S-413 Giant functioning parathyroid cyst presenting with exertional dyspnea and mild dysphagia = S-413 Giant functioning parathyroid cyst presenting with exertional dyspnea and mild dysphagia

다국어 초록 (Multilingual Abstract)

Background: The differential diagnosis of cystic cervical masses includes thyroid cyst, thymic cyst, thyroglossal duct cyst, branchial cleft cyst, bronchogenic cyst, lymphangioma, and parathyroid cyst (PC). PC is one of the less common causes of cervical masses. Large PCs can manifest with compressive symptoms of the surrounding tissues. Functioning parathyroid cysts are a rare cause of primary hyperparathyroidism and are often mistaken for thyroid cysts. We report a case where a functioning parathyroid cyst presented as a mediastinal mass to emphasize the potential pitfalls associated with their diagnosis and management.?Case: A 59-year-old male patient visited our clinic for an assessment of dyspnea on exertion and mild dysphagia, symptoms that had begun 6 months prior. Chest computed tomography and neck ultrasound scanning revealed a large mediastinal cystic mass of approximately 10.8 × 5.1 cm in size, located inferior to the left thyroid lobe, causing right-lateral displacement of the large vessels, trachea, and esophagus. We performed fine needle aspiration for the cystic mass, wherein we aspirated approximately 100 cc of fluid with the appearance of old blood and tiny crystals. We also measured the parathyroid hormone (PTH) level of the aspirated fluid to be ＞5000 pg/mL, suggesting that the fluid originated from the parathyroid gland. The patient presented with primary hyperparathyroidism and elevated levels of calcium and PTH. He subsequently underwent successful parathyroidectomy without any postoperative morbidity, which resulted in complete clinical resolution of the presenting symptoms.?Conclusions: The present study reported the case of a man with a giant functional PC extending from the lower neck to the superior mediastinum. Fine needle aspiration and the detection of increased levels of PTH or thyroglobulin in the fluid of the cyst is a valuable diagnostic tool to confirm cystic neck lesions. Functional hyperparathyroidism should always be considered when parathyroid cyst is confirmed, with surgical excision being the treatment of choice in functioning giant PC.