Ectopic Cavernous Sinus Microprolactinoma Treated Medically

Ectopic prolactin-secreting microadenomas are rare and management is often surgical in contrast to intrasellar pituitary prolactin-secreting microadenomas. We present a case of ectopic dopamine-resistant microprolactinoma treated with cabergoline which led to symptom resolution, hormonal remission, and cystic degeneration of the tumor. A 30-year-old active duty male presented with a chief complaint of inability to maintain an erection for 6 months. Initial workup revealed suppressed serum testosterone of 128.60 ng/ml with an elevated prolactin level at 275.10 ng/ml. Pituitary magnetic resonance imaging showed a small mass measuring 9 mm in the left cavernous sinus. Medical management was initiated with cabergoline, which was titrated over the course of a year from 0.5 mg a week to 3.5 mg a week at its peak before being weaned off completely at 54 months. After treatment, the patient's symptoms resolved, his prolactin decreased to 29.5 ng/ml, near-normal, and his tumor had decreased size with cystic degeneration. Management for any prolactinoma has three primary goals: remittance of symptoms, decrease in prolactin levels, and decrease in tumor size. These are achieved through primarily medical management or surgery. Even though ectopic microprolactinomas are still frequently addressed surgically, this case shows that medical therapy can successfully treat ectopic prolactin-secreting pituitary microadenomas even in cases of dopamine resistance.