Cytologically proved malignant pleural effusions: distribution of transudates and exudates.
OBJECTIVE
This study attempts to determine the distribution of transudates vs exudates in pathologically proved malignant pleural effusions and the necessity for cytologic studies in patients with a transudative effusion.


METHODS
A retrospective review of all cytologically positive malignant pleural effusions was performed at Duke University Medical Center over an 18-month period. All effusions were characterized as a transudate or an exudate based on standard criteria, including lactate dehydrogenase and protein values.


RESULTS
Ninety-eight patients with a mean age of 62 years were identified as having a cytologically positive malignant pleural effusion and blood chemistry values available to distinguish an exudate from transudate. Ninety-seven patients (99%, 95% confidence interval; 0.94 to 0.99) had criteria for an exudative effusion. One patient (1%) with diffuse metastatic lung cancer had a borderline transudate and was in congestive heart failure at the time of thoracentesis.


CONCLUSIONS
Cytologically positive pleural effusions for malignancy are almost always exudates. Cytologic evaluation for malignant cells of a transudative pleural effusion is not recommended.
Assi
Z
Z
Department of Internal Medicine, Duke University Medical Center, Durham, NC 27710, USA.
Caruso
J L
JL
Herndon
J
J
Patz
E F
EF
D003937:Diagnosis, Differential; D005122:Exudates and Transudates / Q000166:cytology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016066:Pleural Effusion, Malignant / Q000175:diagnosis / Q000453:epidemiology / Q000473:pathology*; D012189:Retrospective Studies