A Case of Advanced Adenosquamous Carcinoma of Pancreas with Conversion Surgery after Chemoradiotherapy Followed by Systemic Chemotherapy

A man in his 60s with upper abdominal discomfort was referred to our hospital. CT scan revealed the 40 mm tumor in the body and tail of pancreas invading stomach wall. Solid soft tissue contact was also observed around celiac artery(CA)and common hepatic artery(CHA). EUS-FNA from pancreatic mass showed suspicion of adenosquamous carcinoma. We diagnosed it as pancreatic adenosquamous carcinoma, cT4N0M0, cStage Ⅲ. The patient received radiotherapy(46.8 Gy/26 Fr in total)combined with S-1. Although the primary lesion showed shrinkage, solid soft tissue around CA and CHA deteriorated. We judged the tumor unresectable, and the patient received systemic chemotherapy using gemcitabine(GEM). After 6 courses of GEM, solid soft tissue around CA and CHA almost disappeared. Based on these results, we performed distal pancreatectomy and partial gastrectomy 8 months after the initiation of the treatment. Pathological results showed adenosquamous carcinoma of the pancreas with Grade 2 response to the preoperative treatment. Although the tumor invaded into the gastric wall, R0 resection was achieved. The patient is alive with no recurrence a year and 4 months after the initiation of treatment and 8 months after resection.