Cholesterol Granulomas of the Petrous Apex
The petrous apex is a pyramid shaped portion of the temporal bone that is interposed between the sphenoid and occipital bones of the skull base. It is located approximately three to four centimeters deep to the middle ear.
Cholesterol granulomas are rare, benign (non-cancerous) cysts produced either in response to air cells of the petrous apex being blocked or because spontaneous bleeding from adjacent marrow spaces incites inflammation. In either case, breakdown products of blood (including cholesterol) accumulate in the air cells, the immune system treats this cholesterol debris as foreign, and an enlarging granuloma results.
Cholesterol granulomas of the petrous apex are expansile and can be dangerous due to their proximity to the middle ear, facial nerve, vestibulocochlear nerve (the nerve that sends hearing and balance information from the inner ear to the brain), the trigeminal nerve, the petrous carotid artery, the inner ear, and intracranial contents. Early symptoms include hearing loss, tinnitus, dizziness, facial weakness, sensory abnormalities of the face and vague headaches that seem worst immediately behind the eyes. If left untreated, more serious patient compromise may result from permanent cranial nerve or inner ear damage as well as from destruction of the temporal bone.
Diagnostic workup for petrous apex lesions includes a comprehensive audiogram (hearing test) and temporal bone imaging – using both CT and MRI technologies. Once a cholesterol granuloma is discovered, it may be observed if small and asymptomatic. Should surgery be required, several approaches to the petrous apex may be used including the hypotympanic/infracochlear approach, the transotic approach and the middle fossa approach. Occasionally, the hypotympanic/ infracochlear approach can be performed endoscopically, minimizing use of external incisions. Some petrous apex granulomas can even be reached through the nose; if such were the case, appropriate referral to a skull base rhinologist would be provided. Each patient case is different, depending on the location of the cholesterol granulomas and the severity of symptoms experienced.
Why Choose Us
- Dr. Abraham Jacob, Medical Director for Ear & Hearing (E&H) at the Center for Neurosciences (CNS), is fellowship trained in Otology, Neurotology, and Cranial Base Surgery. He is the first and most experienced Neurotologist in Tucson. As such, he is uniquely qualified to perform transtemporal (hypotympanic/infracochlear and transotic) and middle cranial fossa approaches to the petrous apex.
- Dr. Jacob was a founding member of the University of Arizona (UA) Department of Otolaryngology prior to his departure and transition to CNS. At UA, he was Vice Chair of ENT and held the rank of full Professor with Tenure. He has an international reputation as an expert for treating ear diseases.
- Dr. Jacob transitioned his practice to the Center for Neurosciences in early 2017 as he felt that the new environment helped him to optimize delivery of personalized ear and lateral skull base care for his patients.