Multifocal oral squamous cell carcinoma post haematopoietic stem cell transplantation: A case report.

Oral squamous cell carcinoma is considered a rare complication of post-haematopoietic stem cell transplantation (HSCT). Early detection of these lesions is further complicated by the overlapping clinical appearance and presentation of lesions associated with chronic graft versus host disease (cGVHD). We report a case of oral squamous cell carcinoma in a 33 year-old man who presented with severe intraoral pain on the lower left side of the cheek and jaw 19 months after undergoing HSCT for the treatment of underlying acute lymphoblastic leukaemia. He was previously treated with intravenous cyclophosphamide as a conditioning regimen for HSCT and later developed cGVHD of the liver, eyes, and gut, which resolved with treatment. Intraoral examination revealed two separate lesions. The first lesion presented as a raised oval nodular swelling with a well-circumscribed margin and irregular surface on the left buccal mucosa. A similar, but more extensive, lesion was noted on the left lingual gingiva and was associated with spontaneous bleeding. Biopsy revealed that both lesions were well-differentiated squamous cell carcinomas and were p16 positive. He underwent palliative radiotherapy but succumbed to his disease 3 months after initiation of treatment.