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5 Cholesterol Granuloma
Cholesterol granuloma is a histologic term used to describe a foreign body, giant cell reaction to cholesterol crystals, and hemosiderin derived from ruptured erythrocytes. Cholesterol granuloma is thought to arise from obstructed drainage and insufficient aeration of cellular compartments of the temporal bone. This leads to reabsorption of air, negative pressure, mucosal edema, and hemorrhage. It can be present in the middle ear, mastoid, or petrous apex. Generally, patients with tympanomastoid cholesterol granuloma have a long history of recurrent otitis media or otitis media with effusion. They also complain of conductive hearing loss, and on otoscopy the tympanic membrane appears bluish in color. In some cases, where granulation tissue is more prevalent, cholesterol granuloma can present as a retrotympanic reddish-brown mass that may cause bulging of the tympanic membrane, thus mimicking a glomus tumor. In these cases, a computed tomography (CT) scan is sufficient to clear any doubts. A cholesterol granuloma rarely causes bone erosion. On the contrary, bone erosion is characteristic
of glomus tumors causing destruction of the jugular hypotympanic septum with an irregular "moth-eaten" contour.
In the initial phases, before cholesterol granuloma is formed, it might be sufficient to insert a ventilation tube, thus preventing further development of the granuloma. When the granuloma has already been formed, it is necessary to perform a tympanoplasty with mastoidectomy that opens the intercellular septae with subsequent aeration of the middle ear and mastoid.
Figure 5.1 Right ear. Typical blue tympanum caused by cholesterol granuloma. The blue color is due to hemosiderin crystals. The granuloma involves not only the middle ear but generally extends into the mastoid air cells.
Figure 5.2 Blue tympanum caused by cholesterol granuloma. An epitympanic retraction due to eustachian tube dysfunction is also present.
Cholesterol Granuloma |
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Figure 5.3 Cholesterol granuloma associated with an |
Figure 5.4 Characteristic blue color of the tympanic mem- |
inflammatory polyp that leads to bulging of the tympanic |
brane caused by a cholesterol granuloma. |
membrane. |
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Figure 5.5 Axial CT of the case described in Figure 5.4. The |
Figure 5.6 Coronal CT scan of the same patient. |
granuloma and the effusion are present in the middle ear and |
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mastoid without causing any bony erosion. The ossicular |
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chain (malleus and incus) is intact and the intercellular septae |
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in the mastoid are preserved. |
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36 5 Cholesterol Granuloma
Figure 5.7 Left ear. A 17-year-old male patient complained of conductive hearing loss of 1 year duration accompanied by left nasal obstruction. Otoscopy revealed the presence of a left cholesterol granuloma. Rhinoscopy showed the presence of a nasopharyngeal swelling that extended into the left nasal cavity. The swelling was suggestive of a juvenile nasopharyngeal angiofibroma.
Figure 5.8 CT, coronal view. Involvement of the nasopharynx and the sphenoidal sinus.
Figure 5.9 Magnetic resonance imaging (MRI) of the same case, coronal view, showing the extension of the angiofibroma.
Figure 5.10 MRI of the same case, sagittal view, showing the extension of the tumor from the ethmoid to the rhinopharynx pushing the soft palate.
Figure 5.11 MR I of of the middle ear and can be observed.
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the same case, axial view. Involvement Figure 5.12 The angiofibroma was removed, after being mastoid by the cholesterol granuloma embolized, using a midfacial degloving approach,
Figure 5.13 Postoperative CT (1 year) confirming the total tumor removal.