Risk factors for occurrence and progression of external auditory canal cholesteatoma

External auditory canal cholesteatoma (EACC) is characterized by retained squamous debris within the external canal and variable amounts of localized bone destruction. The etiology of primary EACC remains incompletely understood. This study was conducted to analyze the clinical features and backgrounds of patients with primary EACC and to clarify the risk factors for the occurrence and progression of EACC.

Sixty-nine ears of 62 patients diagnosed with primary EACC were included in this study (EACC group). Additionally, 74 ears of 60 patients with chronic otitis media (COM) with perforation who underwent tympanoplasty or myringoplasty were included as controls (COM group). We retrospectively investigated the clinical features, life history, and medical history of the patients in both groups. In addition, to investigate the risk factors for progression of EACC, we compared the clinical features and medical history of patients with stage IV (advanced) disease versus stage I + II (mild) disease.

The inferior wall of the bony canal was the main structure affected in patients with primary EACC of all stages. The following factors were significantly more common in the EACC than COM group: older age, female sex, left-sided disease, osteoporosis, renal dysfunction, anemia, and treatment with bisphosphonates. Among these, the most significant factor associated with EACC was renal dysfunction (odds ratio, 11.4; 95 % confidence interval, 2.32-55.9). The significant factors observed in patients with stage IV disease were younger age, male sex, posterior wall involvement, and otorrhea. Surgical treatment was required for more than half of the patients with stage III and IV EACC.

Patients with renal dysfunction are at risk of primary EACC. In particular, younger patients and relatively younger elderly patients with posterior wall involvement have a risk of progression to advanced-stage EACC. Canalplasty should be considered in patients with EACC who have these risk factors to prevent progression to advanced-stage disease.