Percutaneous Radiofrequency Ablation (RFA) is a safe, effective and well-established treatment of hepatocellular carcinoma (HCC) or hepatic metastases. Pleural effusion has been reported in 0.2%–2.7% cases as a complication of RFA. However, chylothorax has never been reported as a complication. We report the first two cases of chylothorax after RFA.
Case 1: A 50 year old male with hepatitis C, alcoholic cirrhosis and HCC in the posterior aspect of right lobe of liver received RFA. Because of the location of HCC against inferior vena cava, an ablation electrode was entered through the right pleural space. He was admitted with a chest tube for pneumothorax and was discharged after four days. Ten days later he presented with respiratory distress and a massive right-sided pleural effusion. Two liters of cloudy, chylous pleural fluid (triglycerides 155mg/dL) were removed (Table 1Case 1At presentationAfter three weeksPleural FluidSerumPleural FluidSerumpH7.40LDH90 IU/L293 IU/l56 IU/L359 IU/lTotal Protien0.4 g/dL5.9 g/dL0.4 g/dL5.4 g/dLTriglycerides155 mg/dL43 mg/dL61 mg/dL96 mg/dLCholesterol6 mg/dL113 mg/dL6 mg/dL113 mg/dLCase 2At presentationAfter four weeksPleural FluidSerumPleural FluidSerumpH7.60LDH84 IU/L275 IU/L26 IU/L262 IU/LTotal Protien1.1 g/dL7.5 g/dL0.3 g/dL6.5 g/dLTriglycerides292 mg/dL61 mg/dL82 mg/dL56 mg/dLCholesterol6 mg/dL113 mg/dL8 mg/dL109 mg/dL). No ascites was found by ultrasound. He required three more large volume thoracenteses. Three weeks later his pleural fluid triglyceride level had decreased (Table 1). A thoracoscopy with talc pleurodesis was done after eight weeks for continued accumulation of serous pleural effusion. Case 2: A 60 year old male with hepatitis C, alcoholic cirrhosis and HCC was treated with RFA. Three semi-flexible 25cm ablation electrodes were entered through the right pleural space. The tumor was ablated at 110 degree Fahrenheit for 12 minutes at 150 watts. He was admitted with chest tube for pneumothorax and was discharged after five days. Twenty days later he presented with dyspnea and a massive new right sided pleural effusion. Two liters of cloudy, chylous fluid (Table 1) were removed with symptomatic improvement. Abdominal ultrasound did not reveal ascites. Four weeks later his pleural fluid triglyceride was decreased(Table 1). He continued to have frequent large volume thoracenteses. No defect was seen in the visible portion of the diaphragm during thoracoscopy and talc pleurodesis was done.
Transudative pleural effusion with respiratory distress after RFA has been described. We believe no direct trauma to thoracic duct (TD) or its immediate tributaries was caused by RFA as the path of ablation electrode was on the lateral side of the liver. Also, the protein content of the fluid was much lower than 3mg/ml as expected in chylothorax from TD disruption. Transudative chylothorax in cirrhotic patients is postulated to be from translocation of ascitic fluid to the pleural space. None of our patients had ascites. However, hepatic hydrothorax has been reported in absence of ascites and it is possible that chylothorax was of abdominal origin and entered the pleural space through the diaphragmatic defects created during RFA even in the absence of clinical ascites. During removal of the catheter the tract was cauterized and this may have contributed to diaphrgmatic defect. Although full inspection of the diaphragm could not be done during thoracoscopy, no defect was seen in the visible area. Chylothorax may result from disruption of the lymphatic collaterals of the thoracic duct. Heat generated during RFA is thought to cause pleural effusion if the superior aspect of the liver such as segments 7 or 8 near the dome of the diaphragm are involved. This is a possible explanation of the delayed appearance of chylothorax and its transformation into a hydrothorax.
Delayed transient chylothorax may develop after RFA of HCC. Disruption of collateral lymphatic in pleural cavity, diaphragm or intercostal area during thermal ablation may be responsible. A chylothorax is rare but may occur when the tumor is accessed through pleural space or if the tumors are located near the dome of the diaphragm.
S.U. Islam, None.