Neurosarcoidosis--the great mimicker

INTRODUCTION: Neurosarcoidosis is rare and difficult to diagnose especially in the absence of systemic involvement. CASE REPORT: A 22-year-old African-American man presented with inability to gaze laterally. He underwent magnetic resonance imaging (MRI) the day before that revealed "a 5-mm enhancing mass with surrounding edema in the pons anterior to the fourth ventricle most likely compatible with pontine glioma." CT angiography of the brain was negative. Two days later, the patient developed right facial droop. During craniotomy, a small lesion of rubbery consistency was identified at the mid-portion of the floor of the fourth ventricle. Frozen-section study came suggestive of lymphoma. Further pathological examination revealed sarcoidosis. The patient was discharged on prednisone, and he recovered quickly and completely. CONCLUSION: Neurosarcoidosis can mimic common neurosurgical entities. It is important to keep neurosarcoidosis in mind when making the diagnosis, which often requires biopsy.