Dramatic and rapid shrinkage of a massive invasive prolactinoma with bromocriptine: a case report.

Shrinkage of a massive, highly invasive, longstanding (probably 40 years) prolactin-secreting pituitary tumour is described in which tumour volume was reduced by 40% 8 d after beginning bromocriptine treatment. After 4 months of treatment the tumour was only 11% of the pretreatment volume and by 8 months it was further reduced in size being confined to the pituitary fossa, which was partially empty. Reduction in tumour volume was accompanied by a gradual reduction in serum prolactin concentrations to normal values at 4 months. Between 4 and 18 months serum prolactin has remained normal on 5 mg of bromocriptine daily. Visual function improved within 48 h of starting bromocriptine and was almost normal by 6 d. CSF rhinorrhoea developed as the tumour shrank and was successfully managed with the relatively minor procedure of a diversionary lumbo-peritoneal shunt. Bromocriptine should be considered as the initial treatment of choice for massive invasive prolactinomas because of the significant risk of morbidity from neurosurgical treatment.