Pathology: intramuscular myxoma

Hypocellular; spindle-stellate cells with loose fascicular pattern

Pale and eosinophilic cytoplasm with delicate wispy processes

Monomorphic ovoid nuclei; inconspicuous mitotic activity

Abundant myxoid stroma; delicate curvilinear vessels

DNA-seq: GNAS mutation (c.601C>T; p.Arg201Cys) 

Hypocellular; spindle-stellate cells with loose fascicular pattern

Pale and eosinophilic cytoplasm with delicate wispy processes

Monomorphic ovoid nuclei; inconspicuous mitotic activity

Abundant myxoid stroma; delicate curvilinear vessels

DNA-seq: GNAS mutation (c.602G>A; p.Arg201His) 

Lobulated and infiltrative; hypocellular; spindle-stellate cells with a loose fascicular pattern

Eosinophilic cytoplasm with delicate wispy processes 

Monomorphic ovoid nuclei; inconspicuous mitotic activity

Abundant myxoid stroma with occasional cystic spaces; delicate thin-walled vessels; scattered aggregates of macrophages 

Infiltrative; hypocellular; spindle-stellate cells with patternless distribution

Eosinophilic cytoplasm with delicate wispy processes 

Monomorphic ovoid nuclei; inconspicuous mitotic activity

Abundant myxoid stroma, with small cystic spaces; delicate curvilinear vessels; scattered macrophages

Infiltrative; hypocellular; spindle-stellate cells with a loose fascicular pattern

Eosinophilic cytoplasm with delicate wispy processes 

Monomorphic ovoid nuclei; inconspicuous mitotic activity

Abundant myxoid stroma, with occasional cystic spaces; delicate curvilinear vessels; scattered macrophages