A case of gonadotropin-producing pituitary adenoma mimicking a tuberculum sellae meningioma

Abstract

We report a case of gonadotropin-producing pituitary adenoma mimicking a tuberculum sellae meningioma. A 59-year-old man was admitted to our department. For 4 years he had complained of recent memory disturbance and hyposmia. Ophthalmological examination revealed a slight superior visual field defect. The remainder of the neurological examination was normal. MR imaging demonstrated a 5 x 3 x 3 cm sellar/suprasellar tumor extending into the frontal skull base as an iso-intense mass with homogeneous enhancement an T1-weighted images. Endocrinological evaluation revealed a high FSH (111.06 mIU/ml) but a normal LH level in serum. The presumptive diagnosis was tuberculum sellae meningioma or invasive pituitary adenoma. A bifrontal craniotomy was performed, disclosing a smooth reddish brown mass that was easily dissected from adjacent brain including the pituitary gland. The tumor was totally removed without complications. Histopathological examination revealed a gonadotropin-producing pituitary adenoma. Serum FSH level fell to within normal range.