Familial pheochromocytomas with unusual associations.

Pheochromocytoma occurs in a familial pattern in approximately 10% of patients. Although most familial pheochromocytomas are an expression of the genetic abnormality of neuroectodermal dysplasia or the genetic syndrome of multiple endocrine neoplasia, some familial pheochromocytomas occur without associated disease. Two patients with familial pheochromocytoma are described. One had an extraadrenal tumor, producing severe renal artery stenosis and in whose family pheochromocytomas were found in three successive generations. A second had multiple pheochromocytomas associated with von Hippel-Lindau disease and a family member with multiple endocrine neoplasia type 2. The combinations and permutations of these genetic entities form discrete syndromes, with other peculiar interrelationships, pathologically related to an aberration in the migration, growth, and differentiation of the neural crest cells, and emphasizing their common neuroectodermal origin. The unique features that characterize the familial pheochromocytomas and cause diagnostic and therapeutic challenges are reviewed.