Abstract
Cystic parathyroid adenoma is rare. This report presents a 48-year-old female with primary hyperparathyroidism caused by cystic parathyroid adenoma.
She was found to have hypercalcemia on laboratory examinations performed in the Department of Internal Medicine of our hospital during a search for the cause of her vertigo. Further examinations indicated a functioning parathyroid cyst. Ultrasonography and MRI scan showed that the cystic portion was sharply demarcated from the solid portion of the lesion in a parathyroid gland. The high level of plasma PTH decreased to normal after removal of the enlarged parathyroid gland. Histological examination demonstrated a secondary pseudocyst resulting from cystic degeneration of a parathyroid adenoma. Twenty-seven cases of functioning parathyroid cysts reported in the Japanese literature are reviewed. The clinical features and histological evidence of functioning parathyroid cyst are discussed.
