[Chronic lymphatic leukemia. Immunophenotyping as an aid to correct diagnosis]

The purpose of the study was to examine the validity of the primary diagnosis in chronic lymphocytic leukemia based on clinical and morphological criteria, and to examine the role of immune phenotyping for correct diagnosis in an unselected population-based group of patients. Over a 2-year period leukemic cells from 222 of 235 patients in Norway with a recent clinical diagnosis of chronic lymphocytic leukemia (CLL) were immune phenotyped in order to find cases erroneously diagnosed as CLL. Median age was 72.5 years, and the ratio of men to women was 1.47. At the time of diagnosis, 77% of the patients were in Binet stage A and 23% in stage B or C. Immune phenotyping, in some patients followed by lymph node or bone marrow biopsy, showed a different diagnosis in 11 (5%) of 222 patients: prolymphocytic leukemia, four patients (three B-cell and one T-cell); morbus Waldenstrøm, one patient; T-cell CLL, one patient; hairy cell leukemia, one patient; mycosis fungoides, one patient; mantle cell lymphoma, one patient; monocytoid B-cell lymphoma, one patient and immunoblastic lymphoma one patient. In eight of these 11 patients, the clinical features or morphology, or both, were atypical for CLL, but this was not recognized at the time of diagnosis. Thus, immune phenotyping is valuable for correct diagnosis in a small subgroup of patients with chronic B- or T-cell leukemia, and it is essential in patients with modest lymphocytosis (lymphocytes < 10. 10(9)/1).