Endocrine Abstracts

Introduction: Parathyroid cyst is a very rare abnormality, representing 0.6% of all thyroid and parathyroid lesions. The diagnosis can be made on the basis of sonography and analysis of aspirated cystic fluid for parathyroid hormone. Parathyroid cysts are divided in two groups: functional (associated with clinical hyperparathyroidism) and non-functional. In the case of non-functional parathyroid cysts, fine needle aspiration is the elective treatment, but for functional parathyroid cysts, surgery is the recommended approach.

Case report: We report the case of a big, non-functional, 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 accompanying a cervical mass rapidly developed in the left cervical region. Sonography showed an anechoic and a vascular lesion of 20 ml, located in the left lobe of the thyroid. The rapid development of the cyst suggested a blood cyst but the fine needle aspiration (FNA) revealed a clear colourless and watery fluid, suggesting a parathyroid cyst. In fact, the fluid 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 non-functional parathyroid cyst. The patient was cured by percutaneous aspiration and there was no relapse of the parathyroid cyst after 1 year follow-up.

Conclusion: The case illustrates a very rare cause of cystic lesion in the thyroid area and its cure by percutaneous aspiration.