Pleural effusion is the abnormal excessive accumulation of fluid in the pleural cavity. Pleural effusion per se is not a diagnosis but is indicative of an underlying pathology.  It can occur by itself or can be the result of surrounding parenchymal diseases like infection, malignancy, or inflammatory conditions. Pleural effusion is one of the major causes of pulmonary mortality and morbidity. Patients with pleural effusions often present without many symptoms. Symptoms associated are pleuritic chest pain, cough, and shortness of breath. In addition, the patient will have symptoms related to the underlying cause.

 In India currently, the most common cause of pleural effusion is tuberculosis (59-65%) followed by malignancy (22-25%). Parapneumonic effusion and cardiac failure constitute about 20% of total cases. However, a small portion of cases of pleural effusion remained undiagnosed even after pleural fluid examination and cell block.

Pleural biopsy via thoracoscopy is one of the most important methods of diagnosing pleural disorders. Forceps biopsies have been regularly used with semi-rigid thoracoscopy with good yield and safety. Cryo-pleural biopsy has been recently employed with semi-rigid thoracoscopy and many studies have been performed highlighting the safety and diagnostic yield.

At present only 1 RCT has been performed comparing diagnostic yield of thoracoscopic cryo versus forceps biopsy.