Diagnostic and differential diagnostic criteria of lymphoid neoplasms in bone marrow trephine biopsies: a study of 87 cases.

The aim of this study is to present the diagnostic and differential diagnostic criteria of the bone marrow specimen involved by lymphomas based on the histomorphological immunophenotype features and clonality of the tumor cells, patterns of lymphoproliferation and diagnostic pitfalls. BMB material obtained from the right posterior iliac crest was represented from 87 untreated and treated patients with BM involving malignant lymphoma, stained with Hematoxylin-Eosin, Giemsa, Periodic Acid Schiff and Gömöri's Silver. In order to perform immunohistochemistry examination we used a large antibody panel. B-cell clonality was determined in six cases. We found eight reactive lymphoproliferative responses and 79 lymphoid neoplasms of which 45 were diagnosed as de novo lymphoma, the rest of 34 samples being examined for staging. The predominant lymphoma was CLL (30 cases), over followed by DLBCL (18 cases). The most frequent patterns of involvement were the interstitial (29%) and mixed (15%) ones. In eight cases, we found reactive lymphoid aggregates. The B-cell clonality test showed four monoclonal, one oligoclonal and one polyclonal diseases form. Diagnosis of lymphoma versus reactive aggregate has been based on the combination of a lot of antibodies and involvement pattern. Although investigation of gene rearrangement was necessary for the establishment of the correct diagnosis in only 6.9% of cases, it should be emphasized that it is of great importance in disease monitoring.