A 7-year-old boy, who lived for 5 years in one of the African countries, has developed mandibular enlargement. Trephine biopsy detects the following in the biopsy material: diffuse infiltration with medium-sized lymphoid cells that have round or oval nuclei and numerous mitotic figures, among which there are large light-colored macrophages that contain apoptotic bodies. Sternal puncture and peripheral blood tests detect no significant changes. What is the most likely diagnosis in this case?