IMAGING DESTRUCTIVE LESIONS OF THE PETROUS APEX

Cholesterol granuloma and cholesteatoma are the two most common destru ctive lesions of the petrous apex, Arachnoid cyst is less common, Thes e three expansile lesions are often indistinguishable on clinical grou nds, Cholesterol granulomas can be treated effectively through interna l drainage into the mastoid cavity or middle ear, Cholesteatomas, howe ver, are managed by more aggressive and complicated removal, which oft en mandates the sacrifice of hearing, Symptomatic arachnoid cysts are amenable to simple surgical drainage, Therefore, accurate preoperative recognition on computed tomography (CT) and magnetic resonance imagin g (MRI) is important in planning proper treatment, Thirteen cases of d estructive lesions of the petrous apex are analyzed, The authors' expe rience illustrates that the ''typical'' CT and MRI radiographic featur es are diagnostic in some cases, but not in all, In this study the pat hologic findings have been correlated with the radiologic features on both MRI and CT.