Clinical relevance of peripheral blood lymphocyte morphology and lymph node histology in chronic lymphocytic leukemia.

Peripheral blood lymphocyte (PBL) morphology and lymph node (LN) histology were evaluated in a prognostic study conducted in 247 patients with low-grade malignancies of B lymphocytes. The patients were classified according to total tumor mass (TTM) distribution pattern. A simple classification based on quantification of lymphoid cells that were morphologically different from small lymphocytes of peripheral blood was evaluated in the 166 leukemic patients. The lymph node histology was studied in 211 patients who had lymph node enlargement. The pattern of growth (pseudofollicular, diffuse, and tumorous), the proportion of distinct lymphocytes, and the degree of capsule infiltration were evaluated in 130 patients who showed leukemic involvement as well as enlargement of lymph nodes and/or spleen. Both PBL and LN morphologies correlate with the TTM distribution pattern and demonstrate a prognostic value that is independent of clinical characteristics. From the PBL morphology the LN morphology can be predicted. The prognostic power of the PBL morphology is lost after adjustment for the pattern of growth in LN and vice versa. A significant overlap between the PBL morphology and LN histology suggests some independence between the two variables and points to the possibility of biased classification if only one of the compartments is evaluated. Capsular infiltration is, however, a prognostic factor independent of both clinical and morphological characteristics. Morphological analysis in CLL is clinically relevant. Precise classification of patients requires analysis of both PBL and LN morphology to ensure comparability of patients admitted to clinical trials.