Cholesterol granulomas of the middle ear tend to be benign in nature, frequently seen by otologists during cholesteatoma or chronic otitis media surgery and easily dealt with by evacuation. In contrast, cholesterol granulomas of the petrous apex appear to have a more aggressive nature and present significant pathological threats. We present a case of a large destructive cholesterol granuloma of the middle ear eroding the middle and posterior cranial fossa bone and dura to exert a mass effect upon the temporal lobe. We emphasize the destructive potential of this extremely rare middle-ear cholesterol granuloma, and draw attention to the distinction between this variant and the commonplace and benign form of the lesion more usually found at this site. We also present the current theories of the aetiology of cholesterol granuloma formation with possible explanations for the rare aggressive behaviour.