Data Last Updated: June 9, 2025

Pleural Effusion

Description

Pleural effusion is the accumulation of fluid between the parietal pleura (the pleura covering the chest wall and diaphragm) and the visceral pleura (the pleura covering the lungs). Pleural effusion is the accumulation of fluid between the two layers of pleura: visceral (covering the lungs) and parietal (lining the chest wall and covering the diaphragm). Pleural effusion is a symptom of mesothelioma that increases the Summary Stage from local or regional direct extension to distant involvement.

Notes

**Note:** **Definition of pleural effusion** * One of the most common symptoms of mesothelioma is a pleural effusion, or an accumulation of fluid between the parietal pleura (the pleura covering the chest wall and diaphragm) and the visceral pleura (the pleura covering the lungs). * Record the absence or presence of pleural effusion and specifically, if present, whether the pleural effusion is non-malignant, malignant, atypical or NOS.
Code Description
0 Pleural effusion not identified/not present
1 Pleural effusion present, non-malignant (negative)
2 Pleural effusion present, malignant (positive)
Physician states pleural effusion is malignant in the absence of positive cytology
3 Pleural effusion, atypical/atypical mesothelial cells
4 Pleural effusion, NOS
8 Not applicable: Information not collected for this case
(If this item is required by your standard setter, use of code 8 will result in an edit error.)
9 Not documented in medical record
Pleural effusion not assessed or unknown if assessed