Oral Squamous Cell Carcinoma Secondary to Chronic Graft-versus-host Disease: Report of Three Cases.

Recently, the use of hematopoietic stem cell transplantation (HSCT) for the treatment of hematological malignancies has increased because of its favorable therapeutic outcomes. The most common complication of HSCT is chronic graft-versus-host disease (GVHD). GVHD is an immune response caused by donor-derived cells that recognize the recipient as a foreign body (non-self) and attack the recipient's cells. GVHD manifests as lichen planus-like mucosal lesions in the oral cavity, and there have been reports of its malignant transformation to oral squamous cell carcinoma (OSCC). Chronic GVHD-associated OSCC may exhibit more aggressive behavior and a poorer prognosis than those of OSCC in patients who did not undergo HSCT. Here, we report three cases of GVHD after HSCT that transformed into OSCC during follow-up, in which early treatment achieved favorable outcomes. It is important to explain the risk of malignant transformation in patients with chronic GVHD and oral mucosal lesions and to monitor their progression.