Involvement of the bone marrow by non-Hodgkin's lymphomas: incidence, histology and pathologic correlations

The Lukes and Collins system of classification was applied to 151 cases of non-Hodgkin's lymphoma who had bone marrow biopsies taken immediately after histologic diagnosis. Incidence and histologic pattern of bone marrow involvement at the time of initial diagnosis were determined for each subtype of lymphoma. Thirty-three patients (21.8%) had bone marrow involvement. The frequency of bone marrow involvement was high for undefined and convoluted lymphocyte lymphomas (66.6%) and low to intermediate for follicular centre cell (20.3%) and small lymphocyte lymphomas (20.0%). Within the FCC lymphomas the non-cleaved cell type had a higher incidence of marrow involvement than the cleaved cell type (41.6% vs 8.9%). The follicular and diffuse histologic patterns in the diagnostic node did influence the incidence of marrow invasion in the non-cleaved cell type (75% vs 25%). A low incidence of marrow involvement was observed for the immunoblastic lymphomas (14.2%); evidence of marrow infiltration was never observed in patients with true histiocytic lymphomas.