Pathology: myxoinflammatory fibroblastic sarcoma

Multinodular; variable cellularity; epithelioid-spindle cells with patternless architecture

Abundant eosinophilic cytoplasm

Round-ovoid nuclei with macronucleoli ("virocyte-like"), occasional binucleation ("Reed-Sternberg-like") and moderate pleomorphism; rare mitotic activity

Areas of myxoid stroma; mixed inflammatory infiltrate, including neutrophils, eosinophils, histiocytes, lymphocytes and plasma cells

Scattered pseudolipoblasts

RNA-seq: TOM1L2::BRAF gene fusion

PMID: 28692601

Variable cellularity; epithelioid-spindle cells with patternless architecture

Abundant eosinophilic cytoplasm

Round-ovoid nuclei with macronucleoli ("virocyte-like") and moderate pleomorphism; rare mitotic activity

Areas of myxoid stroma; mixed inflammatory infiltrate, including neutrophils, histiocytes, lymphocytes and plasma cells

Scattered pseudolipoblasts