Malignant fibrous histiocytoma of soft tissue: a population-based epidemiologic and prognostic study of 137 patients

Despite the fact that malignant fibrous histiocytoma was only first described as a class of tumor in the early 1960s, these cancers are the most common sarcomas of soft tissue. There have been relatively few research papers published that are devoted exclusively to these cancers. Also, some of the findings of these studies are inconsistent, which may be attributed to selection bias. Since often only the larger and more serious histiocytomas are referred to major medical centers, tabulations of data on these tumors by these medical centers are not representative of the full range of the cancers that actually occur. To provide an insight into the spectrum malignant fibrous histiocytomas as they occur in the population, a population-based study of 137 patients was conducted. While the average age was 64 years, the cancer occurred in patients as young as 22 years. The annual incidence of malignant fibrous histiocytoma was 0.42 cases per 100,000 people per year. Malignant fibrous histiocytoma occurs in a variety of histologic types, and the type plays an important role in predicting survival. The majority of such cancers have a mixture of pleomorphic (many shapes) and storiform (a matted, irregular pattern) histologic types. In the present study, 83 patients had storiform or pleomorphic tumors. These types are highly malignant with a chance of metastatic disease of about 50 percent. The five-year survival rate for the storiform-pleomorphic histiocytoma was 0.5, and was strongly associated with metastasis. In contrast, the five-year survival rate for the 53 patients with the myxoid histologic type was a perfect 1.0. While some previous studies found an association between survival and locoregional recurrence, the development of local recurrence did not influence survival in this study. (Consumer Summary produced by Reliance Medical Information, Inc.)