techniques like ultrasound and Tc-99m Sestamibi scintigraphy are used for localization, but selective Internal Jugular Venous (SVS) becomes valuable in cases of inconclusive or conflicting results. This study evaluated the diagnostic efficacy of SVS for localizing parathyroid adenomas in cases where non-invasive radiological diagnostic methods yielded inconclusive results or negative findings despite clinical symptoms suggestive of pHPT. Materials and Methods: In this retrospective study, a total of 28 patients diagnosed with pHPT underwent SVS at a tertiary center known for receiving referrals from 2017 to 2022. The diagnoses were confirmed through biochemical analysis. The SVS results in 22 patients were compared with non-invasive imaging methods, including ultrasound, scintigraphy, and computed tomography with/without contrast material. SVS was indicated when at least two non-invasive diagnostic procedures failed to clearly localize the parathyroid glands or provided ambiguous results. Results: SVS demonstrated higher sensitivity for localizing parathyroid adenomas compared to non-invasive imaging methods, accurately lateralizing the adenoma in 68.18% of cases. Among the SVS findings, 31.8% of patients had negative results, with 9.1% not having clinically proven parathyroid adenoma, while 22.7% had false negative SVS findings but were later confirmed to have adenoma during surgery. Ultrasound correctly identified the location in 45.45% of cases, CT in 27.27%, and scintigraphy in 40.9%. Conclusions: SVS is a valuable diagnostic tool for accurately localizing parathyroid adenomas in patients with inconclusive non-invasive imaging results. It aids in targeted surgical interventions, contributing to improved management and treatment outcomes in primary hyperparathyroidism.

Insights into Hyperparathyroidism-Jaw Tumour Syndrome: From Endocrine Acumen to the Spectrum of CDC73 Gene and Parafibromin-Deficient Tumours.

A total of 1 out of 10 patients with primary hyperparathyroidism (PHP) presents an underlying genetic form, such as multiple endocrine neoplasia types 1, 2A, etc., as well as hyperparathyroidism-jaw tumour syndrome (HJT). We aimed to summarise the recent data, thus raising more awareness regarding HJT, from the clinical perspective of PHP in association with the challenges and pitfalls of CDC73 genetic testing and parafibromin staining. This narrative review included a sample-focused analysis from the past decade according to a PubMed search. We identified 17 original human studies (≥4 patients per article). The mean age at disease onset was between 20.8 and 39.5 years, while the largest study found that 71% of patients had HJT recognised before the age of 30. Males and females seemed to be equally affected, in contrast with sporadic PHP. PHP represented the central manifestation of HJT, occurring as the first manifestation in up to 85% of HJT cases. A biochemistry panel found a mean serum calcium level above the level of 12 mg/dL in PHP. PTH was elevated in HJT as well, with average values of at least 236.6 pg/mL. The most frequent pathological type in PHP was a parathyroid adenoma, but the incidence of a parathyroid carcinoma was much higher than in non-HJT cases (15% of all parathyroid tumours), with the diagnosis being established between the age of 15 and 37.5. In some families up to 85% of carriers suffered from a parathyroid carcinoma thus indicating that certain CDC73 pathogenic variants may harbour a higher risk. An important issue in HJT was represented by the parafibromin profile in the parathyroid tumours since in HJT both parathyroid adenomas and carcinomas might display a deficient immunoreactivity. Another frequent manifestation in HJT was ossifying fibromas of the jaw (affecting 5.4% to 50% of patients; the largest study found a prevalence of 15.4%). HJT was associated with a wide variety of kidney lesion (mostly: kidney cysts, with a prevalence of up to 75%, and renal tumours involved in 19% of patients). The risk of uterine lesions seemed increased in HJT, especially with concern to leiomyomas, adenofibromas, and adenomyosis. The underlying pathogenic mechanisms and the involvement of CDC73 pathogenic variants and parafibromin expression are yet to be explored. Currently, the heterogeneous expression of parafibromin status and, the wide spectrum of CDC73 mutations including the variety of clinical presentations in HJT, make it difficult to predict the phenotype based on the genotype. The central role of HJT-PHP is, however, the main clinical element, while the elevated risk of parathyroid carcinoma requires a special awareness.

Fine needle aspiration biopsy of parathyroid; is it meaningful? A cytologic study of 81 cases with histological and clinical correlations.

