The relationship between numerous histologic variables and survival was investigated in 54 consecutive lesions of specific skin infiltrates of B-cell chronic lymphocytic leukemia (B-CLL) from 27 patients (16 males and 11 females, mean age 65 years, range 42-83 years). All patients were followed for up to 204 months or until death. Histopathologically, the infiltrates showed a patchy perivascular (35%), diffuse (31.5%), nodular (31.5%) or bandlike (1.9%) pattern. In 28% of the cases, an admixture of reactive cells within the infiltrate including eosinophils, histiocytes, neutrophils and plasma cells was observed. Cytomorphologically, small B-lymphocytes with condensed chromatin predominated in most infiltrates. However, some biopsies showed a small but significant number of medium- or large-sized neoplastic cells of the B-lymphocyte lineage with variable cytomorphological features. In a multivariate analysis, several histologic parameters within the infiltrates were found to show a significant association with long survival, namely, an infiltrate of moderate density, a nodular pattern, involvement of the lower dermis only, and presence of predominantly small B-lymphocytes (more than 95%) with condensed chromatin. Histologic variables that independently correlated with relatively short survival included an infiltrate of severe intensity, a diffuse pattern, epidermal changes (especially acanthosis and ulceration), medium-sized and large B-lymphocyte (more than 5%), and reactive cells within the infiltrate (neutrophils, eosinophils, and plasma cells). Overall analysis of our results showed two histologic patterns with a significant prognostic impact (p < 0.01; z = 5.4). Pattern I (33 biopsies) correlated with relatively long survival (2-year survival rate; 97%) and consisted of infiltrates showing predominantly small B-lymphocytes (more than 95%) without reactive cells or epidermal changes. Pattern II (21 biopsies) indicated short survival (2-year survival rate; 49%) and included all the rest of the biopsies i.e., infiltrates with medium- and large-sized B-lymphocytes (more than 5%), admixture of reactive cells, and epidermal changes. Results from our study suggest that histologic features in specific skin infiltrates of B-chronic lymphocytic leukemia may be helpful in identifying prognostically different subgroups of patients and planning therapeutic schedules.