[Recent views on the functional histological classification of malignant lymphomas]

The recent immunological classification of malignant lymphoma (ML) proposed by Lukes and Collins is examined. It is based on morphological changes linked to the dynamics of the reactive or secondary follicular clear centres. B-cells (follicular centre) are small or large and may cleft or not; they may proceed to macrophage or plasma cell types. T cells (around the follicles) are small and round, and have a convolute nucleus. ML types are distinguished by the predominance of one cell element, or by a mixture of cells from the maturative line of the follicular centre, i.e. T-cell (or convolute) lymphomas and B-cell (or follicular centre) lymphomas. Stem cells have none of these features. The classification was applied in a series of 32 non-Hodgkin and 24 Hodgkin ML's. Of the former, 23 were classed as B-cell types: 8 small and 5 large cleft cells; 7 small and 3 large non-cleft cells. The remainder were: 2 B-cell immunoblastic sarcomas, 3 histiocyte ML, 2 small lymphocyte ML, 1 ML with convolute lymphocytes, and 1 case with indeterminate cells ("stem cell lymphoma"). The 24 Hodgkin cases were classified in accordance with Rye's pattern (based on the work of Lukes et al.). It was noted that the numerical prevalence of convolute cells gradually fell, passing from lymphocyte dominance to lymphocyte depletion. At the same time, there was an increase in follicular centre cells and a diminution of plasma cell tending lymphocytes. The problems raised by this new immunological and morphogical classification of ML are discussed.