Endocrine Abstracts

Introduction: 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 the cervical masses.

Methods: We report the case of a 37-year-old man admitted to the hospital with a neck mass of 48 mm.

Results: Our patient presented with neck pain and an hipoechogenic nodule on ultrasound (US) on the left side of the neck adjacent to the lower pole of the left thyroid lobe. An US-guided fine-needle aspiration was performed and follicular cells where described. Measurement of TSH, T4L and AbTPO had a normal result. Given the suspicion of thyroid nodule >4 cm surgical treatment was decided. While waiting for surgery an US was performed and we observed markedly reduction on the size of the nodule (28 mm) and the radiologist suggested the possibility of a parathyroid adenoma. Our patient referred prior episodes of nephrolitisis a few years ago and that he had been told to had high serum calcium levels but did not undergo further studies. We measured PTHi levels and Calcium (100,5 pg/ml; 10 mg/dl) showing a normocalcemic hyperparathyroidism. Left thyroid lobectomy was performed showing a normal left thyroid lobe, a parathyroid cyst and ectopic thymus.

After nodule resection PTHi levels went back to normal and calcium levels remain less than 10 mg/dl.

Conclusion: PCs are rare lesions and often considered as thyroid cysts. Diagnosis is best made by monitoring serum calcium levels and sending cyst fluid for PTH analysis. Therefore, PCs must be included and be remembered within the differential diagnosis of all neck masses.