Fig. 6.
Kappa-predominant plasmacytoid proliferation in a patient with a history of lymphoma: A patient with stage IV diffuse large B-cell lymphoma developed new FDG-avid lymphadenopathy concerning recurrent lymphoma (note: case has previously been published,55 new images were taken for this publication with permission). H&E sections (A, B) show an interfollicular expansion by numerous small lymphocytes, epithelioid histiocytes, and focal sheets of plasmacytoid cells variably positive for PAX5 (C), positive for CD79a (D), negative for CD138 (E), and positive for MUM1 (F) with marked excess kappa (G) light chain expression compared with lambda (H). However, molecular studies showed polyclonal immunoglobulin heavy chain gene (IGH) rearrangements, absence of clonal aberrancies by cytogenetics, and lymphadenopathy resolved over time without evidence of lymphoma recurrence.