Mesenchymal chondrosarcoma

Nests and sheets of small round-polygonal cells

Scant eosinophilic cytoplasm

Hyperchromatic round-ovoid nuclei with mild-moderate pleomorphism; inconspicuous mitotic activity

Interspersed bands of hyaline cartilage; prominent thin-walled branching vasculature

IHC: SATB2

RNA-seq: HEY1-NCOA2 gene fusion

Sheets of small round-polygonal cells

Scant eosinophilic cytoplasm

Hyperchromatic round-ovoid nuclei with mild-moderate pleomorphism; inconspicuous mitotic activity

Interspersed bands of hyaline cartilage

RNA-seq: HEY1-NCOA2 gene fusion

Sheets of small round-polygonal cells

Scant eosinophilic cytoplasm

Hyperchromatic round-ovoid nuclei with mild-moderate pleomorphism; inconspicuous mitotic activity

Interspersed bands of hyaline cartilage

RNA-seq: HEY1-NCOA2 gene fusion

Sheets of small round-polygonal cells

Scant eosinophilic cytoplasm

Hyperchromatic round-ovoid nuclei with mild-moderate pleomorphism; inconspicuous mitotic activity

Interspersed bands of hyaline cartilage

RNA-seq: HEY1-NCOA2 gene fusion

Sheets of small round-polygonal cells

Scant eosinophilic cytoplasm

Hyperchromatic round-ovoid nuclei with mild-moderate pleomorphism; inconspicuous mitotic activity

Interspersed bands of hyaline cartilage

RNA-seq: HEY1-NCOA2 gene fusion