In the enlarged cervical lymph node of a 14-year-old girl microscopy detected the following: tissue structure of the lymph node is disturbed, no lymphoid follicles, there are sclerotic areas and necrotic foci, cellular composition of the lymph node is polymorphous, there are lymphocytes, eosinophils, large atypical cells with multilobular nuclei (Berezovsky-Reed_sternberg cells) and large mononuclear cells. Make the diagnosis: