Pathology: RREB1::MRTFB positive mesenchymal neoplasm (emerging)

RREB1::MRTFB positive mesenchymal neoplasm 

• Hypocellular spindle-polygonal cells in vague fascicles and cords

• Pale eosinophilic cytoplasm 

• Round-ovoid with mild pleomorphism; inconspicuous mitotic activity 

• Prominent myxoid-collagenous stroma, with focal chondroid differentiation

• PMID: 29912715,  31991003, 35763541

This entity presumably represents extraglossal ectomesenchymal chondromyxoid tumour