Prognostic significance of differential cell counts in non-Hodgkin's lymphomas.

The use of differential counting on H & E stained sections is proposed as a simple means to define low grade malignant and high grade malignant cytologic categories in non-Hodgkin's lymphomas. Differential counts were performed in lymphoma biopsies from 616 cases. In each biopsy we counted 100 lymphoma cells and classified each cell as belonging to a "small", "medium-sized", or "large" cell type. The results indicate the presence of two prognostically distinct cytologic categories: a low grade and a high grade malignant. Lymphomas with less than 10% "large" cells represented low grade malignant cytology. Included in this category were also the, mainly follicular, lymphomas with more then 70% "medium-sized" cells (up to about 25% "large" cells). In addition to the cytologic category, the architectural pattern is of major prognostic importance. We recommend the use of three prognostic categories in non-Hodgkin's lymphomas: I) Favourable architecture + favourable cytology. II) Unfavourable architecture + favourable cytology. III) Unfavourable cytology.