Atypical fibroxanthoma is an uncommon type of skin cancer that can clinically be mistaken for other types of skin cancer. Like other types of skin cancer, atypical fibroxanthoma is generally associated with aging, x-ray radiation and UV rays, such as through sun exposure. It is most often found on the scalp, face or neck, but can develop in other areas of the body, too. At times, a deeper variant of this tumor called malignant fibrous histiocytoma can be more problematic. They may both also be called undifferentiated pleomorphic sarcoma.​