PMC5859865_01
(a) Hematoxylin and eosin (H&E) stained mesenteric lymph node reveals effacement of nodal architecture by paracortical expansion of an atypical lymphoid population. Scattered small lymphoid follicles are noted (2x). (b) A CD20 immunohistochemical stain highlights sheets of monotonous, medium-sized cells, identifying the cells as B-lymphocytes (2x). (c) EBER, a nuclear stain for EBV-encoded RNA, is expressed by the B-lymphocyte population and scattered throughout the paracortical expansion, suggesting an EBV-related lymphoproliferative disorder (2x). (d) H&E staining of the bone marrow aspirate shows a hemophagocytic histiocyte (arrow), which contains a leukocyte and appears to be in the process of engulfing a red blood cell (100x).
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fig1
T-cell hyperplasia. The paracortical expansion was comprised of predominantly CD4-positive polymorphic T cells that stained positively for CD2, CD3, and CD5, with partial loss of CD7 (Figure 1(a)). A monotonous population of CD20-positive B cells was also identified that coexpress MUM-1 and was positive for EBER (Epstein-Barr virus encoded messenger RNA) (Figures 1(b) and 1(c)). This revealed marked hemophagocytic changes consistent with HLH (Figure 1(d)).