Surgical decision criteria: Bednar tumour of the foot in a child.

An 8-year-old boy was admitted for excision of a putative 'blue nevus' on the left foot. Histological examination and immunohistochemistry revealed a Bednar tumour, the pigmented variant of dermatofibrosarcoma protuberans. Surgical options considered by a multidisciplinary team included wide local excision, Mohs micrographic surgery or a staged excision with examination of several histological sections. The third alternative procedure was chosen after consideration of tumour and patient factors to achieve the best possible clinical, cosmetic and functional outcome. After the final surgical procedure with resection of the third metatarsal bone, all peripheral margins were free of tumour, and the interdigital space was reconstructed with a pedicled pulpa flap. Three years after surgery, there was no tumour recurrence, and further long-term follow-up for this patient will be provided.