Familial hypopituitarism with large sella turcica.

We studied endocrine function in three siblings with short stature and enlargement of the sella turcica. Sellar volumes were 5.9, 3.7 and 4.0 standard deviations above age-specific means. Computed tomography or pneumoencephalography showed full sellae without suprasellar extension. Basal thyrotropin levels were low despite hypothyroidism and increments were less than 3 micromicron per milliliter after thyrotropin-releasing hormone injection. Stimulated growth hormone levels were less than 5 ng per milliliter, declining to less than 2 ng per milliliter after thyroxine treatment. Both thyroxine and growth hormone treatments were required for rapid growth. Impaired thyrotropin responses to thyrotropin-releasing hormone distinguish these patients from most cases of idiopathic or familial deficiency of thyrotropin and growth hormone. Persistent deficiency of growth hormone during thyroxine treatment indicates that the defects is not limited to thyrotropin structure or release. The findings are compatible with either familial neoplasia of the anterior pituitary or a regulatory defect promoting anterior pituitary-cell hyperplasia and inhibiting thyrotropin and growth hormone release.