Osteomas and exostoses of the external auditory canal. A clinical, histopathologic and scanning electron microscopic study.

Osteomas of the external auditory canal are considered clinically to be discrete, pedunculated bone lesions arising along the tympanosquamous suture. They are benign lesions but often are slowly progressive in size. Exostoses of the external auditory canal are broad-based elevations of bone usually multiple and bilaterally symmetric, involving the tympanic bone. It appears that both clinical and histopathologic evidence is sufficient to justify the impression that these two lesions should be considered separate entities and clinical diagnostic and histopathologic criteria have been suggested for diagnosis of these lesions.