Synchronous bilateral idiopathic external auditory canal cholesteatoma: a case report and review of the literature

BackgroundExternal auditory canal cholesteatoma (EACC) is a rare pathological condition representing 0.1% of all new otologic cases. Bilaterality manifests in 10% of EACC cases. Similar disease processes include keratosis obturans (KO) and benign necrotizing otitis externa (BNOE). Diagnostic differentiation may not always be unexacting but does however influence management and eventual outcome. This study aims to briefly review the literature, describe an unusual case of synchronous bilateral primary EACC, and simplify the diagnostic challenges surrounding this disease.Case presentationA 66-year-old man with no relevant family history, no concurrent or intercurrent illnesses, having undergone no relevant surgery, and had visited the Department of Otorhinolaryngology regarding right-sided otorrhoea and aural pruritis 9 years ago. At the time, he was diagnosed clinically with KO. Nine years later after having defaulted follow-up, he presented again with the same symptoms. Oto-microscopy now revealed excavation of the posterior canal wall, keratinous desquamation, and an intact tympanic membrane. Oto-endoscopy demonstrated extension posteriorly into the mastoid segment of the temporal bone. Computed tomography evinced a soft tissue attenuating mass within the excavated sub-adjacent bone, with extension into the mastoid air cell system. The contralateral ear had a smaller epithelial defect of the canal floor with underlying tympanic plate erosion. A closed mastoidectomy with the reconstruction of the posterior canal wall was performed on the right ear. The left ear was managed conservatively with micro-suctioning and aural toilette. Six months post-surgery, however, the reconstructed posterior canal wall underwent necrotic breakdown. The contralateral lesion gradually progressed into a Naim et al. (2005) Stage III EACC.ConclusionThis case illustrates the diagnostic challenge presented by EACC and is unusual regarding its bilaterality. The importance of diagnostic differentiation, both in the management of this disease and in the prevention of its progression, is highlighted. The idea of oto-endoscopy as a routine clinical tool is introduced, and endoscopic images are compared to high-definition computed tomography scans of the affected temporal bones.