Application of quantifiable criteria in the Lukes and Collins classification of non-Hodgkin's lymphomas.

Measurements of nuclear size and differential counts among six lymphoma cell types were performed on H & E stained sections. In differential counting, the definition of cell types was based on nuclear shape, chromatin pattern, and nucleoli. In a pilot study comprising 93 patients we found actual nuclear size inadequate for use in lymphoma classification. This was due to: 1. great overlap among cytological types; 2. no independent prognostic value of mean nuclear area; 3. contradictory terminology; the large cleaved type belonging to the small cell category (mean nuclear area below 40 microns2), and the small non-cleaved type belonging to the large cell category (mean nuclear area above 40 microns2). Differential counting--requiring about 10 min--was an easy way to meet the need for a more objective evaluation of the cellular composition in non-Hodgkin's lymphomas. Quantifiable criteria based on differential counts were applicable in subclassification of three T-cell and seven B-cell types with an intraobserver reproducibility of 80%. More than 25% "large" cell types in a differential count implied an unfavourable prognosis. In test material, using a semi-morphometric classification, a correct prognostic category was obtained in 92% of 461 lymphomas and correct sub-classification obtained in 68%.