Keratin-positive fibrotic extraskeletal myxoid chondrosarcoma: a close mimic of myoepithelial tumor.

We identified a small subset of EMCs characterized by keratin expression and prominent stromal fibrosis. This histological pattern must be recognized in the differential diagnosis of myoepithelial tumors because misclassification may lead to the erroneous prediction of tumor behavior and may alter patient management. NR4A3 genetic analysis should be considered even in the face of keratin expression and prominent stromal fibrosis.