A 30-year-old woman has a dull blue-grey tympanic membrane with a fluid level behind it and mild conductive hearing loss. Myringotomy releases dark brown, viscous fluid containing shimmering golden crystals on microscopy. There is no keratin debris. The most likely diagnosis is:

• A Cholesteatoma
• B Glomus tumour
• C Cholesterol granuloma ✓
• D High jugular bulb

Explanation

Cholesterol granuloma results from impaired ventilation of the middle ear cleft causing vacuum, haemorrhage and breakdown products that crystallise as cholesterol, giving the blue drum appearance and dark brown 'motor oil' fluid with birefringent cholesterol crystals. It is a sterile inflammatory process without keratin. Cholesteatoma is distinguished by pearly white keratin squames against the drum, glomus tumour by a vascular retrotympanic mass with pulsation, and high jugular bulb by its bluish floor-of-cavity position without fluid.

Reference: Dhingra, Diseases of Ear, Nose and Throat, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.