Factors Related to Cholesteatoma Formation in External Auditory Canal Osteomas and Treatment Algorithm.

Objectives: Osteomas in the external auditory canal (EAC) can lead to stenosis, and impair epithelium migration and self-cleaning capability, thereby trapping keratinized epithelium and triggering the development of cholesteatoma. Our study aims to identify the risk of cholesteatoma development in patients with osteoma and proposes a stepwise approach to managing patients with EAC osteoma. Methods: The maximum diameter of the osteoma was measured in axial and coronal views on high-resolution computed tomography (HRCT). We calculated the relative obstruction ratio caused by the osteoma in the axial and coronal views. Prior to surgery, otoscopy was employed to identify pedicle formation. The patients were categorized into 2 groups based on the presence of cholesteatoma. Results: We identified 43 patients diagnosed with EAC osteoma. A total of 9 (20.9%) patients with EAC osteomas developed cholesteatoma and the other 34 (79.1%) did not. The maximum diameter of osteomas with and without cholesteatoma was 12.67 ± 4.09 and 7.67 ± 3.27 mm, respectively ( P < .001). In the group without cholesteatoma, 21 osteomas had pedicles while the other 13 did not. In the cholesteatoma group, 2 osteomas had pedicles and 7 did not ( P = .037). No difference was observed in the relative obstruction ratio between these 2 groups. Conclusions: Our findings indicate that larger osteomas are more likely to develop cholesteatoma, while the formation of a pedicle may reduce the occurrence of cholesteatoma. In symptomatic patients, preoperative evaluation, including HRCT and otoscopy, is vital for assessing the extent of the osteoma and the potential coexistence of cholesteatoma. These factors are critical for preoperative consultations and surgical planning.