BACKGROUND: Recognizing the parathyroid gland and distinguishing the parathyroid from thyroid lesions in fine needle aspiration (FNA) is challenging. This study aimed to identify cytomorphologic features suggestive of parathyroid origin and to assess the utility of cytopathology in conjunction with ancillary tests in the identification of parathyroid glands. MATERIALS AND METHODS: Ultrasound (US) guided FNA of parathyroid gland and lesions in 81 patients were reviewed concerning clinical history and correlated to histopathologic findings in available cases. FNA smears were evaluated for cellularity, architectural patterns, cellular and nuclear features, and background of the smears. In 78 cases, FNA was supplemented by a measurement of parathormone (PTH) levels in the needle washout fluid (FNA-PTH assay) and/or GATA3/PTH/chromogranin-A immunostainings. RESULTS: Sixty-four cases were diagnosed cytologically as parathyroid lesions in conjunction with FNA-PTH assay and/or immunocytochemical examinations. In an additional nine cases, a diagnosis of parathyroid lesions was rendered after repeated FNA with FNA-PTH assay. The histolopathologic diagnosis of surgically excised cases (n = 75) included parathyroid adenoma (60 cases), atypical parathyroid adenoma (4 cases), parathyroid hyperplasia (10 cases), and parathyroid carcinoma (1 case). Major cytological findings of parathyroid tissue included high cellularity, scattered naked nuclei, cribriform and three-dimensional clusters, stippled chromatin, and oxyphilic cytoplasm while papillary pattern or colloid-like material was identified in three cases respectively. No nuclear grooves or inclusions were seen in any case. CONCLUSIONS: High cellularity scattered naked nuclei, cribriform and three-dimensional patterns, stippled chromatin and oxyphilic cytoplasm are cytomorphologic features that favour parathyroid origin. A combination of these features with FNA-PTH assay and/or GATA3, PTH, and chromogranin-A immunostainings on cytologic specimens aid in the identification of parathyroid glands and the distinguishing of parathyroid from thyroid lesions.

Comparing accuracy of machine learning approaches to identifying parathyroid adenomas: Lessons and new directions.

PURPOSE: The purpose of this investigation is to understand the accuracy of machine learning techniques to detect biopsy-proven adenomas from similar appearing lymph nodes and factors that influence accuracy by comparing support vector machine (SVM) and bidirectional Long short-term memory (Bi-LSTM) analyses. This will provide greater insight into how these tools could integrate multidimensional data and aid the detection of parathyroid adenomas consistently and accurately. METHODS: Ninety-nine patients were identified; 93 4D-CTs of patients with pathology-proven parathyroid adenomas were reviewed; 94 parathyroid adenomas and 112 lymph nodes were analyzed. A 2D slice through the lesions in each phase was used to perform sequence classification with ResNet50 as the pre-trained network to construct the Bi-LSTM model, and the mean enhancement curves were used to form an SVM model. The model characteristics and accuracy were calculated for the training and validation data sets. RESULTS: On the training data, the area under the curve (AUC) of the Bi-LSTM was 0.99, while the SVM was 0.95 and statistically significant on the DeLong test. The overall accuracy of the Bi-LSTM on the validation data set was 92 %, while the SVM was 88 %. The accuracy for parathyroid adenomas specifically was 93 % for the Bi-LSTM and 83 % for the SVM model. CONCLUSION: Enhancement characteristics are a distinguishing feature that accurately identifies parathyroid adenomas alone. The Bi-LSTM performs statistically better in identifying parathyroid adenomas than the SVM analysis when using both morphologic and enhancement information to distinguish between parathyroid adenomas and lymph nodes. SUMMARY STATEMENT: The Bi-LSTM more accurately identifies parathyroid adenomas than the SVM analysis, which uses both morphologic and enhancement information to distinguish between parathyroid adenomas and lymph nodes, performs statistically better.

Delayed diagnosis of parathyroid cancer manifested with pubic bone lesions and chronic kidney failure. Tricks and pitfalls of management.

