Bilateral squamous cell carcinoma of the temporal bone: A report of two cases and a systematic review of the literature

Objective: two new cases of temporal bone squamous cell carcinoma (TBSCC) with a bilateral occurrence are presented. Furthermore, a review of the literature was performed and the yearly incidence was calculated. Methods: A systematic review of the literature was conducted using PRISMA guidelines. Results: Twenty-two more cases were found in literature. With a total of 24 cases, the calculated yearly incidence of bilateral TBSCC is 49:10^12 A history of chronic otitis or regional radiotherapy was found in respectively 50% and 12% of patients. In nine patients, the tumors developed synchronously (within 6 months) and in 13 metachronously. Conclusions: The calculated incidence is 89 times higher than mathematically expected considering the incidence of unilateral cases. An explanation might be a history of chronic otitis or prior radiotherapy. The tumor staging of both the first tumor group and the contralateral tumor group are similar to unilateral temporal bone squamous cell carcinoma series.