Inverting papilloma of the temporal bone: Report of four new cases and systematic review of the literature

Objectives/Hypothesis Inverting papillomas (IPs) are benign locally invasive tumors that most commonly present within the sinonasal cavity. Temporal bone involvement is exceedingly rare, with fewer than 30 cases reported within the English literature to date. Study Design Case series and systematic review of the literature. Methods Four consecutive subjects with temporal bone inverting papilloma (TBIP) were treated, and an additional 28 previously published cases were identified in the literature. Main outcome measures were disease presentation, diagnostic evaluation, management strategy, and outcome. Results A total of 32 cases were analyzed. The median age at diagnosis was 54 years (mean 54.1; range 19-81 years). Nineteen (59%) patients had synchronous or metachronous sinonasal IP, whereas 13 (41%) had isolated temporal bone disease without sinus involvement. Over half of the patients undergoing microsurgical resection experienced at least one recurrence. Compared to patients with a history of sinus IP, subjects with primary TBIP were younger at time of presentation (44 vs. 58 years; P-=-0.012); were more commonly female (62% vs. 32%; P-=-0.15); and were less likely to have intracranial spread (8% vs. 26%; P-=-0.36), cranial neuropathy (8% vs. 26%; P-=-0.36), human papillomavirus positivity (11% vs. 57%; P-=-0.11), or associated carcinoma (0% vs. 47%; P-=-0.004). Conclusions Inverting papilloma of the lateral skull base is rare and can pose a significant therapeutic challenge. Primary lesions of the temporal bone appear to follow a less aggressive clinical course when compared to those arising in association with sinonasal disease. Gross total resection is the preferred method of treatment, when feasible, given the high rate of recurrence with subtotal resection and risk of associated malignancy. Level of Evidence 4.