Second primary squamous cell carcinoma arising in a skin flap: a case report and literature review on etiologic factors and treatment strategy.

The number of reports describing malignant tumors arising in flaps has been increasing recently. This report describes the case of a patient who had a second squamous cell carcinoma (SCC) in the center of the skin island of a forearm flap raised approximately 6 years previously. Histopathologic examination suggested human papillomavirus infection and "mucosalization" of the flap. In addition, the authors review previous cases, with special attention to etiologic factors and surgical strategies. There might be a causal relation between second primary SCC in the flap and the carcinogenic effect (chronic inflammation) induced by the environment surrounding the squamous epithelium of the flap. If environmental factors have greatly contributed to the occurrence of a tumor, there is a potential for tumor occurrence in the remaining flap. There also might be a potential for generating second primary SCC in these foci. The results suggested that total resection of the flap might be recommended in the surgical resection of second primary SCC arising in a flap.