Aberrant internal carotid artery (ICA) is a rare but a very important vascular anomaly of temporal bone. Misdiagnosis of the anomaly may lead to massive hemorrhage and severe complications during otologic procedures. It is essential to keep this anomaly in mind for any otologic surgeon to prevent catastrophic complications. We present a case of aberrant ICA appeared as a nonpulsatile middle ear mass. The patient had a complaint of hearing loss, and the otoscopic examination of the patient revealed a tympanic membrane perforation and a blue-reddish retrotympanic mass. Multidetector computed tomography (MDCT) is a useful tool that may provide excellent visualization of temporal bone for the diagnosis of aberrant ICA. Otolaryngologists should be aware of the possibility of a vascular anomaly of temporal bone when a patient presents with a blue-reddish mass in the middle ear. 1. Introduction An aberrant internal carotid artery (ICA) in the middle ear is a rare but an important vascular anomaly of the temporal bone that every otolaryngologist and radiologist should know about [1]. It is generally accepted to be a collateral pathway that occurs as a result of agenesis of the first embryonic segment of the ICA [2]. The clinical symptoms and signs of aberrant ICA are often nonspecific and include hearing loss, pulsatile tinnitus, and a retrotympanic mass behind the anteroinferior part of the membrane [3, 4]. It can mimic glomus tumors and other vascular temporal bone lesions (dehiscent jugular bulb, cholesterol granuloma and petrous carotid aneurysms, and pseudoaneurysms and hemangiomas) [5, 6]. A misdiagnosis of this anomaly may subject patients to aural bleeding during myringotomy or tympanotomy and serious consequences which is potentially life threatening. We report a case to describe and highlight the clinical and radiological features of the aberrant internal carotid artery and to discuss strategies for diagnosis and management. 2. Case Report A 47-year-old female patient presented to our clinic with a five-year history of hearing loss in the left ear. Her otoscopic examination revealed a central tympanic membrane perforation and a nonpulsatile blue-reddish mass protruding from the middle ear cavity. She did not have a history of discharge or bleeding from her left ear (Figure 1). Pure tone audiogram showed 38？dB conductive hearing loss of the left ear. Figure 1: Nonpulsatile blue-reddish mass behind the perforated tympanic membrane. Computerized tomography scanning of the temporal bone was performed, and a left-sided aberrant ICA with bony dehiscence of
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