Bromocriptine therapy as pre-operative adjunct of non-functional pituitary macroadenomas

Although bromocriptine administration produces reduction in size of prolactinomas, its effect upon non-functional pituitary adenomas is still uncertain. Nine patients with macroadenomas, 2 of them with prolactinomas and 7 with non-functional tumours, received bromocriptine prior to transsphenoidal surgery. Size reduction of tumour mass was assessed by computerized tomography and by visual field examination before and following bromocriptine treatment. There were no signs of size diminution or pathological changes in the non-functional adenomas treated pharmacologically during 15 to 360 days. Both patients with prolactinomas had radiological evidence of size reduction and morphological changes on microscopic examination. These 2 patients had tumours with prolactin granules (immunocytochemistry) and adenoma cells showed reduced cytoplasmatic, nuclear and nucleolar areas. Neither vascular damage, cell necrosis, nor infarction was observed by electron microscopy. Patients with non-functional tumours as determined by immunocytochemistry and hormone production did not benefit from bromocriptine. The suggestion that bromocriptine can be used as primary treatment for non-functional pituitary tumours is not supported by the present study. Conversely, in cases of macroprolactinoma, bromocriptine is a useful pre-operative adjunct when surgery is planned and for those patients in whom a surgical cure is considered difficult owing to the tumour size.