Eleven cases of nonfunctioning parathyroid cyst--significance of needle aspiration in diagnosis and management.

Eleven cases of nonfunctioning parathyroid cyst are reported. Ultrasonography revealed the cystic nature of the asymptomatic lump in the neck. Clear watery fluid obtained by needle aspiration and the increased parathyroid hormone concentration in the fluid established the diagnosis. Five patients, in four of whom the cysts reappeared after one (3 cases) or seven (1 case) needle aspirations, underwent surgical resection of the cysts. Six other patients were followed conservatively after the aspiration maneuver. In four patients with enough follow-up time for evaluation, the cyst fluid has not reaccumulated 5, 2 and 2 years after only one aspiration, and 1 year after two aspirations. In one patient, the cyst reappeared 9 months after the initial aspiration. Simple percutaneous aspiration may be curative in some cases of nonfunctioning parathyroid cysts.