What are Reed-Sternberg cells and variants?

Classic ones are large (14-45 microm) w/abundant pale cytoplasm and two or more oval lobulated nuclei containing owl-eye eosinophilic nucleoli. Some shrink during formaline fixation and processing leave empty space around nucleus, called Lacunar cells. Other variant is L&H and Popcorn cell w/fluffy lobulated nucleus containing fine chromatin and small nucleoli