INTRODUCTION: Parathyroid cancer (PTC) is an extremely rare malignancy with an incidence of 5.7 per 10 million people. The exact preoperative or intraoperative diagnosis is difficult, but of paramount importance, because resection with negative margins is the only effective treatment. CASE REPORT: A 46-years-old female was referred from another hospital with a diagnosis of "hyper-functioning thyroid nodule", based on the ultrasound showing a lesion of the right thyroid lobe and elevated FT4. At the admission, she had severe pain in the right inguinal area, fatigue, muscle weakness, and excessive diuresis. The blood assay demonstrated serum calcium of 4.02 mmol/l, parathyroid hormone of 1433.2 pg/ml, FT4 of 17.49 pmol/l, creatinine of 296 µmol/l. CT showed a tumor of the right thyroid lobe with a size of 2.5. A right lobectomy was performed. Right parathyroid glands were not found. Because of the constellation for hyperparathyroidism and suspicion of parathyroid malignancy ipsilateral and central lymph node dissection and partial removal of the right sternothyroid muscle were performed, which correlated with a significant intraoperative drop in the parathyroid hormone. Three months later, a re-resection was performed because of SPECT-CT evidence for residual parathyroid tissue. CONCLUSION: The timely diagnosis of PTC is a prerequisite for a good outcome. The best preoperative indicators are serum parathyroid hormone > 4 times above the upper limit, serum calcium > 14 mg/dL, a palpable neck mass, and a local invasion found intraoperatively. The only curative treatment is the complete removal of the tumor with a negative margin. KEY WORDS: Delayed diagnosis, Hyperparathyroidism, Parathyroid cancer, Surgery.

Parathyroid carcinoma in a patient with primary hyperparathyroidism mimicking parathyroid adenoma.

Primary hyperparathyroidism caused by parathyroid carcinoma is extremely rare. Clinically, it is very challenging to differentiate between parathyroid carcinoma and adenoma. The correct diagnosis is made based on the histopathology of the resection specimen. This case report presents a woman in her 40s with body aches, knee joint pain, and fatigue, along with chronic kidney disease. Ultrasonography revealed a large hyperechoic lesion in the left parathyroid gland. Serum calcium, parathyroid hormone, urea, and creatinine levels were increased. The inferior parathyroid gland was surgically removed, and histopathological evaluation confirmed a diagnosis of parathyroid carcinoma. Unfortunately, many patients do not undergo complete resection due to a lack of a correct diagnosis during the initial surgery.

Utility of parathyroid hormone immunocytochemistry in fine needle aspiration diagnosis of parathyroid tissue.

OBJECTIVE: The cytomorphological features of parathyroid tissue (PTT) may overlap with those of thyroid lesions, thus posing a diagnostic challenge. In this retrospective study, we reviewed our institutional experience in using parathyroid hormone (PTH) immunocytochemistry (ICC) to substantiate the diagnosis of PTT on fine needle aspiration (FNA). METHODS: Our pathology database was searched for FNA cases in which PTH ICC was performed between 1 January 2015 and 31 March 2022. PTH ICC was performed on a ThinPrep slide in cases with a clinical suspicion of PTT or with cytomorphological features raising the possibility of PTT. Patients' clinicopathological characteristics, PTH ICC results, cytological diagnoses, and surgical follow-ups, if available, were reviewed and analysed. RESULTS: The study cohort included 103 cases clinically designated as thyroid (n = 85, 82.5%), parathyroid (n = 11, 10.7%) and neck soft tissue (n = 7, 6.8%). PTH immunostaining was negative, positive, and indeterminate in 53 (51.5%), 27 (26.2%), and 23 (22.3%) cases, respectively. Surgical follow-up was available in 27 (26.2%) cases, including 17 thyroid lesions and 10 PTT cases. All positive PTH cases were confirmed to be PTT, while all but one of the negative PTH cases were non-PTT on follow-up. The calculated sensitivity, specificity, positive and negative predictive values were 85.7%, 100%, 100% and 93.3%, respectively. CONCLUSION: Our study demonstrates that PTH ICC performed on additional ThinPrep slides is a valuable adjunct test in FNA samples with a differential diagnosis of PTT vs non-PTT. Low cellularity may be a limiting factor in the accurate assessment of PTH by ICC.

Approach to the Patient With Parathyroid Carcinoma.

Parathyroid carcinoma (PC) is usually associated with severe symptomatic primary hyperparathyroidism (PHPT) and accounts for less than 1% of all cases of PHPT and approximately 0.005% of all cancers. PC most commonly occurs as a sporadic disease and somatic CDC73 mutations can be detected in up to 80% of cases. Approximately 30% of patients harbor a germline mutation of the CDC73 gene. Preoperative diagnosis of PC is difficult because no disease-specific markers are available, and PC should be suspected in patients with severe hypercalcemia and end-organ complications. The diagnosis is based on the evidence of invasive tumor growth at histology and/or metastases. En bloc resection of the tumor, together with the ipsilateral thyroid lobe and adjacent structures, should be performed by an experienced surgeon when PC is suspected. This surgical approach reduces the risk of recurrence and metastasis and offers the highest chance of cure. Nonetheless, PC has a recurrence rate of 40% to 60% and, if feasible, multiple surgical procedures should be performed. When surgery is no longer an option, medical treatment is aimed to reduce hypercalcemia and target organ complications. Targeted agents have been effectively used in a few cases. We describe herein a patient with severe PHPT due to PC and provide a systematic diagnostic and treatment approach. A thorough review of the medical history, a typical clinical and biochemical phenotype and, in some cases, the revision of the histological examination provide the clues for the diagnosis of PC.

