Postoperative chylothorax associated with lymphatic channels around the azygos arch after right upper lobectomy: a case report

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Background: Postoperative chylothorax is an uncommon complication of pulmonary resection and mediastinal lymph-node dissection. Anatomical variations of the thoracic duct and its tributaries are recognized, but their clinical relevance during right superior mediastinal lymphadenectomy may be difficult to appreciate. We report a case of postoperative chylothorax associated with an intraoperative finding of two lymphatic channels around the azygos arch after induction aumolertinib therapy. Case Description: A 71-year-old woman with epidermal growth factor receptor (EGFR) L858R-mutant lung adenocarcinoma and a solitary brain metastasis underwent craniotomy followed by 3 months of induction aumolertinib. After radiographic response, she underwent uniportal video-assisted thoracoscopic right upper lobectomy with systematic mediastinal lymph-node dissection. During dissection of stations 2R and 4R near the azygos arch, a translucent lymphatic channel was injured and milky fluid was observed. Further local exploration identified two separate lymphatic channels around the azygos arch; their complete course and relationship to the azygos vein could not be confirmed. The injured superior channel was ligated and clipped, whereas the inferior channel appeared intact and was not manipulated. Postoperatively, chylothorax developed, with pleural-fluid triglycerides of 524 mg/dL and drainage of 620 mL/day. Conservative treatment with nil per os, total parenteral nutrition, and intravenous somatostatin at 125 μg/hour by continuous infusion was initiated on postoperative day (POD) 1 and discontinued on POD 4. The chest tube was removed on POD 7, and no recurrent chylothorax or tumor progression was observed during 9 months of follow-up. Conclusions: This case describes an intraoperative observation of two lymphatic channels around the azygos arch during right superior mediastinal lymphadenectomy. Because no dedicated lymphatic imaging or formal anatomical confirmation was performed, the complete lymphatic course and anatomical classification of these channels remain uncertain. This observation is hypothesis-generating and should not be interpreted as definitive confirmation of a thoracic duct anomaly.