The diagnosis and significance of visceral pleural invasion in lung carcinoma. Histologic predictors and the role of elastic stains.

Invasion of the visceral pleura is an important component of lung carcinoma staging, and in some studies is an independent prognostic indicator. Evaluation of invasion by H&E may be indeterminate. Elastic stains can be helpful but are performed rarely. We reviewed all lung carcinoma resections from 1993 for 13 histologic features potentially predictive of pleural invasion. Of57 resections, 20 were indeterminate by H&E. Verhoeff-Van Gieson (VVG) stain revealed invasion in 8 cases, increasing the pathologic stage in 1. VVG stain was negative in 12 cases, 2 of which had been falsely reported as positive, decreasing the stage in 1. Angiolymphatic invasion and single-cell spread were significant predictors of invasion. Absence of both or the presence of intervening aerated parenchyma predicted lack of involvement in all cases. Elastic stains can provide prognostically important information, changing the pathologic stage in 4% of lung carcinoma resections overall and in 10% of cases indeterminate by H&E for pleural invasion.