A microscopic examination of the enlarged neck gland of a 14-year-old girl revealed destruction of the tissue structure of the node, absence of the lymph follicles, sclerotic and necrosis parts. Cell constitution of the node is polymorphous, lymphocites, eosinophi-les, atypical cells of the large size with multiple-lobule nuclei (Beresovsky-Shternberg cells) and onenucleus large size cells are observed. What is the most likely diagnosis?