Up to 25% of malignant pleural effusions can remain undiagnosed follow
ing history, physical examination, thoracentesis, and percutaneous clo
sed pleural biopsy. The next diagnostic procedure is often rigid thora
coscopy, an invasive procedure requiring an operating suite and usuall
y a postprocedure chest tube. We performed flexible fiberoptic pleuros
copy using a fiberoptic bronchoscope in conjunction with a closed pleu
ral biopsy on 12 patients with exudative pleural effusions that remain
ed undiagnosed despite extensive clinical evaluation. A sterile 4.8-mm
outside diameter flexible fiberoptic bronchoscope was placed into the
pleural space during the course of a routine closed pleural biopsy. P
neumothorax was induced to allow visualization, Brush or forceps biops
y specimens of suspicious parietal pleural lesions were taken. Eight p
leural spaces appeared smooth while four were diffusely studded on the
parietal surface. Of these four, three were proven to have diffuse pl
eural adenocarcinoma using this procedure; the fourth proved ultimatel
y to have pleural mesothelioma, On long-term follow-up (mean = 17.7 +/
- 11.4 months), no false-negative studies or unexpected morbidity was
noted. Flexible fiberoptic pleuroscopy may provide a diagnosis in exud
ative pleural effusions when other less invasive procedures fail to do
so and is well tolerated with minimal discomfort and risk.