[Histological classification of malignant non-Hodgkin's lymphomas and patient survival: the Kiel classification versus the working formulation].

In 163 out of 251 histologically classified malignant Non-Hodgkin's lymphomas, a comparison was made of the patient survival with respect to both histological type and malignant grade according to the Kiel Classification (KC) and the three prognostic groups of the Working Formulation (WF). As expected, the survival rate of 94 low-grade malignant lymphoma cases (KC) was significantly better than that of 69 high-grade cases (p < 0.0001). Similar results were found both for 46 low grade cases (WF) in comparison to 50 high grade cases (p < 0.001) and for 67 intermediate grade cases (WF) compared with the 50 high grade cases (p < 0.05). The survival rates of low and intermediate grade cases (WF), however, showed no statistically significant difference. The low- and high-grade malignant lymphoma entities of KC, which together constitute the intermediate grade of WF, differed significantly with respect to patient survival (p < 0.05). Therefore, it appears that an intermediate grade is not essential in the KC.