Adenomatous tumors of the middle ear.

Primary adenomatous tumors of the middle ear are preponderantly benign, resectable lesions and arise from the mucosa (adenomas) or salivary tissue (choristomas). Malignant variants are ill defined, are not characterized histologically, and represent less than 10% of the adenomatous tumors. Their presence may be signaled clinically by facial nerve paralysis, invasion of bone, and chronic otorrhea.