Cholesterol granuloma.

A 72-year-old woman with multiple medical problems--including diabetic neuropathy, osteoporosis, and multiple episodes of deep vein thrombosis--presented with a loss of hearing in her left ear. The patient was taking several medications, including 80 mg/day of subcutaneous enoxaparin and 81 mg/day of aspirin. Otoscopy showed that her left eardrum was blue. Audiometry revealed a conductive hearing loss. She had no history of head trauma or barotitis. A spontaneous hemotympanum was suspected, and the patient was told that her condition might resolve spontaneously.

One month later, the drum was still blue (figure), and the patient had a conductive hearing loss; therefore, a myringotomy was performed. The patient's symptoms resolved immediately. Thick fluid with gold-yellow specks was aspirated, and a diagnosis of a cholesterol granuloma was made. At the 18-month follow-up, she showed no evidence of recurrence, and her ear was dry.

In patients with blue drum, otoscopy shows that some or all of the tympanic membrane is blue--usually a shade of steel blue. Several different factors can cause the tympanic membrane to assume a blue color, including a true hemotympanum, an idiopathic hemotympanum secondary to a cholesterol granuloma, long-standing secretory otitis media, a dehiscent high-riding jugular bulb, and occasionally a chemodectoma. (1)

A true hemotympanum often manifests as a fluid level behind the tympanic membrane; it is generally associated with trauma, particularly a temporal bone fracture. When a temporal bone fracture is suspected, computed tomography is recommended.

According to Sade, what we consider to be a case of idiopathic hemotympanum is actually a case of granular mastoiditis in which a cholesterol granuloma dominates the pathologic picture; it appears in the tympanic cavity and imparts a steel-blue color to the drum. (1) It is simply the amount of cholesterol granuloma that distinguishes the blue drum from any chronically underaerated middle ear.

Cholesterol granulomas have a characteristically bright appearance on T1 - and T2-weighted magnetic resonance imaging. Before performing a myringotomy, a dehiscent jugular bulb and glomus tumor must be excluded.

Main et al were successful in producing cholesterol granulomas in squirrel monkeys by obstructing the eustachian tube for 6 to 12 months. (2) Although some authors recommend mastoidectomy in conjunction with a ventilation tube for resolution of the condition, we did not perform a mastoidectomy on our patient.

References

(1.) Sade J. The blue drum (idiopathic hemotympanum) and cholesterol granulomas. In: Sade J, ed. Secretory Otitis Media and Its Sequelae. Vol. 1. Monographs in Clinical Otolaryngology. New York: Churchill Livingstone, 1979.

(2.) Main TS, Shimada T, Lira DJ. Experimental cholesterol granuloma. Arch Otolaryngol 1970;91:356-9.

From the Department of Otolaryngology, University of Texas Health Science Center at Houston.