Malignant fibrous histiocytoma of the calf
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80 year old male patient with a malignant fibrous histiocytoma of the calf.
Left medial knee soft tissue tumor biopsy showing malignant fibrous histiocytoma with prominent myxoid component, please see comment
Final diagnosis comment:
Features of note include a dense spindle cell proliferation, vaguely fascicular, moderately pleomorphic, mitotically active, with prominent small interspersed myxoid areas. Less than 50% of the biopsy is myxoid. Necrosis is present, involving less than 50% of the tissue. Vimentin stain is positive, while keratin, S-100, caldesmon, actin, CD34, and BCL-2 are negative. MIB-1 stain shows a high proliferation index. The findings are consistent with malignant fibrous histiocytoma, precise subclassification and grading depending on the relative proportions of the myxoid component and degree of necrosis respectively in the tumor as a whole.