The misdiagnosis of external auditory canal carcinoma.

External auditory canal (EAC) carcinomas are frequently misdiagnosed. The aim of this study was to conduct a review of misdiagnosed cases and analyze the factors involved. This study was a retrospective assessment. Eighteen of 44 EAC carcinoma cases seen at the Eye and ENT Hospital were misdiagnosed. All medical records were retrospectively analyzed for the age, sex, presenting symptoms, type of misdiagnosis, computed tomographic (CT) or magnetic resonance imaging (MRI) findings, stage of the cancer, surgical approach, histopathological examination, adjunctive therapy (postoperative radiotherapy) and outcomes of treatment. Six cases were misdiagnosed as otitis media, five cases were misdiagnosed as otitis externa, and two cases were misdiagnosed as external auditory canal cholesteatomas. Other misdiagnoses were stenosis of the EAC, ear neuralgia, furuncle of the EAC, benign neoplasm of the EAC and pre-auricular fistula. Our analyses suggest that a biopsy should be conducted to obtain a histopathological diagnosis if an EAC carcinoma is suspected, in case otitis media or otitis externa does not respond to routine anti-bacterials. Head and neck MRI should be used to explore the involvement of soft tissues. Patients with bloody ear discharge and otalgia, particularly with temporal bone erosion seen in a CT scan, are highly likely to have a malignant carcinoma of the temporal bone.