Chapter 635 Tumors of the Ear and Temporal Bone
Benign tumors of the external canal include osteomas and monostotic and polyostotic fibrous dysplasia. Osteomas manifest as bony masses in the canal and require removal only if hearing is impaired or external otitis results; osteomas may be confused clinically with exostoses (Chapter 495.2). Masses occurring over the mastoid bone, such as first branchial cysts, dermoid cysts, and lipomas, may be confused with primary mastoid tumors; imaging can help with the diagnosis and treatment plan.
Eosinophilic granuloma, which can occur in isolation or as part of the systemic Langerhans cell histiocytosis (Chapter 501