Totally implantable venous access devices are widely used in nutrition. The authors encountered a 10-year-old boy with implantation of the device at the age of 7 years. In the recent half-year, the device was not used except for regular heparin flushing. However, hydrothorax occurred when fluid therapy was required from the device during this admission. Thoracoscopic approach showed extravascular migration and intrapleural malposition of the catheter. Intrapleural migration of the extravascular portion of the catheter owing to irritation and pressure necrosis of the pleura and gradual shortening of intravascular portion of the catheter when the child grew up may be the pathogenesis of delayed extravascular migration of the catheter.