Salivary gland choristoma of the middle ear: A case report and review of the literature

A choristoma is a benign mass of mature tissue that develops at a site in which such tissue is not usually found. These lesions are a result of defective embryonic development. Choristomas of the salivary gland rarely occur in the middle ear. In this case report, we present a patient with such a tumor and review pertinent studies in the literature. An analysis of the 31 cases (including our account) published thus far showed that salivary gland choristomas of the middle ear are usually unilateral (96.8%) and most often develop in the posterosuperior tympanum (75%). The reported cases were usually associated with an ossicular deformity or erosion (81.3%) or an abnormal intratympanic facial nerve (61.2%). A conductive hearing loss that developed during the patient's childhood was the most common presenting symptom (93.6%). A mass behind an intact tympanic membrane was visible (61.3%) or was, discovered by computed tomography or during exploratory tympanotomy. A definitive diagnosis of this lesion can be based only on the results of a pathologic examination. Although choristomas are benign, they should be excised if the facial nerve will not be jeopardized. Hearing improvement was reported in 6 of 7 (85.7%) patients who underwent ossicular reconstruction.