Unusual Presentation of a Pediatric Burkitt's Lymphoma With Infiltration of the Interatrial Septum.

Background: Burkitt's lymphoma (BL) is the most common subtype of non-Hodgkin lymphoma in children, typically presenting with extranodal masses in areas such as the abdomen, face, and neck. Cardiac involvement in BL is extremely rare, especially in pediatric patients, and has significant implications for diagnosis, management, and prognosis.

Case presentation: A 6-year-old male patient with Burkitt's lymphoma, presenting with an uncommon infiltration of the interatrial septum, is described. The patient initially presented with a painful right facial mass, bilateral periorbital edema, and a history of fever, weight loss, and lower limb pain. Imaging revealed extensive disease, including a right masticator muscle mass, mandibular infiltration, and multiple soft tissue and skeletal lesions, along with significant thickening of the interatrial septum. A diagnosis of Stage III Burkitt's lymphoma was confirmed through biopsy and immunohistochemical analysis. The patient was treated according to the ANHL1131 protocol, including Rituximab and multi-agent chemotherapy. Remarkably, the cardiac infiltration showed substantial regression on follow-up echocardiography after chemotherapy.

Conclusions: This case underscores the importance of a comprehensive cardiac evaluation in pediatric patients with Burkitt's lymphoma, particularly when presenting with atypical manifestations such as interatrial septum involvement. The findings demonstrate that systemic chemotherapy can effectively treat cardiac infiltration, even in complex cases with extensive disease. This report highlights the need for awareness of rare cardiac presentations in pediatric lymphoma and the critical role of advanced imaging modalities in diagnosis and management. Continuous monitoring and early implementation of cardioprotective strategies are essential to optimize outcomes in such cases.