Distinction between bronchioloalveolar carcinoma and hyperplastic pulmonary proliferations: a cytologic and morphometric analysis.

The objectives of this study were to identify key cytologic features for the morphologic differentiation of bronchioloalveolar carcinoma from reactive pulmonary proliferations, and to determine if morphometry of the cytologic specimens could provide additional data to distinguish the two processes. We analyzed 15 morphologic criteria in pulmonary cytologic specimens from 17 histologically proven cases of bronchioloalveolar carcinoma and 13 cases with reactive cellular changes and compared the findings using univariate analysis. This revealed four statistically significant features more commonly associated with bronchioloalveolar carcinoma: (i) predominance of two- and three-dimensional tissue fragments, (ii) tenacious intercytoplasmic connections between cells, (iii) intranuclear cytoplasmic inclusions, and (iv) paucity of multinucleated cellular forms. Morphometric measurement revealed significant differences between the mean of the nuclear area of benign reactive cells and that of the malignant cells. The utilization of these criteria is helpful to diagnose bronchioloalveolar carcinoma and to distinguish it from reactive pulmonary processes.