Malignant fibrous histiocytoma and atypical fibroxanthoma in renal transplant recipients

Background: Allograft recipients are at increased risk for skin cancer. The incidence of cutaneous squamous cell carcinoma is 50-250 times higher than in the age-matched control population, and basal cell carcinoma is about 1 0 times more frequent. The incidence of Kaposi's sarcoma is increased 400 t o 500 times over that in a control population of the same ethnic origin. Ho wever, the incidence of other types of cutaneous sarcoma in organ allograft recipients is largely unknown. Clinical Observation: Within a 2-year-perio d, we observed 2 patients with cutaneous malignant fibrous histiocytoma and 1 patient with atypical fibroxanthoma among a cohort of 642 renal transpla nt recipients. For comparison, the incidence for dermatofibrosarcoma protub erans which is the commonest type of cutaneous sarcoma, is 0.45/100,000 per sons/year in the non-immunocompromised population. Our observation represen ts an incidence of 156/100,000/year (95% confidence interval CI 28-489/100, 000/year) for cutaneous malignant fibrous histiocytoma and of 78/100,000/ye ar (95% CI 4-368/ 100,000/year) for atypical fibroxanthoma. Conclusion: To our knowledge, this is the first report on an elevated incidence of cutaneo us malignant fibrous histiocytoma and of atypical fibroxanthoma in renal tr ansplant recipients. Future cohort studies on malignancies in organ allogra ft recipients should aim at defining this risk more exactly.