Frozen section of pleural biopsies at medical thoracoscopy assists in correctly identifying benign disease.

OBJECTIVES: Medical thoracoscopy and thoracoscopic talc poudrage (TTP) are accepted procedures in the management of pleural effusions. The relative merits of TTP compared with pleurodesis via intercostal catheter (ICC) continue to be debated. However, of the two procedures, only medical thoracoscopy allows both tissue diagnosis and pleurodesis to be achieved reliably in one procedure. The aim of this study was to assess the feasibility and accuracy of using frozen section analysis of samples taken during medical thoracoscopy to assist the thoracoscopist's decision to complete the procedure with a TTP.

METHODOLOGY: Twenty patients with undiagnosed pleural effusions after at least one diagnostic pleurocentesis underwent medical thoracoscopy and biopsy.

RESULTS: Frozen sections were easily performed within the timeframe of medical thoracoscopy. The final diagnosis based on paraffin sections was malignant in 10 cases and benign in 10 cases. Frozen section at the time of thoracoscopy (before TTP) correctly identified nine of 10 cases as being benign and six of 10 cases as malignant. In the malignant group, reasons for incorrect identification as benign were sampling from superficial benign adipose tissue overlying the malignant deposits, difficult access to the most involved parts of the pleura and intense cellular infiltrate initially thought to be benign.

CONCLUSION: Frozen sections taken during medical thoracoscopy have the potential to facilitate decision-making prior to pleurodesis, particularly for accurate identification of benign histology on thoracoscopic pleural biopsies, in order that pleurodesis is not performed unnecessarily.