Liver resection for metastases of tracheal adenoid cystic carcinoma: Report of two cases

INTRODUCTION: Tracheal adenoid cystic carcinoma (ACC) is rare and accounts for <1% of all lung cancers. Although ACC is classified as a low-grade tumor, metastases are frequently identified in the late period. Extrapulmonary metastases are rare, and their resection has rarely been reported. PRESENTATION OF CASE: Case 1: A 77-year-old man underwent tracheal resection for ACC with postoperative radiation (60 Gy) 14 years before (at the age of 63). He underwent two subsequent pulmonary resections for metastases. Fourteen years after the first operation, he underwent extended right posterior segmentectomy with resection of segment IV and radiofrequency ablation for metastases of ACC to the liver. He was diagnosed with metastases to the kidney with peritoneal dissemination 4 years after the liver resection and died of pneumonia 2 years later. Case 2: A 53-year-old woman underwent a two-stage operation involving tracheal resection for ACC and partial resection of liver segments II and V for metastases of ACC to the liver. The tracheal margin was histopathologically positive. Postoperative radiation was performed, and she was tumor-free for 10 months after the liver resection. DISCUSSION: Complete resection of tracheal ACC provides better survival. Radiotherapy is also recommended. However, the optimal treatment for metastases of ACC is unclear, especially because liver resection for metastases of tracheal ACC is rarely reported. Our two cases of metastases of tracheal ACC were surgically managed with good outcomes. CONCLUSION: Liver resection for metastases of tracheal ACC may contribute to long survival.