Polymorphous EBV+ Lymphoproliferative Disorder Arising in Immune Deficiency

Lessons From the Friday Unknowns

The patient is a 61-year-old female with a history of CD5 negative, CD10 negative B-cell lymphoma. The patient received 6 cycle of R-CHOP. Recent follow-up PET/CT showed interval development of hypermetabolic change in transverse colon and cecum, could be related to lymphoma recurrence, and multiple bilateral pulmonary nodules with variable degree of hypermetabolism could be related to infection and less likely lymphoma.

The specimen showed colonic mucosa with marked lymphohistiocytic infiltration and very focal necrosis. The lymphocytes are predominantly small, scattered and focal clusters of large cells also identified.

Immunohistochemical stains for CD19, CD20, CD22, and PAX5 highlighted a few scattered small and large B cells, one lymphoid follicle, and focal large clusters of large cells at the surface of one fragment.

Lymphocytes in the germinal center of the lymphoid follicle were positive for CD10, BCL6 but negative for Bcl-2 and with high Ki-67 proliferation rate, consistent with reactive follicle.

Bcl-2 and BCL6 are positive in a subset of lymphocytes. CD10 stains occasional large cells. CD3 stains diffusely scattered small T cells with no loss of CD2, CD5 and CD7, with normal CD4 and CD8 subsets. CD43 stains small T cells and sunset of B cells, including the large B cells. CD68 stain many histiocytes.

Ki-67 show overall proliferation rate of 30% overall and up to 50% in the clusters of large cells. CD30 stains rare medium to large lymphocytes. CD15 stains neutrophils. CD45 is diffusely positive, including the large cells. In situ hybridization for EBER is positive.