Myxofibrosarcoma is recognized as a malignant neoplasm of fibroblastic origin with increased prevalence in the elderly, presenting as nodules or tumors that may extend to the dermis and skeletal muscle, preferably in the lower limbs. Histologically it is characterized by a proliferation of spindle cells in a myxoid stroma. Myxofibrosarcoma has a high potential for local recurrence and metastasis, mainly when it presents a high or intermediate histological grade. We report the case of an eighty-four year old patient with a difficult diagnosis of a highly aggressive tumor.