Malignant Fibrous Histiocytoma Originating in the Short-term after Excision

ABSTRACT

MFH is rare with just a few thousand cases diagnosed each year. We report a case of right flank malignant fibrous histiocytoma (MFH) in the short-term after tumor excision. A 47-year-old woman visited hospital after being diagnosed with MFH. Resection margin was positive, so we planned for wide excision. While awaiting surgery, 1.5 cm sized new mass occurred adjacent to the incision site. The patient underwent wide excision. Postoperative pathologic findings observed a 1.0 cm diameter mass with infiltrative borders in the subcutaneous fat. It was composed of spindle or epithelial cell showing severe polymorphism. Many mitotic cells were observed including atypia. In immunohistochemical study, tumor cells were negative for smooth muscle actin, desmin, myoglobin, S100, cytokeratin, and positive for CD68, and thus diagnosed as pleomorphic MFH. With the purpose of improving local tumor control, radiation therapy was performed after wide excision.