Histopathology of large cell lymphomas (Report no 9)

The purpose of this communication is to discuss and illustrate the different microscopical features of members of this important group of large cell lymphomas and to give some indication of prognosis in relation to histopathology. The diffuse large cell lymphoma is a heterogeneous category of tumour previously designated reticulum cell sarcoma in traditional classifications, and 'histiocytic' by Rappaport. The majority are, however, large lymphoid cell tumours which on the basis of their light microscopic anatomy may be subdivided into those of follicle centre (B-lymphocytic) origin, immunoblastic type of either B- or T-lymphocytic origin, and 'undifferentiated'--meaning that although acceptable as lymphoid in nature at light microscopical level there are no further distinguishing features. Plasma cell (extramedullary) lymphomas are separately categorised. A smaller but significant minority group are of histiocytic (mononuclear phagocytic) derivation. Rarely tumours are encountered involving peripheral lymphoreticular tissue but which are derived from other cell types indigenous to the lymphoreticular and mononuclear and phagocytic system.