Endocrine Abstracts

Introduction: Cystic prolactinomas are considered resistant to volume depletion by dopamine agonists (DAs). Because of the effectiveness and tolerability, dopamine agonists (DAs) are the first line therapies in prolactinoma and reduce tumor mass as well as prolactin levels in most of all patients. Rathke’s cleft cysts, craniopharyngiomas and arachnoid cysts are differential diagnoses to keep in mind. DAs resistance or intolerance, psychiatric disorders associated with dopamine agonist use and patient preference can be indications for surgical intervention. Large, predominantly cystic prolactinomas are usually treated surgically and are presumed to be resistant to volume reduction by DAs. Although optimal management of cystic prolactinomas are not defined yet, several individual case reports and case series have suggested that DAs may reduce these lesions. Here we present a patient with cystic prolactinoma responsed to medical treatment.

Case report: A 20-year-old women presented with secondary amenorrhea and spontaneous galactorrhea for three months. She has not taken any prolactin-increasing medications and was not pregnant. Her biochemical, hematological laboratory tests and hypophysis function tests were normal except prolactin. Her prolactin level was 133 ng/ml (normal value is 2.7–19.6) and macroprolactin was negative. Pituitary MR scan revealed a 9×7 mm cystic adenoma at the left side of adenohypophysis. Infundibulum, suprasellar cistern and optic chiasm were intact. Hence her clinical picture was consistent with prolactinoma, we administered cabergolin 0.25 mg twice a week. After three months of cabergolin therapy her prolactin level decreased to 6.5 ng/ml. She had regular menses and no galactorrhea. After eight months, hypopsis mr scan demonstrated a remarkable reduction in the tumor size, measured as 6×3.5 mm.

Discussion: In conclusion, it is appropriate to consider dopamine agonist therapy in patients with cystic prolactinomas before considering surgery.