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Epithelioid malignant peripheral nerve sheath tumors (MPNST) have plump polygonal cells with abundant eosinophilic cytoplasm. Epithelioid MPNST of skin may show HMB-45 immunoreactivity and be mistaken for desmoplastic or spindle cell melanomas. MPNSTs that arise by malignant transformation of schwannomas are of epithelioid type.

The epithelioid tumor cells in this case show lobular architecture separated by loose myxoid stroma. Many of the lobules are composed of tumor cells arranged in a perivascular distribution. They have vesicular nuclei and prominent nucleoli.

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