BackgroundAlthough chyle leakage may occur in the neck when the thoracic duct is damaged during cervical dissection, it is extremely rare for the chylothorax alone to leak chyle into the thoracic cavity. Case presentationWe report a case of bilateral chylothorax without chyle cervical leakage after left neck dissection, wherein partial left upper jaw resection and left radical neck dissection were performed in a 46-year-old woman who was diagnosed with left upper gingival cancer. The thoracic duct was ligated and cut during surgery and, although no obvious leakage of lymph was observed, dyspnea and cough reflex during deep inhalation were observed from the 3rd postoperative day. Approximately 600 mL of yellowish-white pleural effusion was aspirated during bilateral thoracentesis, and chylothorax was diagnosed based on clinical findings and biochemical analysis results. The patient was put on a low-fat diet on the 4th postoperative day, and a total of 3 neck drains were removed 8 days after the operation. ConclusionsPleural effusion disappeared on imaging examination 16 days after thoracentesis and 5 years and 6 months have passed since the operation. At this time, there has been no evidence of tumor recurrence, metastasis, or pleural effusion.