[Two cases of functioning parathyroid cysts]

Two cases of functioning cysts are reported. The first patient was a 48-year-old man who underwent percutaneous cyst puncture for a palpable mass in the neck at another hospital. Hypercalcemic crisis brought the patient to Koga General Hospital. The second patient was a 69-year-old woman with the complaint of discomfort in the right neck of several years duration and with a palpable mass identified on physical examination at a local hospital. Both patients had high serum calcium and parathyroid hormone (PTH) levels and were diagnosed as having functioning parathyroid cysts by imaging studies including ultrasonography, computed tomographic scan, magnetic resonance imaging and scintigraphy. After parathyroidectomy, their serum calcium and PTH levels became normal, but calcium supplement was necessary in the first patient. To our knowledge, these are the 40th and 41st cases reported in the Japanese literature.