A blue middle ear mass: Cholesterol granuloma mimicking a glomus tumor and endolymphatic sac tumor.

Cholesterol granuloma (CG) is the most common benign lesion of the petrous apex, however, it can grow significantly large and become destructive causing a diagnostic dilemma. This case presents a 25-year-old female with 2-year history of left-sided progressive and profound hearing loss, a transient left-sided facial paralysis and cranial nerve 10 palsy who presented with a blue middle ear mass. Her diagnosis did not become apparent until direct visualization intraoperatively. The objective of this case study is to highlight the destructive capabilities of CG and the importance to keep it in the differential diagnosis of a large, erosive, expansile skull base lesion in order to avoid overly aggressive resection or other unnecessary treatment.