Learning Objectives: Otologists should be aware of vascular malformations of the temporal bone. Aberrant ICA in the middle ear is a very rare finding and its damage during surgical procedures can lead to severe complications. When there is a suspicion of a middle ear vascular anomaly, CT scan of the temporal bone is the standard. It should be performed before any middle ear surgery, to avoid complications related to misdiagnosis. Endoscopic examination improves diagnosis of middle ear pathology.

Introduction: Aberrant internal carotid artery (ICA) in the middle ear is a rare vascular anomaly of the temporal bone and its diagnosis can be difficult because the symptoms and signs are often nonspecific.

Accidental injury during myringotomy or other middle ear surgeries, can lead to severe complications.

Methods: We report a case of a 47-year-old woman who complained of fullness in the right ear for 6 months, without hearing loss or tinnitus. She had no previous otological pathology.

Endoscopic otoscopy revealed a slight white-rosy mass behind the inferior half of the tympanic membrane.

A CT scan of the temporal bone confirmed aberrant ICA passing through the middle ear. A magnetic resonance angiography was also performed.

The patient was informed about the diagnosis and the possible complications of middle ear interventions, and regular follow-up was arranged.

Results: Color changes on otoscopic examination may suggest the presence of a vascular anomaly, as sometimes seen in aberrant ICA, due to its intratympanic course.

These features were seen in the CT scan: the ICA ran more laterally, there was an enhanced mass in the hypotympanum and a deficient bony plate along the tympanic portion of the ICA, bulging into the tympanic cavity.

The magnetic resonance angiography showed a lateralized right ICA with a reduced diameter.

Conclusions: Aberrant ICA in the middle ear should be identified before middle ear surgery, because misdiagnosis could lead to surgical complications: hemorrhage, stroke or death may occur if the vessel is damaged.

Clinical diagnosis is difficult because the symptoms and signs are nonspecific or absent and in some cases it can be discovered during middle ear surgery. However, symptoms such as pulsatile tinnitus or conductive hearing loss may be present.

Most authors recommend a conservative approach. If an asymptomatic aberrant ICA in the middle ear is diagnosed any physician involved in the patient's care should be informed.