Coexistence of growth hormone-secreting pituitary adenoma and intracranial meningioma: a case report and review of the literature.

The simultaneous occurrence of a pituitary adenoma and an intracranial meningioma is a rare event. We report the coexistence of an eosinophilic pituitary adenoma and a endotheliomatous meningioma, in the sellar region, and evaluate their endocrine, neuro-radiological and immunohistochemical pattern. A 47-year-old woman affected by acromegaly was referred to us. Serum GH level was 82 ng/ml and remained unresponsive to both OGTT (75 g per os) and iv. GHRH 1-29 (100 micrograms); IGF-1 was 807 ng/ml. Eight hours after acute sc administration of octreotide (100 micrograms) GH returned to normal levels (2.3 ng/ml). CT scan showed a large intra- and suprasellar mass involving the right cavernous sinus, with a retrosellar extension along the tentorium. A slight and inhomogeneous enhancement, with a periferal rim of bright signal was apparent at MRI. Conversely, the retrosellar component showed a bright homogeneous enhancement. The patient, therefore, underwent neurosurgery. Histological examination revealed the coexistence of 2 types of tissue: areas of endotheliomatous meningioma were interspersed among sheets of acidophilic adenoma tissue. Immunohistochemical analysis was performed in order to determine the relationship between the two masses: a positive staining for GH was shown in the areas of adenoma, as against for GHRH, neither in the adenomatous tissue nor in the slices of meningioma. Although MRI showed a latero-sellar post-surgical residual of meningioma, serum GH value was < 1 ng/ml. In conclusion, the relationship between the GH-secreting adenoma and the meningioma is unclear; however the GH-hypersecretion is not induced by a hypothetic GHRH-activity from the meningioma.