A rare case of combined external auditory canal cholesteatoma and keratosis obturans in different ears

Traditionally, it was presumed that cholesteatoma of the external auditory canal and keratosis obturans were the same condition. Recent research has found that these are two distinct diseases. Cholesteatoma of the external auditory canal often presents as a unilateral lesion; whereas keratosis obturans is mostly a bilateral leasion, which is a critical aspect of differential diagnosis. We have searched for literature on both nosologies and their conservative and surgical treatment approaches and studied a potential progression from keratosis obturans to cholesteatoma of the external auditory canal and their combination. The paper describes a rare case of combination of these nosologies in a single patient, i.e. keratosis obturans in one ear and cholesteatoma of the external auditory canal in the other, observations and treatment of this condition over 25 years. We confirmed the views of numerous Russian and foreign authors that long-term conservative treatment of keratosis obturans is both possible and effective. However, it requires high-quality follow-up and ear care accompanied by minimally invasive exenteration once in 4–6 months. Cholesteatoma of the external auditory canal requires different surgical treatment based on the disease’s progression. Cholesteatoma of the external auditory canal may develop in one ear alongside keratosis obturans in the observed ear. Moreover, progression from keratosis obturans to cholesteatoma in the external auditory canal may be caused by ear injury, inappropriate care by the patient or a medical professional, especially in unfavorable environment and with contributing factors at play.