Previous injuries or scars as risk factors for the development of basal cell carcinoma.

Basal cell carcinoma (BCC) is the most common malignant tumour in humans and most occur in elderly people. The pathogenesis of BCC is directly related to exposure to ultraviolet radiation in sunlight, but trauma is also mentioned occasionally. As well as one published series, several single cases have been reported. Our aim in the present study was to assess any possible relation between the development of BCC and trauma in a series of 92 patients, 12 of whom (13%) gave a history of previous injury. These lesions either developed directly after a sharp or blunt injury or in the scar tissue that had resulted from previous surgical incisions, burns, or dog bites. The male:female ratio was higher in the injured group (10:2) than in the uninjured group (44:36), but not significantly so (p = 0.11). Morphoea-like basal cell carcinomas were more common in the injured group (n = 91) (p = 0.06). We conclude that trauma might be considered as another aetiological agent for BCC.