Parathyroid cysts.

Parathyroid cysts are relatively uncommon lesions. Approximately 200 cases have been reported. Despite their location in the region of the thyroid gland, they have not previously been discussed in the otolaryngologic literature. They arise from remnants of the pharyngeal pouch or as a result of cystic degeneration of a parathyroid adenoma. A case of a parathyroid cyst occurring in a 13-year-old female is presented. This is the youngest case ever reported. Fine needle aspiration of an anterior neck mass yielded clear fluid, a finding highly suggestive of a parathyroid cyst. Radioimmunoassay of the fluid demonstrated a high level of parathormone and low level of thyroglobulin concentration, thereby confirming the diagnosis. In this case, which was diagnosed by FNA, the need for a trial of thyroid hormone suppression or hemithyroidectomy was obviated.