Grade 4 Mucositis Secondary to Methotrexate Use in a Pediatric Patient With Stage IV Burkitt Lymphoma: A Case Report.

Non-Hodgkin lymphoma (NHL) is a monoclonal neoplastic proliferation of lymphoid cells that can arise in different components of the immune system. Methotrexate (MTX), an antifolate agent, is widely used in the treatment of malignancies and autoimmune diseases. One of its most significant toxicities is gastrointestinal mucositis, a dose-dependent mucosal injury that can involve the entire alimentary tract and manifest as painful oral and intestinal ulcerations. We present the case of a pediatric patient with stage IV Burkitt lymphoma who developed severe mucocutaneous toxicity after MTX administration. This report also reviews risk factors associated with heightened toxicity and highlights strategies for prevention and management of MTX-induced oral mucositis, with particular emphasis on the clinical importance of delayed drug clearance, which increases the risk of multisystem toxicity and mortality.