Objective Thoracoscopic Criteria in Differentiation between Benign and Malignant Pleural Effusions

Abstract

<b><i>Background:</i></b> Thoracoscopy is the “gold standard” diagnostic modality for investigation of suspected pleural malignancy. It is postulated that meticulous assessment of the pleural cavity may be adequate to indicate malignancy through the macroscopic findings of nodules, pleural thickening, and lymphangitis. We attempted to critically assess this practice, by precisely defining objective macroscopic criteria which might differentiate benign from malignant pleural diseases according to intrapleural pattern and anatomical location, and thereby to explore the predilection of abnormalities to specific sites on pleural surfaces. <b><i>Methods:</i></b> A structured review of recorded video footage from medical thoracoscopy procedures in 96 patients was conducted by 2 independent assessors. Abnormalities were scored on agreed, objective criteria for the presence of nodules, lymphangitis and inflammation on each of the costoparietal, visceral and diaphragmatic surfaces. The costoparietal pleura was divided into 6 levels (apical, middle, and inferior surfaces of the lateral and posterior parietal pleura). The anterior surface of the costoparietal pleura was excluded from analysis after interim review as this surface was rarely seen. <b><i>Results:</i></b> In the benign group, inflammation was the predominant finding in 65% (<i>n</i> = 33; costoparietal), 44% (<i>n</i> = 21; visceral), and 42% (<i>n</i> = 15; diaphragmatic). Nodules were detected in 24% (<i>n</i> = 12; costoparietal), 8% (<i>n</i> = 4; visceral), and 8% (<i>n</i> = 3; diaphragmatic). The most affected surfaces with inflammation were the middle lateral (60%) and the inferior lateral (57.8%) parts of the costoparietal pleura. In the malignant group, nodules were the predominant finding according to surface in 73% (<i>n</i> = 33; costoparietal), 32% (<i>n</i> = 13; visceral) and 48% (<i>n</i> = 17; diaphragmatic). Inflammation was detected in 44% (<i>n</i> = 20; costoparietal), 25% (<i>n</i> = 10; visceral), and 29% (<i>n</i> = 10; diaphragmatic). The most affected surfaces with nodules were the middle lateral (67.4%) and inferior lateral (66.7%) costoparietal pleural surfaces. <b><i>Conclusion:</i></b> This is the first detailed, anatomical description of abnormalities in the pleural space during thoracoscopy. While nodules were the predominant pattern in malignant pleural effusion, they were detected in 24% of benign diagnoses. Detection of nodules in >1 area of the costoparietal pleura was in favor of a malignant diagnosis. Inflammation was the predominant pattern in benign pleural effusion. Our results suggest that macroscopic nodules in malignant diagnoses have a predilection for the middle and inferior surfaces of the lateral costoparietal pleura.

Inflammation of the Pleural Cavity: A Review on Pathogenesis, Diagnosis and Implications in Tumor Pathophysiology

“…However, while nodules were the predominant pattern in malignant pleural disease, they were also detected in 24% of benign etiologies [80]. In a study of 100 consecutive pleural biopsies with benign diagnosis (no cancer), the predominant macroscopic pattern was inflammatory in 40% of cases, fibrinous in 14%, septated in 8%, fibrous in 6%, hemorrhagic in 2%, and pleural plaques in 2% [72].…”

“…The first possibility is associated to the frequently complicated macroscopic appearance of the pleural cavity making it difficult to select the biopsy sites. A recent study describing the macroscopic features of the pleura during thoracoscopy showed that pleural disease of benign etiology presented principally an inflammatory macroscopic aspect with the most affected areas being the middle and inferior lateral costoparietal pleura, while in the malignant group, nodules were the predominant finding actually affecting the same localization [80].…”

Local Anaesthetic Thoracoscopy for Pleural Effusion—A Narrative Review

“…Furthermore, Carlo Forlanini, in Pavia, Italy, used a similar method in 1882 to create an artificial pneumothorax and induce lung collapse, a treatment that was thought to be beneficial in pulmonary tuberculosis [ 2 ]. Direct visualisation of the pleura enables biopsies to be taken from the parietal pleura and pleural-based abnormalities such as nodules, increasing diagnostic yield, particularly in malignancy [ 3 ]. At the same time, any fluid can be drained offering symptomatic relief to the patient and measures such as talc pleurodesis or indwelling drains can be respectively performed or inserted for fluid management [ 4 ].…”