Sarcomatoid carcinoma of the tongue in chronic graft versus host disease: An unusual report

Sarcomatoid carcinoma (SC) occurs rarely in the oral mucosa, especially in the tongue. Conversely, chronic graft versus host disease (cGVHD) is a risk factor for secondary malignant tumors, especially oral squamous cell carcinoma (OSCC). This suggests that tumor formation caused by regulation of cGVHD is important for an effective understanding of SC. Herein, we report an unusual case of SC of the tongue in a patient with cGVHD. Short tandem repeat analysis using genomic DNA extracted from the tumor and lymphocytes of the patient was performed, and the loci of the donor and recipient were detected from the tumor locus. These data suggest that the SC was an undifferentiated carcinoma originating from donor cells that underwent epithelial mesenchymal transition. The clinical, pathological, and genomic features suggest an SC characterized by an undifferentiated aggressive OSCC occurring after cGVHD.