ACROMEGALY AND HYPERPROLACTINEMIA IN A PATIENT WITH POLYOSTOTIC FIBROUS DYSPLASIA - DYNAMIC ENDOCRINE STUDIES AND TREATMENT WITH THE SOMATOSTATIN ANALOG OCTREOTIDE

Acromegaly and hyperprolactinemia have been described in association w ith polyostotic fibrous dysplasia; the pathogenetic mechanisms involve d in the development of the endocrinopathies is unknown. We report a 2 6-year-old man with polyostotic fibrous dysplasia and hypersecretion o f GH and PRL. Plasma GH, PRL, and insulin-like growth factor-I (IGF-I) were elevated. Glucose-non-suppressible plasma GH concentrations, GH responsiveness to TRH and GHRH, and GH suppression after a test-dose o f somatostatin, octreotide, and bromocriptine were found. Plasma GHRH levels were within the normal range (< 25 ng/l). Computed tomography o f the sella turcica and visual fields were normal. [In-111-DTPA-D-Phe( 1)]-octreotide scintigraphy were used to localize a possible tumor; no radioactivity was visualized at the site of the hypothalamus, the pit uitary or elsewhere in the body but a considerable accumulation of rad ioactivity was found in the os frontalis. Therapy with octreotide by c ontinuos sc infusion partially suppressed GH and IGF-I (and normalized PRL). The results suggest that hypersecretion of GH in our patient is not due to a GH-secreting pituitary tumor, eutopic or ectopic hyperse cretion of GHRH or autonomous somatotroph function. The origin of the disease in this patient might be an abnormal hypothalamic regulation o f somatotrophs and/or an alteration in the transmembrane signalling sy stems.