title: Size reduction of an ACTH-secreting pituitary macroadenoma in Nelson's syndrome by sodium valproate: effect of withdrawal and re-institution of treatment.
abstract: We describe herein the reduction in the size of an ACTH-secreting pituitary macroadenoma in a patient with Nelson's syndrome during chronic administration of sodium valproate, and the changes in tumour volume after withdrawal and re-institution of treatment. The patient had elevated plasma ACTH levels (1123-1255 pmol/l), which increased markedly after CRH stimulation. A first 4-month course of sodium valproate administration (600 mg/day, orally) was started. Plasma ACTH fell to 550-726 pmol/l with persistence of responsiveness to CRH; brain computed tomography showed a clearcut reduction of tumour size. One month after drug withdrawal, the tumour volume appeared unchanged and plasma ACTH values ranged between 374 and 440 pmol/l. One and a half year after drug withdrawal, a brain computed tomography showed re-expansion of the pituitary adenoma with evidence of suprasellar extension, which had never been seen previously. Plasma ACTH ranged between 113 and 199 pmol/l. A second course of sodium valproate was started; after three months, a brain computed tomography documented clearcut reduction of tumour volume from a suprasellar extension to a partially empty pituitary fossa. Plasma ACTH ranged from 396 to 542 pmol/l with persistence of responsiveness to CRH. The present report documents for the first time the reduction of tumour size in a patient with an ACTH-secreting macroadenoma by chronic administration of sodium valproate.
authors.affiliation: Divisione di Endocrinologia, Ospedale Niguarda Cà Granda, Milano, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Loli
authors.forename: M E
authors.initials: ME
authors.lastname: Berselli
authors.forename: F
authors.initials: F
authors.lastname: Vignati
authors.forename: C
authors.initials: C
authors.lastname: De Grandi
authors.forename: M
authors.initials: M
authors.lastname: Tagliaferri
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D001921:Brain / Q000000981:diagnostic imaging; D006801:Humans; D008875:Middle Aged; D009347:Nelson Syndrome / Q000188:drug therapy*; D010911:Pituitary Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000378:metabolism*; D014057:Tomography, X-Ray Computed; D014635:Valproic Acid / Q000627:therapeutic use*
chemical_list: D014635:Valproic Acid; D000324:Adrenocorticotropic Hormone