Nonspecific pleuritis

Nonspecific pleuritis (NSP) is inflammation or fibrosis of the pleura that is discovered on biopsy and cannot be attributed to a specific benign or malignant aetiology. It is diagnosed on biopsy in ⩽30% of cases of exudative pleuritis after thoracoscopy. While there is debate over the timing of follow-up, at 21 months roughly 14% of those with NSP develop malignancy within the pleura (mostly mesothelioma) and most of these patients have clinical characteristics suggesting an active process is developing. This chapter will review the diagnosis and incidence of NSP, appropriate clinical surveillance, when it is clinically indicated to repeat a biopsy, and who to refer for surgical biopsy.