Unlike “typical” cases of conventional head and neck chondrosarcoma, the STM chondrosarcoma showed loss of SMARCB1 expression, focal to diffuse immunostaining for epithelial markers, including EMA, CAM 5.2 and CK AE1/AE3, and 12p duplication with absence of IDH1/2 mutations. This evidence concerns the gene SMARCB1 and chondrosarcoma.