Adenoma of the middle ear mucosa.

Benign adenomas of the middle ear are rare tumors. To date, approximately 100 cases of adenomatous neoplasms of the middle ear space have been collected in the United States Armed Forces Institute of Pathology, Washington D.C. This report describes two cases of primary adenomatous neoplasms confined to the middle ear cleft seen at the Department of Otorhinolaryngology at Ludwig Maximilians University Hospital, Munich. Although tumors are derived from lining epithelium of the middle ear mucosa, the unique feature of our first case was based on its origin in the epitympanic part of the tympanic membrane. Histopathology was characterized by an adenomatous morphology without atypia or mitoses, proving its benign behavior. No evidence was found for invasion of adjacent tissue. Simple surgical removal afforded excellent prognosis. Clinical behavior, histological appearance, origin of tumors and differential diagnosis are discussed.