Parathyroid cysts: description of two cases and review of the literature.

Parathyroid cysts are a relatively rare cause of neck swelling, and their anatomo-pathological and clinical features are still under debate. Two types of parathyroid cysts have been recognized: the non-functioning or essential forms, which are more frequent, and the adenomatous or functioning parathyroid cysts, which are rarer and cause hyperparathyroidism. Two cases of parathyroid cysts are reported and the treatment is described bearing in mind the various therapeutic procedures proposed in the literature. Attention is focused on pre-operative differential diagnosis from other masses, in the same area, and, to this end, the importance is stressed of assaying parathyroid hormone levels in the cystic fluid, obtained by fine-needle aspiration, and correlating these values with serum levels of the hormone.