A method for the quantification of cellular composition in lymphoma biopsies.

Abstract

A method for the classification and quantification of lymphoma cells in non-Hodgkin lymphomas is described. Lymphoma-cell types were defined and used in differential counts of haematoxylin and eosine stained paraffin-embedded sections. The following cell types were distinguished: small lymphoid cells (small lymphocytes and small plasma cells), medium-sized lymphoid cells (round, cleaved and cerebriform lymphocytes, and medium-sized plasma cells), and large lymphoid cells (lymphoblastic, round triple-nucleolated, and pleomorphic types). The intra-observer agreement in the classification of cell types was 43-85%. The agreement in distinguishing small, medium-sized, and large lymphoid cells was 85-92%. In differential counts in contrast to conventional histologic classification all cellular profiles were classified regardless of possible tangential cutting. 92% of the cellular profiles at different sectional planes of the same cells were consistently classified, indicating that tangential cutting of cells only influenced the differential counts to a minor degree. By the quantification of cellular composition in multiple, randomly selected areas, classified as representative at low power magnification, only small intra-lymphoma variations were observed in contrast to marked inter-lymphoma variations. The high reproducibility of lymphoma-cell types in combination with the small intra-lymphoma variation makes the quantifiable method suitable in the histological evaluation of non-Hodgkin lymphomas.