Reassessment of non-Hodgkin's lymphoma with a 'nodular' growth variant: A clinicopathologic study of follicular, mantle cell and marginal zone lymphomas prospectively diagnosed with multiparameter analyses

Although three subtypes of non-Hodgkin's lymphoma (NHL), follicular lymphoma (FL), mantle cell lymphoma (MCL) and marginal zone lymphoma (MZL), are now well recognized as independent categories, their biological behavior has not been fully compared. One of the reasons for this may be that subclassification by histological examination alone is often difficult since they all have a common variant of a 'nodular' growth pattern and occasionally show similar cytological morphology. Recently, we reviewed patients with FL, MCL and MZL, who were prospectively diagnosed, using multiparameter analyses with unfixed fresh biopsy materials. Of 407 NHL patients, 101 (24.8%) belonged to these three categories and 80 could be followed; FL (n = 27), MCL (n = 27) and MZL (n = 26). Twenty eight cases with diffuse large B-cell (DL-B) lineage lymphoma were selected as control at random. The frequency of the MCL patients with performance status (PS) 2 to 4 (41%) was significantly higher than MZL patients (4%) [P < 0.001]. The 3 year survival rate with FL, MCL, MZL and DL-B was 71.5%, 57.4%, 93.3% and 53.1%, respectively. The survival rate for MZL was significantly better than both FL (p = 0.048) and MCL (p = 0.0085). Significant differences were also found in the overall survival rates among the four risk groups as defined by the International Index [I₂](low, low-intermediate, high-intermediate and high; 97.4%, 79.6%, 39.4% and 18.2%, respectively). A multivariate analysis revealed that the International Index may be a significant predictor for short survival (p = 0.0001) in the patients with FL, MCL or MZL. These results suggest that MZL shows an apparently better prognosis than FL and MCL and is found to be a prognostically independent category. In contrast, the clinical outcome in MCL is the worst among the three subtypes and was closer to that of DL-B. The International Index can be applied to a wide spectrum of NHL, including MCL, MZL and FL, to and can predict prognosis in these cases.