Bone marrow involvement by non-Hodgkin's lymphoma: the clinical significance of morphologic discordance between the lymph node and bone marrow. Nebraska Lymphoma Study Group.

Bone marrow specimens from 317 patients with non-Hodgkin's lymphoma (NHL) obtained at initial staging were evaluated for the presence of lymphoma or benign lymphoid aggregates. Thirty-two percent (102 patients) had lymphoma in their bone marrow, and 9% had benign lymphoid aggregates. Bone marrow lymphoma was present in 39% of low-grade, 36% of intermediate-grade, and 18% of high-grade lymphomas. The bone marrow was involved in 25% of patients with diffuse large-cell or immunoblastic NHL (ie, diffuse histiocytic lymphoma of Rappaport). Bone marrow involvement did not affect survival of patients with low-grade NHL, but survival was significantly shorter (P = .03) for patients with intermediate- and high-grade NHL with bone marrow involvement. Bone marrow involvement was equally common in B-cell and T-cell NHL (31% v 32%). However, patients with T-cell NHL and bone marrow involvement had shorter survival than B-cell NHL with marrow involvement (P = .02) or T-cell NHL without marrow involvement (P = .05). A high incidence of morphologic discordance between lymph node and bone marrow was observed (ie, 40%), always with a more aggressive subtype in the lymph node than in the bone marrow. Presence of large-cell lymphoma in the bone marrow predicted for short survival. Survival for patients with small-cell lymphoma in their bone marrow did not differ significantly from patients with negative bone marrows. We conclude that bone marrow involvement in large-cell NHL, especially in those of T-cell origin, portends a poor prognosis. However, the subgroup of patients with an aggressive histologic subtype of NHL in a lymph node biopsy and small-cell NHL in the bone marrow do not have a poorer outlook than those without bone marrow involvement.