Cutaneous Epithelioid Myxofibrosarcoma Arising in a Face: Case Report and Literature Review.

Myxofibrosarcoma is a malignant fibroblastic neoplasm characterized by cellular pleomorphism, myxoid stroma, distinctive curvilinear vessels, nonspecific immunophenotype, and complex karyotype. The epithelioid variant is a rare subtype composed of atypical cells featuring abundant eosinophilic cytoplasm and vesicular nuclei, closely mimicking nonmesenchymal malignancies. We report an exceptionally rare case of cutaneous epithelioid myxofibrosarcoma on the face of a 70-year-old man. The patient presented with a progressively enlarged cheek mass. Histopathologic examination revealed a dermal and subcutaneous tumor with a multinodular growth pattern and significant heterogeneity. It featured peripheral low-grade areas with myxoid stroma and curvilinear vessels and a central high-grade component (>50%) composed of solid sheets of epithelioid cells with severe nuclear atypia, prominent macronucleoli, and a high mitotic rate (>20 mitoses per 10 HPF). Tumor cells were focally positive for smooth muscle actin but negative for melanocytic, epithelial, myoepithelial, and lymphoid markers. CD34 highlighted the characteristic curvilinear vasculature of the tumor. Molecular analysis showed no mutations in BRAF, NRAS, or KIT genes, ultimately resulting in the diagnosis of high-grade epithelioid myxofibrosarcoma (FNCLCC grade 3). No recurrence or metastasis occurred within 9 months of follow-up. This case underscores the diagnostic challenge of cutaneous sarcomas in the head and neck region and highlights the necessity of a multimodal approach for an accurate diagnosis.