Classification of Cholesteatoma According to Growth Patterns.

IMPORTANCE Several classifications of cholesteatoma exist, but there are controversies about their clinical application. OBJECTIVE To classify cholesteatomas and describe the prevalence of the subtypes. DESIGN, SETTING, AND PARTICIPANTS A cross-sectional comparative study of 414 ears in 356 consecutive patients with middle ear cholesteatoma and no history of ear surgery treated at a tertiary hospital was conducted from March 8, 2000, to March 30, 2015. Data analysis was conducted from March 30, 2014, to March 30, 2015. INTERVENTION Otoendoscopy was conducted, and findings for both ears were recorded. MAIN OUTCOMES AND MEASURES Cholesteatoma growth patterns were classified as anterior epitympanic, posterior epitympanic, posterior mesotympanic, 2 routes (both the pars flaccida and the pars tensa are involved), and undetermined. RESULTS Among the 356 patients in this study, mean (SD) patient age was 33.23 (19.81) years (range, 4-82 years), and 125 patients (35.1%) were female. The right ear was identified as the affected ear in 220 patients (61.8%). A total of 272 (65.7%) ears were from adults. Of the 414 ears that underwent otoendoscopy, posterior epitympanic (142 [34.3%]) and posterior mesotympanic (140 [33.8%]) were the most frequent types of cholesteatoma observed, followed by undetermined (67 [16.2%]) and 2 routes (57 [13.8%]). Anterior epitympanic type was the least frequent (8 [1.9%]). Posterior epitympanic cholesteatoma was more prevalent in adults (111 [40.8%]), whereas posterior mesotympanic cholesteatoma was more frequent in children (43.0%) (P < .001). Anterior epitympanic cholesteatoma was observed only in children. CONCLUSIONS AND RELEVANCE Classifying cholesteatomas according to the growth pattern (anterior epitympanic, posterior epitympanic, posterior mesotympanic, 2 routes, and undetermined) includes all existing types of cholesteatomas of the middle ear. In general, the prevalence of posterior epitympanic and posterior mesotympanic cholesteatoma were similar. Whereas anterior epitympanic and posterior mesotympanic cholesteatomas were more prevalent in children, posterior epitympanic cholesteatoma was more frequent in adults.