Visceral pleural invasion

Visceral pleural invasion is a feature that can be seen in lung cancers. It is defined as tumor extension beyond the elastic layer of the visceral pleura, and in some cases may result in a cancer crossing a fissure to invade an adjacent lobe of the lung. It is considered an aggressive sign and one of the most important adverse prognostic factors in non-small cell lung cancers ¹.

Pathology

Grading

There are three described levels of invasion (based on histology):

• PL0: represents tumor invading either the subpleural lung parenchyma or superficially the pleural connective tissue beneath the elastic layer
• PL1: refers to a tumor that invades beyond the elastic layer without being exposed on the pleural surface
• PL2: refers to a tumor that is exposed on the pleural surface, but it does not involve adjacent anatomic structures

Radiographic features

CT

The presence of type 2 pleural tags has been shown to have a moderate association with visceral pleural invasion ⁷.

Treatment and prognosis

According to one study, there was ~20% (range 10-30%) worse 5-year survival in tumors with visceral pleural invasion compared to those without visceral pleural invasion.

See also

• traversal of lung fissures