EBVMCU, a type of cancer, is a condition in which B lymphocytes infected with the EB virus proliferate abnormally, and it tends to occur in the oral cavity of patients taking the therapeutic drug methotrexate for rheumatoid arthritis, forming intractable ulcers. ..Since the pathological examination shows the same image as malignant lymphoma, it is difficult to distinguish it from high-grade malignant lymphoma (cancer of lymphocytes belonging to white blood cells).However, unlike malignant lymphoma, it heals spontaneously only by discontinuing oral methotrexate, and although it looks "cancer", it does not require anticancer drug treatment.Although the number of patients is increasing in Japan, where the population is aging, there are many unclear points about its pathological characteristics.

　Until now, the existence of two types of pathological features of EBVMCU was known, but analysis revealed the existence of two new types.In addition, EBVMCU genetic abnormalities occurred at the same frequency as malignant lymphoma.Therefore, it became clear that it is difficult to distinguish from malignant lymphoma only by pathological examination.For diagnosis, the history of treatment with immunosuppressive agents such as methotrexate for autoimmune diseases such as rheumatoid arthritis is the most important key for diagnosis of this disease.

　Regarding the results of this research on EBVMCU, "In order to make an appropriate diagnosis and avoid unnecessary anticancer drug treatment, doctors involved in rheumatism treatment, otolaryngologists and dentists involved in oral care, and pathology We hope that the pathologists and clinical laboratory technicians involved in the examination will be widely known, "says Professor Sato.

Paper information:[Modern Pathology] Clinico pathological analysis of 34 Japanese patients with EBV-positive mucocutaneous ulcer