Can peripheral T‐Cell lymphomas be morphologically subclassified? A morphometric approach to 21 cases

Morphometric analysis of nuclear sizes and shapes was carried out on semithin sections of lymph node for 21 patients suffering from non‐Hodgkin's peripheral T‐cell malignant lymphoma (ML) (excluding mycosis and Sézary syndrome). Twenty cases of B‐cell ML and three cases of Sézary syndrome with massive lymph node infiltration were also studied as references. Wright and Isaacson's recent proposals were applied to classify the peripheral T‐cell MLs into monomorphic medium‐cell ML (eight cases), pleomorphic ML (nine cases), and monomorphic large‐cell ML (four cases). These three classes were readily distinguishable by morphometric analysis of nuclear sizes. Nuclear areas and their coefficients of variation were higher in pleomorphic MLs than in monomorphic medium‐cell MLs (p < 0.01). Large‐cell monomorphic MLs were set apart by the histograms of their nuclear sizes. The mitoses were evaluated on histological sections and found to be more numerous in pleomorphic ML than in monomorphic medium‐cell ML (p < 0.05). Nuclear irregularity in the 21 cases of peripheral T‐cell ML was lower than in Sézary cells. Morphometry clearly demonstrates the morphological distinctiveness of the subclasses of peripheral T‐cell ML. Their biological significance has yet to be determined.