Aggressive papillary middle-ear tumor. A clinicopathologic entity distinct from middle-ear adenoma

A 29-year-old woman had a middle-ear mass that resulted in hearing loss and seventh-nerve palsy. The tumor invaded the petrous bone, the mastoid, at least one semicircular canal, and then extended into the posterior fossa. Microscopically, it consisted of complex, interdigitating papillae lined by uniform, cuboidal to low columnar cells. The cells resembled the epithelium of the normal middle ear and middle-ear adenoma, but the papillary architecture distinguished this neoplasm from the latter, nonpapillary tumors. Papillary middle-ear tumors are locally invasive. We propose the term "aggressive papillary middle-ear tumor" (APMET). Nine other examples of APMET have been reported under various diagnostic terms. All have been locally destructive with frequent intracranial invasion. Although none of the tumors has metastasized, one patient died of uncontrolled local disease. For this reason, APMET must be distinguished from nonpapillary middle-ear tumors.