Chronic Lymphocytic Leukemia (B-CLL) and Immunocytoma (LP-IC): Clinical and Prognostic Relevance of this Distinction

The Kiel classification of non-Hodgkin lymphomas (NHL) has established chronic lymphocytic leukemia (B-CLL) and immunocytoma (LP-IC) as separate entities of low-grade malignant NHL by morphological and immunohistochemical criteria. The clinical and prognostic relevance of this discrimination was evaluated in a prospective multicenter observation study by the Kiel Lymphoma Study Group. From 1975 to 1980, 430 previously untreated patients with B-CLL (n = 217) and LP-IC (n = 213)a were recruited and followed for up to 14 years. While the age and sex distribution and the incidence of clinical stages were quite similar in both entities major differences between initial manifestations in B-CLL and LP-IC became evident, e.g. in the incidence of bone marrow infiltration (99.5 vs. 86%), peripheral blood lymphocytosis (99.5 vs. 60%), or monoclonal gammopathy (1 vs. 30%). A strictly localized tumor (Ann Arbor stage I/IE) was seen in only 1.5% of the LP-IC patients who were successfully treated by local radiotherapy. In all other patients an expectative-palliative treatment concept was pursued. Long-term survival data analysis revealed significant differences between B-CLL and LP-IC and identified the pseudofollicular in B-CLL and the lymphoplasmacytic in LP-IC as the most favorable histological subtypes. The discriminative prognostic potential of clinical stage (Rai or Binet classification) for B-CLL and LP-IC varied and the pattern of prognostic risk factors obtained by multivariate analysis was not identical. Thus, the morphological distinction between B-CLL and LP-IC correlates with characteristic differences between these entities both in their initial clinical presentation and long-term prognosis.