Rapid resolution of visual field defects and reduction in macroprolactinoma size with bromocriptine therapy. A case report.

Therapy for large prolactinomas depends very much on the treatment modalities available at a particular institution. Surgery is often unsuccessful in restoring endocrine function to normal. Previous reports have demonstrated evidence of tumour regression after 3 or more months' therapy with bromocriptine (Parlodel; Sandoz). More recently, objective evidence of rapid reduction in the size of large prolactin-secreting pituitary tumours, in patients who have had no prior therapy, has been reported. We describe a patient presenting with a chiasmal syndrome and amenorrhoea due to a pituitary macro-adenoma with suprasellar extension i whom rapid tumour regrowth to its pre-operative size occurred 3 months after surgery and irradiation. Administration of bromocriptine (up to 7.5 mg/d) resulted in complete resolution of the visual field defects, radiographic evidence of tumour regression and normoprolactinaemia within 12 days of commencing bromocriptine. Further significant tumour size reduction and improved anterior pituitary function were found after another 5 weeks of therapy.