Large cell lymphomas. I. Differential diagnosis of centroblastic and B-immunoblastic subtypes by morphometry on histologic preparations.

Thirty-three large cell lymphomas, 18 centroblastic or large noncleaved follicle center cell lymphomas and 15 B-immunoblastic lymphomas, diagnosed by morphology and marker studies, were studied with morphometry. The following parameters were studied: nuclear and nucleolar area, nuclear shape, cytoplasm-to-nucleus ratio, number of nucleoli per nuclear cross section, location of the nucleolus within the nucleus as expressed by the relative nucleolar eccentricity (rNE), and the percentage of morphometrically defined immunoblasts. Mean values and standard deviations (SDs) were calculated and statistically analyzed. The two groups differed significantly in their nucleolar area (mean and SD), cytoplasm-to-nucleus ratio (mean), number of nucleoli per nuclear cross section (mean and SD), rNE (mean), and percentage of immunoblasts. Using nonlinear discriminant analysis, the possibility of classifying individual cases with the studied parameters was investigated. Twenty-nine cases were reliably classified (88%); three were classified correctly, but with less than a 95% certainty, and 1 case was misclassified. The results indicate a spectrum ranging from centroblastic to B-immunoblastic lymphoma. Transition forms occur and can be accurately defined with morphometry.