Parathyroid carcinoma: impact of preoperative diagnosis on the choice of surgical procedure.

The operative procedure in the surgical treatment of parathyroid carcinoma differs from that of benign hyperparathyroidism. However, preoperative differentiation is often difficult. This study elucidated how clinicians diagnose parathyroid carcinoma and the relationship between preoperative diagnosis and the operative course. Using a retrospective chart review, twenty cases of parathyroid carcinoma from nine participating centers were examined. In 11 cases with preoperative suspicion of malignancy, at least one of these three features was found: elevated serum calcium level (>14 mg/dL), palpable mass, and irregular margin on ultrasonography. Although an intact parathyroid hormone (iPTH) threshold to suspect malignancy has not been established, six cases showed marked iPTH elevation exceeding 8.0 times the upper limit of normal. One case was excluded from analysis due to hemodialysis. Compared with the four cases that showed calcium elevation, the iPTH threshold might represent better sensitivity. Among 9 cases of benign preoperative diagnosis, six cases were performed with pericapsular resection. In three cases where malignancy was suspected in the middle of the operation, the recommended en bloc resection with ipsilateral thyroid lobectomy was not performed but a parathyroidectomy with surrounding soft tissue. In contrast, 10 preoperatively suspected cases underwent en bloc resection, and one case underwent pericapsular resection followed by supplementary ipsilateral hemithyroidectomy due to the uncertain pre- and intraoperative findings to determine the diagnosis. In conclusion, the surgical procedure for parathyroid carcinoma strongly depends on the preoperative diagnosis. The presence of excessive iPTH levels might contribute to improved preoperative diagnostic sensitivity for parathyroid carcinoma.

Reticular fibre structure in the differential diagnosis of parathyroid neoplasms.

BACKGROUND: To investigate the characteristics of reticular fibre structure (RFS) in parathyroid adenoma (PTA), atypical parathyroid tumour (APT), and parathyroid carcinoma (PTC), and to assess its value as a diagnostic indicator. METHODS: Clinical data and pathological specimens of patients with PTA, APT or PTC were collected. Reticular fibre staining was performed to observe the characteristics of RFS. This study evaluated the incidence of RFS destruction in parathyroid tumours, compared RFS destruction between primary PTC and recurrent and metastatic PTC, and explored the association between RFS destruction and clinicopathological features of APT and primary PTC. RESULTS: Reticular fibre staining was performed in 50 patients with PTA, 25 patients with APT, and 36 patients with PTC. In PTA cases, a delicate RFS was observed. In both the APT and PTC groups, incomplete RFS areas were observed. The incidence of RFS destruction was different among the PTA, APT, and PTC groups (P < 0.001, χ2-test), at 0% (0/50), 44% (11/25), and 86% (31/36), respectively. When differentiating PTC from APT, the sensitivity and specificity of RFS destruction were 81% and 56%, respectively. The incidence of RFS destruction was 73% (8/11) in the primary PTC group and 92% (23/25) in the recurrent and metastatic PTC groups. In both the APT group and primary PTC group, no correlation was found between RFS destruction and clinicopathological features. CONCLUSION: RFS destruction may indicate that parathyroid tumours have unfavourable biological behaviours.Reticular fibre staining may be a valuable tool for improving the diagnostic accuracy in parathyroid tumours.

Selective venous sampling in primary hyperparathyroidism caused by ectopic parathyroid gland: a case report and literature review.

BACKGROUND: As an invasive technique, selective venous sampling (SVS) is considered a useful method to identify a lesion's location to increase the success rate of secondary surgery in patients with primary hyperparathyroidism (pHPT) caused by ectopic parathyroid adenomas. CASE PRESENTATION: We present a case of post-surgical persistent hypercalcemia and elevated parathyroid hormone (PTH) levels in a 44-year-old woman with previously undetected parathyroid adenoma. An SVS was then performed for further localization of the adenoma, as other non-invasive methods showed negative results. After SVS, an ectopic adenoma was suspected in the sheath of the left carotid artery, previously considered as a schwannoma, and was pathologically confirmed after the second operation. Postoperatively, the patient's symptoms disappeared and serum levels of PTH and calcium normalized. CONCLUSIONS: SVS can provide precise diagnosis and accurate positioning before re-operation in patients with pHPT.