Oral squamous cell carcinoma in a 7-year-old Brazilian boy.

Squamous cell carcinomas (SCCs) are amongst the commonest malignancies in adults but in paediatric patients are exceptionally rare, particularly those involving the oral mucosa. The aim of the present report is to describe the features of a gingival well-differentiated SCC in a 7-year-old Brazilian boy. Immunostaining for p53, Ki-67 and Mcm2 showed increased cellular proliferation compared with normal epithelium. In situ hybridization failed to identify human papilloma virus infection. Correct diagnosis of well-differentiated squamous carcinoma can be difficult in children and differentiation from pseudoepitheliomatous hyperplasia is essential to establish proper treatment.