We describe an allogeneic bone marrow (BM) recipient who developed aggressive, metastasizing squamous cell cancer (SCC) of the skin, and discuss possible risk factors in the development of this secondary solid tumor. The patient had been treated with cyclosporine (CsA), methyl-prednisolone and thalidomide for 3 years because of extensive de novo chronic cutaneous GVHD occurring 1 year after BMT. Ten years after BMT a locally invasive and metastasizing SCC occurred on the patient's neck, and diagnosis was confirmed by H&E histopathology and cytokeratin-immunohistochemistry. Analysis of genomic DNA did not reveal p53 mutations nor were HPV sequences detectable. Risk factors included conditioning for BMT with total body irradiation (TBI) and cyclophosphamide (Cy), immunosuppressive treatment for GVHD, and extensive exposure to UV radiation before and after BMT. Despite surgery and adjuvant chemotherapy with 5-fluorouracil (5-FU) the patient died 1 year after the diagnosis of SCC.