(A–C) Features of the bone marrow (BM) aspirate and biopsy showing hemophagocytic lymphohistiocytosis (HLH) and cytomegalovirus (CMV) staining. (A, B) BM aspirate showing histiocytic hyperplasia and prominent hemophagocytosis by activated histiocytes. Arrowheads indicate features suggestive of ongoing endocytosis (Wright-Giemsa stain, ×1,000). (C) BM core biopsy result showing positive immunohistochemical stain for CMV showing a large cell with intranuclear inclusions suggestive of CMV in the BM.