Abstract: Dermatofibrosarcoma protuberans in children is rare and often leads to missed diagnosis and misdiagnosis. This paper presents a case of skin lesions present at birth. A 2-year-old boy presented with a light purple patch, about the size of a broad bean, on the left buttock. Over the past two years,both the size and the number of these patches have gradually increased. Histopathological examination showed the tumor was located in the dermis and subcutaneous tissue. It was composed of spindle or short spindle cells, arranged diffusely or in a storiform pattern, the cells were atypical and nuclear division was seen. Immunohistochemical staining showed CD34 was positive, CD68, CD31, CK, S100 and EmA, and CD1a were negative. Ki-67 proliferation index was 2%.The diagnosis of dermatofibrosarcoma protuberans was made. The patient was treated with Mohs micrographic surger, and there was no recurrence during the one-year follow-up.

Key words: dermatofibrosarcoma, protuberans, child