Atypical plasma cell hyperplasia in the lymph nodes (case 3). (A) The lesion is characterized by sheets of plasma cells expanding the interfollicular areas admixed with small lymphocytes, plasmacytoid lymphocytes, immunoblasts, and histiocytes. (B) Plasma cells range from morphologically mature to atypical, enlarged forms with nucleoli. In situ hybridization for κ (C) and λ (D) shows similar numbers of positive cells. Panel A, H&E staining; original magnification, 200×. Panel B, H&E staining; original magnification, 400×. Panels C and D, in situ hybridization; original magnification, 200×. Slides were scanned using Ventana iScan Coreo scanner (Ventana Medical Systems Inc), and Image Viewer Version 3.1.1. program was used to capture the images. Final image preparation was performed with Adobe Photoshop CS5 Extended Version 12.1x64.