A 54-year-old male underwent open excision of a well organizing hematoma in the hip. 15 years ago, the patient had had a transfemoral angiography because of intracerebral hemorrhage. This mass had grown quiescently to the size of 20 cm and was located overlying incidental osteochondroma in the proximal femur. Therefore, physical examination and image modality were suspicions of malignancy. In the present study, we report a very huge and old hematoma mimicking soft tissue malignancy.