Hypothalamic hamartoma: a report of 2 cases.

Two patients with hypothalamic hamartoma presented with isosexual precocious puberty. LHRH challenge showed a pubertal LH response in both cases. Serum FSH responses to LHRH were pubertal in case 1, but prepubertal for case 2. Computed tomography revealed isodense noncontrast-enhancing retrosellar mass lesions in both cases. The tumors were composed of mature neurons and neuroglial tissue. Electron microscopy of the lesions failed to demonstrate dense core (neurosecretory) granules in either case. Subtotal removal of the harmartomas resulted in decreased LH responsiveness to LHRH in both cases. Serum FSH responsiveness to LHRH was not significantly suppressed postoperatively in case 1, and FSH responsiveness to LHRH in case 2 showed exaggerated levels, more typical of very young prepubertal girls. Postoperative magnetic resonance imaging (MRI) scans of both patients are also presented.