Morphological changes in bromocriptine-treated pituitary tumours.

Eight cases of pituitary tumours (3 prolactinomas, 3 tumours secreting GH and 2 tumours with a concomitant secretion of GH and PRL) were treated prior to open surgery with bromocriptine. These cases emanated from a series of totally 128 operated cases with pituitary tumours. The tumour tissue was analysed by light and electron microscopy. In 4 cases severe morphological changes had occurred; minor changes were found in 4 cases. Specific morphological changes indicating a dysfunction effect had occurred in one case. It has not been possible to document any consistent finding with regard to tumour susceptibility to bromocriptine. In the present limited material, the extent of morphological damage could not be correlated to dose, duration of treatment period, or endocrinological type of tumour. Our 8 patients with tumours treated with bromocriptine prior to surgery were cases demonstrating no or unsatisfactory clinical/radiological effects of drug therapy.