[Low-grade fibromyxoid sarcoma: analysis of 8 cases].

The diagnosis of low-grade fibromyxoid sarcoma was made in 8 patients. The lesions were 2-17 cm in the lower extremities and trunk. One patient had a long history of painless subcutaneous and intramuscular mass (median 1 year). All tumors showed predominantly the typical hypocellularity and cytologic features of typical low-grade fibromyxoid sarcoma; however, the areas of hypercellularity and nuclear enlargement and hyperchromatism were identified. No necrosis and mitotic activity less than 2 mf/50 HPF were present. Ultrastructurally, the tumor composed of neoplastic fibroblasts. No other cell differentiation was identified. Immunohistochemically, the neoplastic cells showed a positive response to vimentin and fibroblast antigen; no muscle-specific antigens were revealed. The Ki-67 labeling index with MIB-1 ranged 2-6%.