FIGURE 1

Morphological, phenotypic and cytogenetic features of mantle cell lymphoma (MCL). A, classic MCL with centrocytic cells surrounding an atrophic follicle (lymph node section, HES, 200). B, CD23 labeling of an uneven meshwork of dendritic cells and negativity of centrocytic cells (lymph node section, immunoperoxidase, 200). C, monotonous population of small centrocytic cells with irregular cleaved nuclei and scant cytoplasm (lymph node section, HES, 1000). D, CD5 labeling of both reactive T cells (strong signal) and neoplastic centrocytic cells (moderate signal); centrofollicular cells are not labeled (lymph node section, immunoperoxidase, 200). E and F, examples of low (+) and strong (+++) labeling for cyclin D1 protein (lymph node section, immunoperoxidase, 400). G, detection of t(11;14) by interphase fluorescence in situ hybridization (FISH) in areas of adequately separated cells (lymph node section, 400). H and I,examples of FISH patterns in normal nuclei (H; 2 reds, 2 green signals) and in t(11;14)+ (I; 1 red, 1 green and 2 yellow fusion signals; lymph node section, 1000). J, blastoid variant of MCL characterized by larger lymphoid cells with round nuclear contours, vesicular chromatin, and some nucleoli (lymph node section, HES, 1000). K, examples of CCND1 amplification (red signals) in addition to t(11;14) fusion signals in blastoid cell nuclei after FISH analysis (lymph node section, 1000). Note the presence of the different number of red and green signals.