BONE-MARROW INVOLVEMENT IN ANAPLASTIC LARGE-CELL LYMPHOMA - IMMUNOHISTOCHEMICAL DETECTION OF MINIMAL DISEASE AND ITS PROGNOSTIC-SIGNIFICANCE

Bone marrow involvement by anaplastic large cell anaplastic large cell (ALC) lymphoma can be difficult to detect on routine morphologic exam ination alone, In a series of 42 patients with ALC lymphoma, the autho rs analyzed: (1) the usefulness of a limited panel of monoclonal antib odies directed against CD30 (Ber-H2, HRS4) and epithelial membrane ant igen (EMA) in detecting minimal bone marrow involvement on routinely p rocessed biopsy specimens; and (2) the prognostic significance of bone marrow involvement as detected on both morphologic and immunohistoche mical grounds. On conventional examination, 17% of the patients were f ound to have bone marrow involvement at diagnosis, However, after immu nohistochemical analysis, occult malignant cells were detected in 23% of the patients with negative bone marrow biopsy on routine histology, The low percentage of positive cases on routine morphologic examinati on compared to immunohistochemical examination was related to: (1) the scarcity of neoplastic cells which were scattered among hematopoietic cells; (2) the difficulty of distinguishing malignant cells from imma ture hematopoietic elements; and (3) the absence of alteration of the reticulin network, The authors observed a significant association betw een marrow infiltration and the presence of hematologic abnormalities (mostly anemia or cytopenias) at diagnosis, both in children and adult patients, More importantly, a significant lower survival was seen in patients with bone marrow involvement compared to those without bone m arrow involvement. Immunohistochemistry with anti-CD30 and anti-EMA an tibodies should be performed systematically in bone marrow biopsies fr om patients with ALC lymphoma to reliably identify the presence of bon e marrow involvement that appears to carry a poor prognosis.