Figure 3

Mantle cell lymphoma in colonic biopsy showing infiltration of the lamina propria by a sheet of small cells with irregular nuclei with expression of cyclin D1. (a) Low power showing nodular infiltrate in lamina propria; H&E. (b) Intermediate power showing edge of a nodule with mild interstitial infiltration around glands but no lymphoepithelial lesion; H&E. (c) High power showing the characteristic cellular morphology with scanty cytoplasm, irregular/indented nuclear contours and absent nucleoli; H&E. (d) Nuclear staining for cyclin D1 is present in the lymphoma cells with epithelial and endothelial cell staining acting as internal control.