Sebaceoma of the external auditory canal

Abstract

Sebaceomas of the external auditory canal (EAC) are extremely rare. The recognition of sebaceoma is important as this benign tumor can be be part of the spectrum of the Muir-Torre syndrome (MTS), which is associated with visceral malignancy and multiple adenomatous polyps. Proper histological identification is thus important for further investigation. We describe a rare case of a sebaceoma that was confined to the EAC. Subsequent immunohistochemical (IHC) staining analysis of the mismatch repair genes (MLH1, MSH2, MSH6, and PMS2) was needed to investigate MTS. Even though the patient has had the history of colon cancer, the result was negative. Otorhinolaryngologists should be aware of rare sebaceoma and its potential association with the internal malignancy, besides the limitation of IHC screening test.