Pleural fluid cytological yield and visceral pleural invasion in patients with epithelioid malignant pleural mesothelioma.
BACKGROUND
Malignant pleural mesothelioma (MPM) is an aggressive malignancy arising from mesothelial cells lining the pleura. Most commonly, it presents as a unilateral pleural effusion. MPM usually develops on the parietal pleural surface and later spreads to the visceral pleura. Visceral pleural involvement entails a more advanced disease stage and is therefore an important prognostic factor. Pleural fluid (PF) cytology is often the first diagnostic test, but the sensitivity in the literature varies from 4 to 77%. However, no data are available for the diagnostic yield of cytological PF analysis with regard to the visceral pleural involvement. The aim of this study is to assess whether PF cytological yield is related to the extent and pattern of visceral pleural invasion, as assessed by thoracoscopy.


METHODS
Medical records of all patients who underwent thoracoscopy for suspicion of malignant pleural effusion from two hospitals were reviewed. Patients were selected if they initially underwent a diagnostic thoracentesis before thoracoscopy, if visceral pleural appearance during thoracoscopy was clearly documented, and MPM confirmed on pleural tissue biopsy.


RESULTS
Seventy-five patients were selected. Forty-five patients had a positive PF cytology on thoracentesis, while 30 had a negative PF cytology. Thoracoscopy showed parietal pleural invasion in all subjects. Interestingly, 82% of patients with positive PF cytology on thoracentesis had visceral pleural involvement, whereas only 30% of those with negative PF cytology had visceral pleural invasion. The pattern of visceral pleural invasion consisted of pleural masses, nodules, or pleural thickening. A multivariate regression identified visceral pleural invasion (p < 0.001) as the only independent factor predicting the positivity of cytology on pleural effusion.


CONCLUSIONS
In epithelioid MPM, PF cytological yield was significantly higher in patients with visceral pleural invasion assessed by thoracoscopy. Positive PF cytology is associated with a more advanced disease.
Divisione di Pneumologia, Spedali Civili, Brescia, Italy. valentina.pinelli@gmail.com
Valentina
V
Pinelli
Sophie
S
Laroumagne
Lama
L
Sakr
Gian Pietro
GP
Marchetti
Gian Franco
GF
Tassi
Philippe
P
Astoul
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003581:Cytodiagnosis; D005122:Exudates and Transudates; D005260:Female; D006801:Humans; D008297:Male; D008499:Medical Records; D008654:Mesothelioma / Q000473:pathology*; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009375:Neoplasms, Glandular and Epithelial / Q000473:pathology*; D010994:Pleura / Q000473:pathology*; D016066:Pleural Effusion, Malignant / Q000473:pathology*; D011379:Prognosis; D013906:Thoracoscopy