Proceedings of the International scientific and practical conference ―Modern Science: Challenges and Perspectives‖ (February 9-11, 2026) / Publisher website: www.naukainfo.com. - London, United Kingdom, 2026. - 121 p.

101 examination of a lymph node biopsy revealed reactive hyperplasia with expressed immunoblastic transformation and the presence of CD30-positive cells; Hodgkin lymphoma was excluded. A multidisciplinary team approach is recommended to monitor the clinical course, laboratory data, and to guide therapeutic decision- making. In the absence of positive dynamics in patients with persistent EBV infection and lymphadenopathy, repeat biopsy is recommended. Keywords: Epstein–Barr virus (EBV) infection, oncogenic potential, lymphoproliferative disorder, CD30-positive cells, lymphadenopathy, children. Introduction. Lymphoproliferative diseases (LPDs) are characterized by uncontrolled proliferation of lymphocytes, leading to autonomous expansion of immune cell populations, lymphocytosis, lymphadenopathy (LAP), and involvement of extranodal sites, particularly the bone marrow. These processes occur when the physiological mechanisms of immune control over T- and B-lymphocyte proliferation are disrupted. Primary care physicians most often encounter clinical manifestations of lymphoproliferative processes in the form of LAP - enlargement of lymph nodes (LNs) without signs of inflammation - which accompanies many diseases and requires careful differential diagnosis. Approximately 55% of children under the age of 10 experience LAP, which in most cases is localized and self-limiting. Persistent generalized LAP (involving more than two anatomical regions, excluding the inguinal region, persisting for more than 3 months, and with lymph node size greater than 1 cm) is observed in approximately 18% of patients [1]. Lymphadenopathy in children aged 3–10 years is often clinically insignificant, does not require treatment, and represents a benign process, most commonly of bacterial or viral etiology. However, a number of conditions should be considered in boys presenting with LAP, including congenital EBV infection or severe infectious mononucleosis complicated by hemophagocytic lymphohistiocytosis; EBV- associated hemophagocytic lymphohistiocytosis or that associated with other viral infections (cytomegalovirus, adenovirus, varicella, influenza);