Actinomycosis of the Middle Ear Mimicking Cholesteatoma: A Case Report and Literature Review.

Actinomycosis is a rare infection of the middle ear. Actinomyces is an anaerobic, filamentous bacterium causing granuloma formation and suppurative infection. We present a young male with a nine-month history of unilateral, yellow-coloured otorrhoea and hearing loss. Swabs showed no growth, with the infection not responding to oral or topical antibiotics. Computed tomography of temporal bones was consistent with cholesteatoma and ossicular disruption. Surgical exploration revealed a yellow, cystic mass within the middle ear. Cortical mastoidectomy and washout were performed. Histological diagnosis confirmed Actinomyces clusters with positive gram stain. Actinomycosis of the middle ear typically presents as chronic otitis media. It likely reaches the middle ear via the eustachian tube. It is often misdiagnosed due to culture insensitivity; however, clinical suspicion can aid labs in providing an optimum culture environment. Tympanomastoidectomy allows for histopathological diagnosis. Surgical resection should be followed by a prolonged course of antibiotics.