Cholesterol Granuloma of the Petrous Apex - MedPix™: 1338

Please Choose an Item from the List

(Click each item)

History:

A 13-year-old african-american girl presented with a 2-month history of intermittent right-sided headaches and diplopia. She described mild dysequilibrium but no hearing loss and had no

Exam:

Physical examination demonstrated right-sided sixth nerve palsy. The remainder of the exam was within normal limits.

Image Findings:

Differential Diagnosis:

Actual Diagnosis:

Cholesterol granuloma of the right petrous apex.

How Was Dx Confirmed:

Treatment and Outcome:

Patient Discussion:

Because the lesion abutted the posterior wall of the sphenoid sinus, it was possible to perform an image-guided endoscopic procedure through the paranasal sinuses to drain it.

The traditional approach to this lesion has been through craniotomy or by an approach though the mastoid process. Approaching the lesion through the paranasal sinuses is less invasive and has the added benefit of facilitating followup; the cyst cavity can be inspected endoscopically.

Cholesterol granuloma of the petrous apex is an unusual lesion believed to result from chronic obstruction of the air cells of the petrous apex and subsequent inflammation (1,2). Obstruction of the air cells, which normally communicate with the middle ear, is usually the result of chronic disease such as chronic otitis media. The inflammatory process is believed to involve recurrent bleeding into the obstructed air cells. Products of blood degradation, including cholesterol crystals, form a slowly expansile, fluid-filled lesion.

Presenting signs and symptoms of this disease relate to the anatomic position of the granuloma. Petrous apex granulomas usually present with cranial nerve compression; cranial nerves V though VIII may be involved (4). Headache, diplopia, hearing loss, vertigo and facial nerve weakness or spasm may be present.

The characteristic appearance of a cholesterol granuloma of the petrous apex on CT is as an expansile soft-tissue mass in the petrous apex. On MR, the lesion does not enhance and has high signal on both T1WI and T2WI. The high TIWI signal is believed to be the result of blood products, and helps to differentiate the lesion from a cholesteatoma or a neoplasm.

Surgical treatment of the cholesterol granuloma is achieved by drainage. Re-establishment of air exchange prevents recurrence of the lesion (4).

http://radiology.rsnajnls.org/cgi/content/abstract/153/3/705

http://www.emedicine.com/ent/topic244.htm
( ... Topic continues ... )

** Click Here -

- for the Complete Topic **

Press the [SPACE-BAR] to see the Next Image

[<-] CURSOR KEYS [->]
Will scroll through all images.

To Earn CME Credits, you must first Sign In.

Browser Warning - If asked, Please accept our Security Certificate

Can I use it? -

Options shown in Gray become available with the Case Answer

Click on the image to Read the Caption.
Captions are hidden during the Quiz - but the Teaching Points and Hints are visible.

To read a description of the image,
Click [Caption Peek] or [Show Answer]
below the image.
NOTE: This may reveal the answer to the case.

- Compact TF Case Display
Click Here to Share this Case or Image by Email -