What is the Clinical Significance of Transudative Malignant Pleural Effusion?

Abstract

Background:A few reports of transudative malignant effusion on a small number of patients have suggested the need to perform routine cytologic examination in all cases of transudative pleural effusion, whether encountered for malignancy or not. The purpose of this study was to investigate whether cytologic examination should be performed in all cases of transudative pleural effusion for the diagnosis of malignancy.Methods:We performed a retrospective study of 229 consecutive patients with malignant pleural effusion, proven either cytologically or with biopsy. In patients with transudative pleural effusion, we reviewed medical records, results of transthoracic echocardiography, fiberoptic bronchoscopy, chest X-ray, chest CT scan, and ultrasonogram of the abdomen. These data were examined with particular attention to identifying whether or not the malignancy was suggested on chest X-ray, examining the involvement of the superior vena cava, great vessels, and lymph nodes, determining the presence of pericardial effusion, and observing the endobronchial obstruction.Results:Transudative malignant pleural effusion was observed in seven (3.1%) of the 229 patients, and was caused either by the malignancy itself (6 patients) or by coexisting cardiac diseases (1 patient). All the patients showed evidence suggesting the presence of malignancy at the time of initial thoracentesis, which facilitated the decision of most clinicians on whether to perform cytologic examination for the diagnosis of malignancy.Conclusion:Therefore, in all cases of transudative pleaural effusion, no clinical implications indicating malignancy were found on cytologic examination.

The Role of Vascular Endothelial Growth Factor in the Pathogenesis, Diagnosis and Treatment of Malignant Pleural Effusion

“…These include lymphocytic predominance with lymphocytes representing 50-70% of nucleated cells, >10% eosinophils, the presence of erythrocytes, pH < 7.3 and glucose < 60 mg/dL [2, 86]. While the majority of MPEs are exudative effusions, it should be noted that 3-10% are transudates, according to Light’s criteria [87-89]. However, definitive diagnosis of MPE requires the identification of malignant cells within the fluid or positive pleural biopsy, as the aforementioned features are relatively non-specific [2].…”

Recent Advances in the Diagnosis and Management of Malignant Pleural Effusions

“…It should be noted that 3% to 10% of MPEs are transudates. 46,47 Malignant transudative effusions result from the imperfect application of diagnostic rules that categorize pleural effusions or comorbid conditions associated with transudates, such as hypoalbuminemia, cirrhosis with ascites, or chronic heart failure. LIGHT CRITERIA Pleural effusions are most commonly categorized as transudates or exudates by the diagnostic rule termed Light criteria ( Table 1).…”

Diagnosis and management of malignant pleural effusions

“…The presence of an unexplained exudate suggests the possibility of a MPE, although exudates may be caused by non‐neoplastic inflammatory conditions. Conversely, because 3% to 10% of MPE are transudative in nature, the absence of exudative characteristics does not exclude the possibility of either a MPE or a paraneoplastic effusion 46,47 . Transudative effusions may occur as a result of the inherent misclassification rates of tests used to categorize pleural effusions or the existence of comorbid conditions commonly associated with transudates, such as congestive heart failure, trapped lung or hypoalbuminaemia.…”