[Suprasellar ectopic pituitary adenoma: report of a case]

An extremely rare case of an ectopic pituitary adenoma in the suprasellar region is reported. A 57-year-old man was referred to us in March, 1993, because of bitemporal hemianopsia. Magnetic resonance imaging (MRI) and computed tomography (CT) revealed a well-circumscribed enhancing mass in the suprasellar region. Sagittal tomography of the skull showed normal-sized sella turcica. Endocrinological tests were almost within normal range. The tumor was totally removed by combined right subfrontal and interhemispheric approach. At the time of the operation, we confirmed that the tumor did not continue to the pituitary gland and that the diaphragma sellae was intact. Histological diagnosis of the tumor specimen was pituitary adenoma. Post-operative MRI showed a normal pituitary gland, thus supporting the diagnosis of ectopic pituitary adenoma. To our knowledge, only ten cases of suprasellar ectopic pituitary adenoma have been reported, including our case. Pathogenesis of ectopic pituitary adenoma was briefly discussed.