Removal of Hairy Polyp of the Eustachian Tube Using a Novel Skull Base Approach: Extended Transmastoid Excision

Abstract

Hairy polyps are rare dermoid tumors associated with the temporal bone. The majority of reported cases have been left-sided, in women, and with significant middle ear or nasopharyngeal components, allowing removal by a simple transmastoid or endoscopic approach. We present the case of a 3-year-old girl with a hairy polyp of the left eustachian tube. Diagnosis was made at surgery 14 months after initial presentation. Preoperative CT and MRI aided surgical planning but were nondiagnostic. The location of this lesion high in the eustachian tube and its intimate association with the carotid artery precluded a traditional transcanal, endoscopic, or simple transmastoid approach and required more aggressive surgical dissection. A novel extended transmastoid skull base approach with removal and replacement of the anterior external canal wall and glenoid fossa provided complete visualization of the intrapetrous portion of the carotid artery, which was immediately adjacent and adherent to the tumor, and granted access to the apex of the cartilaginous eustachian tube from which the tumor arose. This exposure allowed for complete excision of the tumor and reconstruction of the ear with the usual features of a canal wall down mastoidectomy. This case represents the 15th such lesion reported in the English literature and the first described extended transmastoid skull base approach for complete visualization of the intrapetrous portion of the carotid artery and access to the cartilaginous eustachian tube.