Parathyroid adenolipoma: clinical and morphologic features.

Adenolipoma--or parathyroid hamartoma--has been described s a very rare lesion of the parathyroid gland, often unassociated with clinical hyperparathyroidism. A few reported cases in which the diagnosis was discovered pathologically following parathyroid resection for hyperparathyroidism have been called unique. In a 2-year period the diagnosis of parathyroid adenolipoma was made in three instances, with each clinical presentation consistent with primary hyperparathyroidism. In the first patient, a 64-year old man reporting to an emergency department for treatment of migraine headache, a prolonged history of unrecognized hypercalcemia was discovered, and he underwent cervical exploration. At operation, a 105 by 2.0 cm tumor weighing 17.5 gm was encountered. The other two patients were middle-aged women who had hypercalcemia (one requiring preoperative calcitonin treatment). The diagnosis of adenolipoma was made morphologically, although the clinical course was otherwise indistinguishable from other forms of primary hyperparathyroidism. Each of the three patients were cured following adenolipoma resection. This small series of patients in the experience of a single surgeon in a brief period might indicate that this diagnosis is by no means rare, and the functional nature of these tumors was the characteristic that brought them to diagnosis. The hypercalcemia was somewhat more severe in these cases--but the hyperparathyroidism was otherwise unremarkable. The morphologic features of these tumors include unusual size, proliferating fat content, and a fibrillar stroma. Adenolipoma of the parathyroid can cause primary hyperparathyroidism and should be considered in the differential diagnosis of the morphologic lesions of the parathyroid glands that can produce a hypercalcemic syndrome.