A Case of Distal Pancreatectomy for Pancreatic Metastasis of Thymic Atypical Carcinoid

Background: Thymic atypical carcinoid(AC) tends to have a more aggressive clinical course than typical carcinoid(TC). About 20%-30% of patients with thymic AC experience local recurrence or distant metastasis. Pancreatic metastasis of thymic AC is extremely infrequent. We experienced a case of pancreatic metastasis of thymic atypical carcinoid, in which a distal pancreatectomy was performed. Case presentation: A 50-year-old man underwent thoracoscopic resection of a mediastinal tumor in June 2009. The diagnosis was thymic AC. He also underwent an extended thymectomy in October 2011, thoracoscopic resection in October 2012, and tumor resection of the chest wall in March 2013 for recurrences. During follow up in April 2014, computed tomography (CT) revealed lymph node swelling on the ventral side of the brachiocephalic vein, around the left gastric vein, and on the left side of the celiac artery. Dynamic CT revealed a pancreatic tumor 10 mm in diameter with low enhancement. EUS-guided fine-needle aspiration (EUS-FNA) biopsy revealed the pancreatic tumor was compatible with metastasis of thymic AC. The patient underwent abdominal lymph node resection and distal pancreatectomy in June 2014. Because the lymph node on the ventral side of the branchiocephalic vein was judged as unresectable, 60-Gy radiation therapy was given in September 2014. Per pathological examination and immunohistochemistry, the final diagnosis was pancreatic metastasis of thymic AC. With several chemotherapy courses for recurrences, the patient has remained alive for eight years after the first surgery. Conclusion: AC metastasis to the pancreas is extremely rare. EUS-FNA is useful for diagnosis. Definitive determination of whether the treatment provides a survival benefit awaits further studies.