Fig. 4

A case with invisible PAVM without pleural bulge. Although the diameter of the venous sac was 11 mm and relatively large, the PAVM, located 5.5 mm below the pleural surface, could not be identified immediately after insertion of the thoracoscope. The ipsilateral lung spontaneously contracted excessively while searching the PAVM, and the surgeon could identify the pleural bulge of PAVM approximately 40 min later