Transcanal endoscopic resection for leiomyoma of the external auditory canal and a review of the literature.

Leiomyoma usually originates from the uterus and alimentary tract, but in extremely rare cases leiomyoma can appear in the external auditory canal. Here we present a 37-year-old man with right auricular fullness. Preoperative findings suggested benign tumor or cholesteatoma in the right external auditory canal. We performed total resection using an endoauricular approach with transcanal endoscopic ear surgery. Histopathological and immunohistochemistry examination confirmed the diagnosis of leiomyoma of external auditory canal. Leiomyoma arising from soft tissue, including that in the external auditory canal, is classified into two types: that from the arrectores pilorum muscles and that from the muscle coats of blood vessels. Only four cases of leiomyoma of external auditor canal have been published in the English literature. The other four cases demonstrated vascular leiomyomas. This is the first report of leiomyoma of the EAC arising from arrectores pilorum muscles.