Malignant fibrous histiocytoma at the site of a total hip arthroplasty

Malignant fibrous histiocytoma is the most frequent sarcoma in adults. Predisposing factors for malignant fibrous histiocytoma are Paget's disease, bone infarcts, malignant disorders of the hematopoetic system, or prolonged intake of corticosteroids. Malignant fibrous histiocytoma has been described as occurring with increasing frequency after endoprosthetic therapy and has been attributed to the implants or to their alloy constituents. Malignant fibrous histiocytoma at the site of an endoprosthesis of the hip constitutes a distinct rarity. To our knowledge, only 13 cases have been described to date. In this report, we present the case of a 66-year-old woman with rheumatoid joint disease. Eight years after primary endoprosthetic surgery, loosening of the implant with severe osteolysis of the surrounding bone required replacement surgery. Histopathologic evaluation of resected tissue revealed scar and granulation tissue and Grade 3 malignant fibrous histiocytoma. The patient died I year after revision arthroplasty because of diffuse pulmonary and cerebral metastases. In patients with loosening of a total hip endoprosthesis in combination with severe periprosthetic osteolysis an accompanying malignancy should be in the differential diagnosis. The histopathologic examination of the resected tissue should be obligatory.