RESUMO
<p><b>OBJECTIVE</b>To investigate the clinicopathologic features of mantle cell lymphoma (MCL) and the significance of immunostaining for cyclin D1 in diagnosis.</p><p><b>METHODS</b>Clinicopathologic observation and immunohistochemical staining for CD20, CD45RO, cyclin D1, bcl-2, Ki-67, CD5 for 8 cases of mantle cell lymphoma were performed.</p><p><b>RESULTS</b>The 8 cases of mantle cell lymphoma consisted of 6 males and 2 females, aged from 43 to 78 years (mean 57 years). Histopathologically, MCL demonstrated architectural destruction by a vaguely nodular monomorphic lymphoid proliferation with vaguely nodular, diffuse or mantle zone growth patterns. Analogous to centrocytes, the lymphoma cells with slightly to markedly irregular nuclear contours showed moderately dispersed chromatin and a low mitotic figure. Three cases were transformed into highly aggressive blastoid variants. The tumor cells were positive for CD20, CD5, bcl-2 and cyclinD1 in all 8 cases and negative for CD45RO.</p><p><b>CONCLUSIONS</b>The clinicopathological features and special immunophenotypes were present in mantle cell lymphoma. This tumor can be differentiated from other small B-cell lymphomas on the basis of histopathologic features and positive cyclin D1 immunophenotype. The blastoid variant should also be differentiated from other variants.</p>