Parathyroid cyst, a rare cause of cystic cervical lesion. Case report.

Parathyroid cyst is a very rare abnormality. The diagnosis can be made based on ultrasound and the analysis of the aspirated cystic fluid for parathyroid hormone (PTH). We report the case of a nonfunctional parathyroid cyst in a 50-year-old female patient with an anterior neck mass. The patient was complaining of pain in the anterior cervical region, dysphagia, dyspnea and dysphonia started three weeks previously. Ultrasound demonstrated an anechoic and avascular lesion located in the left lobe of the thyroid. Fine needle aspiration (FNA) revealed a clear, colorless and watery cystic fluid, that showed a high concentration of parathyroid hormone (PTH) in both the native and the diluted content of the cyst, while serum PTH was normal, indicating a nonfunctional parathyroid cyst. The patient was in remission by percutaneous aspiration and there was no relapse of the parathyroid cyst after one-year follow-up.