Prognostic significance of bone-marrow patterns in chronic lymphocytic leukaemia.

Bone-marrow biopsy has been performed in 63 cases of chronic lymphocytic leukaemia (CLL). Four different histological patterns were observed: (a) interstitial (lymphoid infiltration without displacement of fat cells) in 12 cases; (b) nodular (abnormal lymphoid nodules without interstitial infiltration) in 10 cases; (c) mixed (combination of the first two patterns) in 21 cases; and (d) diffuse (replacement of both haemopoietic and fat cells by lymphoid infiltration) in 20 cases. Statistical analysis of actuarial curves showed a significant difference of survival probability according to the bone marrow infiltration patterns. Thus, in patients with interstitial or nodular patterns the life expectancy is significantly longer than in those with mixed or diffuse patterns. furthermore, a significant degree of correlation between bone marrow infiltration patterns and different methods of clinical staging in CLL was apparent. The different bone marrow infiltration patterns in CLL probably reflects variations in the amount of lymphoid accumulation during the natural course of this disease. Because of its prognostic significance, bone marrow biopsy should have a place in CLL evaluation and staging.