Pathology: low-grade fibromyxoid sarcoma

Loose fascicles of spindle-stellate cells

Pale and eosinophilic cytoplasm

Monomorphic ovoid nuclei; inconspicuous mitotic activity

Giant collagen rosettes

IHC: MUC4

RNA-seq: FUS::CREB3L2 gene fusion

Variably cellularity; spindle-stellate cells with vague fascicular pattern

Scant pale and eosinophilic cytoplasm

Monomorphic ovoid nuclei; inconspicuous mitotic activity 

Myxoid-collagenous stroma with delicate curvilinear vasculature

IHC: MUC4

RNA-seq: FUS::CREB3L2 gene fusion

Hypocellular; spindle cells with loose fascicular-storiform pattern

Pale eosinophilic cytoplasm with long tapering processes

Monomorphic ovoid nuclei; inconspicuous mitotic activity

Prominent myxoid stroma; condensation of tumour around delicate curvilinear vessels 

IHC: MUC4

RNA-seq: FUS::CREB3L2 gene fusion

Hypocellular; spindle cells with loose fascicular-storiform pattern

Pale eosinophilic cytoplasm with long tapering processes

Monomorphic ovoid nuclei; inconspicuous mitotic activity

Prominent fibromyxoid stroma; condensation of tumour around delicate curvilinear vessels

IHC: MUC4

RNA-seq: FUS::CREB3L2 gene fusion

Hypocellular; spindle cells with loose fascicular-storiform pattern

Pale eosinophilic cytoplasm with long tapering processes

Monomorphic ovoid nuclei; inconspicuous mitotic activity

Prominent fibrous stroma; occasional ectatic thin-walled vessels 

RNA-seq: FUS::CREB3L2 gene fusion

Hypocellular; spindle-stellate cells with loose fascicular-storiform pattern

Pale eosinophilic cytoplasm with delicate tapering processes

Monomorphic ovoid nuclei; inconspicuous mitotic activity

Prominent myxoid stroma; occasional short thin-walled vessels 

RNA-seq: FUS::CREB3L2 gene fusion

Hypocellular; spindle-stellate cells with loose fascicular-storiform pattern

Pale eosinophilic cytoplasm with delicate tapering processes

Monomorphic ovoid nuclei; inconspicuous mitotic activity

Prominent myxoid stroma; occasional short thin-walled vessels 

IHC: MUC4

Cellular; spindle-epithelioid cells with vague fascicular pattern

Pale eosinophilic cytoplasm

Monomorphic ovoid nuclei; occasional mitotic activity

Areas of fibrous stroma; delicate curvilinear vasculature

IHC: MUC4

RNA-seq: FUS::CREB3L1 gene fusion

Cellular; spindle-epithelioid cells with vague fascicular pattern

Pale eosinophilic cytoplasm

Monomorphic ovoid nuclei; inconspicuous mitotic activity

Areas of fibrous stroma; delicate curvilinear vasculature

IHC: MUC4

RNA-seq: FUS::CREB3L2 gene fusion

Lobulated; variable cellularity; spindle-epithelioid cells with vague fascicular pattern

Pale eosinophilic cytoplasm

Monomorphic ovoid nuclei; occasional mitotic activity

Prominent hyalinized stroma forming so-called "pseudorosettes"; delicate curvilinear vasculature

IHC: MUC4

FISH: FUS-rearrangement

PMID: 9414192