Agenesis of the cervical portion of the internal carotid artery (ICA) may result in blood supply to the ipsilateral cerebral hemisphere being provided by an enlarged inferior tympanic branch of the ascending pharyngeal artery. This enlarged vessel, passing through Jacobson's canal and anastomosing with the likewise enlarged caroticotympanic branch of the ICA in front of the promontorium, may simulate a middle ear mass. We present five patients with this unusual anatomical variant, three of which underwent biopsy of what was believed to be a middle ear tumour. One patient experienced rupture of an arterial aneurysm in the middle ear successfully treated with endovascular application of detachable platinum coils. It is mandatory for ENT-surgeons and radiologists who perform head-and-neck examinations to recognize this anatomical variant, not mistaking it for a tumour, since biopsy of a large artery supplying the brain may have disastrous consequences. In patients with otorrhagia, an arterial aneurysm must be considered as a possible source of bleeding, in some cases amenable for treatment with an endovascular technique. The diagnosis of “aberrant internal carotid artery” is usually made with CT of the temporal bone or MR of the skull base. Cerebral angiography is in most cases not necessary, unless an endovascular procedure is planned.
Pseudoaneurysm of the Petrosal Internal Carotid Artery in the Middle Ear as a Complication of Middle Ear Cholesteatoma
