Rolling stones in the pleural space: thoracoliths on CT, and a review of the literature

Abstract

Thoracolithiasis is a rare, benign condition, whereby a calcified or non-calcified loose body is present in the pleural space. We describe two cases of mobile thoracoliths, which were documented on several separate computed tomography (CT) examinations. One patient initially presented with abdominal pain and the other with lung cancer. The thoracoliths were incidental findings in the left pleural space and mediastinum on CT. On subsequent CT studies performed for follow-up, the thoracoliths moved within the left oblique fissure, an accessory fissure and mediastinum. The patients remained asymptomatic with regards to the thoracoliths. Thoracoliths are usually an incidental finding on imaging or at surgery, and do not require any treatment or intervention. They are seen predominantly on the left side and may relate to degenerated lipomas, old tuberculosis (old TB), phagocytosis of dust, or dropping of pleural or pericardial fat into the pleural space. This entity is rare, with only 20 cases reported to date in the literature. We review the literature on thoracolithiasis and discuss the aetiology and epidemiology. The differential diagnosis includes fibrin bodies, foreign body granulomas, and gallstone spillage into the pleural space following cholecystectomy.