Bromocriptine-induced Brainstem Angulation in a Patient With Invasive Prolactinoma

Abstract

A 29-year-old male patient presented with a 2-year historyof severe frontalheadache,nasalobstruction,and visual defects in April 2004, along with increased prolactin level (16 808 ng/ml) and decreased cortisol level (8.3 g/L). Brain magnetic resonance imaging (MRI) (Figure 1, A–C) showed that a giant invasive prolactinoma and odontoid processexceededchamberlain lineover1.3cmandthebrainstem at an angle of 36.5° (Figure 1B). A computed tomography scan (Figure 2, A–D) showed that the clivus and occipitalwereseriouslydestroyed.Thepatientwas treatedwith bromocriptine (BRC), which was gradually increased to 15 mg/d, and no side effect was observed. The serum prolactin level also returned to normal in November 2006. Ten months after BRC treatment, MRI (Figure 1, D–F) revealed that the size of the prolactinoma was significantly reduced and that the bone of total clivus had disappeared and the brainstem crawled over the bulgy odontoid process (the angle of brainstem was 61.1°; Figure 1E). Similar magnetic resonance images were found in January 2012 (Figure 1, G–I). Some complications associated with dopamine agonist treatment for prolactinomas, such as cerebrospinal rhinorrhea(1),emptysella turcica (2),andopticchiasmaherniation (3), have been reported. To the best of our knowledge, we first report here that a male patient with invasive prolactinoma developed the brainstem angulation, which crawls over the bulgy odontoid process, after BRC treatment. Studies show that occipito-cervical fusion is necessary for the cranio-cervical joint instability due to skull base bone destruction (4,5).However, theworseangulationofbrainstem and symptoms were not observed after BRC and cortisol replacement therapy in the follow-up period without the occipito-cervical fusion.