Inflammatory Fibrous Histiocytoma: An Important Variant of Malignant Fibrous Histiocytoma Highly Responsive to Chemotherapy

Inflammatory fibrous histiocytoma is a recently recognized variant of malignant fibrous histiocytoma. Patients managed with surgical excision or radiation therapy usually have had multiple recurrences, often with metastases. The disease is insidious but ultimately fatal. Four consecutive patients were treated with inflammatory fibrous histiocytoma with alkylating agents with or without anthracyclines and produced prolonged and sustained remissions. Inflammatory fibrous histiocytoma may be another highly chemotherapeutically responsive tumor that deserves active case identification for aggressive curative therapy. INFLAMMATORY FIBROUS histiocytoma is a distinct vari-ant of malignant fibrous histiocytoma. Pathologically, both tumors are composed of differing proportions of cells similar to histiocytes and fibroblasts, arranged in a storiform pattern with pleomorphic giant cells and in-flammatory cells (1, 2). Inflammatory fibrous histiocyto-ma is distinguished by the presence of a diffuse, at times intense, neutrophilic infiltration unassociated with tissue necrosis (1). Since inflammatory fibrous histiocytoma was originally reported, at least 18 patients with documented cases (Ta-ble 1) have been described (1, 3-12). Previous reports have described the pathologic features and natural histo-ry. The literature suggests that the tumor runs an insidi-ous but aggressive and ultimately fatal course. Conven-tional surgical and radiation treatments provide only transient responses, with local recurrences and distant metastases being the rule. Chemotherapy has been given either in patients with end-stage disease, or as single-agent treatment, and has not been effective. We recently reported successful combination chemotherapy in one pa-tient with inoperable inflammatory fibrous histiocytoma (6). Since then we have seen three other patients with either inoperable or recurrent inflammatory fibrous histi-ocytoma. We describe the response to chemotherapy of these four patients