Fibrosarcoma, Myxoid type (Myxofibrosarcoma)
It is a low-grade malignant fibroblastic tumor with copious myxoid stroma (>50% of the tumor). The degree of cellularity, pleomorphism, and mitotic activity vary within the tumor. The image shows spindle cells with minimal atypia in a myxoid background. The tumor usually involves subcutis of distal extremities in elderly patients. Note the resemblance to benign lesions such as nodular fasciitis.