Plasmacytoma-like lesion in the tonsil (case 5). (A) Architecture of the tonsil is completely effaced by sheets of atypical plasma cells. (B) The majority of plasma cells are large with prominent nucleoli. In situ hybridization for κ (C) and λ (D) shows κ light-chain restriction. 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.