Cholesterol Cysts of the Temporal Bone: Diagnosis and Treatment

Abstract

Cholesterol cyst (or granuloma) of the temporal bone, a recognized clinical entity distinct from cholesteatoma, is more common than previously thought. Apparently it is caused by obstruction of previously pneumatized temporal bone air cells. Surgical cure is achieved by drainage and reestablishment of normal pneumatization. This paper reviews 14 cholesterol cysts of the temporal bone, emphasizing the importance of preoperative imaging and surgical approach. Use of magnetic resonance imaging differentiates cholesterol cysts from cholesteatoma or other neoplasms. Computed tomography delineates the location of the lesion and defines temporal bone anatomy essential to surgical approach. The two studies together allow the surgeon to properly plan drainage, as in the case of a cholesterol cyst, versus excision or exteriorization, as in the case of cholesteatoma. The infralabyrinthine approach to a petrous apex cholesterol cyst is the procedure of choice when hearing preservation is desired.

Endoscopic trans-sphenoidal removal of cholesterol granuloma of the petrous apex: case report and literature review

“…16,17 Petrous apex cholesterol granulomas tend to remain clinically silent, but as the lesion expands, headaches and cranial neuropathies may arise, impairing hearing, balance, speech and swallowing. 18 Contralateral involvement of cranial nerves may be seen.…”

Bilateral Cholesterol Granulomas of the Temporal Bone

“…Renamed giant cholesterol cysts, these lesions contain a brownish glistening mucoid fluid surrounded by a fibrous wall. Differentiation between a cyst and a solid lesion, which can occur in the same location, can be made by obtaining T 1 -and T 2 -weighted MRI images [2,3]. A cystic lesion will be bright on both images, whereas a solid lesion is only bright on the T 2 image.…”

Cholesterol granuloma of the temporal bone: a pathologic designation or a clinical diagnosis?

“…Although cholesterol granuloma is a pathologic term [31] used to describe a tissue response to cholesterol crystals, it is now also recognized as a clinical diagnosis [23,32,33] which is much more common than many had previously thought [32]. Cholesterol granuloma is now diagnosed in a timely fashion with the aid of CT and MRI scanning [32Á/38].…”

“…CT assists in defining the exact location and description of the lesion. A high-quality MRI should be able to differentiate preoperatively cholesterol granuloma from cholesteatoma or other neoplasms [33,39]. The CT appearance of cholesterol granuloma may be similar to that of cholesteatoma.…”

“…In contrast, cholesteatomas show iso-or hypo-density on T1-weighted images and a high signal intensity on T2-weighted images. Preoperative imaging is the key to the diagnostic evaluation of cholesterol granuloma [33]. Gherini et al [32], from the Otologic Medical Group of Los Angeles, presented 10 cases of cholesterol granuloma of the petrous apex and the correct diagnosis was made in 9 patients on the basis of CT findings.…”