title: Pituitary cyst presenting with hyponatremia and increased secretion of brain natriuretic peptide. Case report.
abstract: In most cases of pituitary cyst there are no clinical symptoms and the lesions are found incidentally. The authors report the case of a 60-year-old man with a pituitary cyst causing visual disturbance and hyponatremia. The patient presented with appetite loss and general fatigue. On admission, blood workup showed severe hyponatremia (112 mEq/L), and bitemporal hemianopsia was observed on neurological examination. Magnetic resonance imaging revealed an intra- and suprasellar region cystic mass extending to the frontal base and hypothalamic area. The serum level of brain natriuretic peptide (BNP) was elevated (92 pg/ml) with polyuria and excessive Na excretion. Transsphenoidal surgery was performed to drain the cyst. The cyst wall was partially excised and the cystic fluid was aspirated. The secretion of BNP normalized postoperatively, and the hyponatremia and visual symptoms resolved. Histological examination, including an electron microscopy study, confirmed the diagnosis of a simple cyst. This appears to be the first reported case of a pituitary simple cyst associated with hyponatremia and an elevated BNP level.
authors.affiliation: Department of Neurosurgery, Teikyo University School of Medicine, Tokyo, Japan.
authors.forename: Jae-Hyun
authors.initials: JH
authors.lastname: Son
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Fujimaki
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Tsuchiya
authors.forename: Teruyuki
authors.initials: T
authors.lastname: Ishii
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Takagi
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Nakagomi
mesh_terms: D003560:Cysts / Q000150:complications* / Q000175:diagnosis / Q000378:metabolism* / Q000601:surgery; D006423:Hemianopsia / Q000209:etiology; D006801:Humans; D007010:Hyponatremia / Q000209:etiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D009318:Natriuresis; D020097:Natriuretic Peptide, Brain / Q000378:metabolism*; D010900:Pituitary Diseases / Q000150:complications* / Q000175:diagnosis / Q000378:metabolism* / Q000601:surgery; D011141:Polyuria / Q000209:etiology; D013396:Suction
chemical_list: D020097:Natriuretic Peptide, Brain