Pancreatic mucinous cyst adenocarcinoma producing CA 19-9. A case report.

CONTEXT We herein present a rare case of a mucinous cystic neoplasm of the pancreas producing CA 19-9 and the clinical implications are discussed. CASE REPORT A 35-year-old woman with no history of abdominal surgery presented at Saisei Kai Sendai Hospital with an upper abdominal distention. Abdominal CT showed a large lobulated cystic tumor at the pancreatic tail. No distant metastases were identified. The preoperative serum CA 19-9 level was 6,200 U/mL (reference range: 0-37 U/mL). A mucinous cystic neoplasm of the pancreas was diagnosed and elective surgery was performed. On laparotomy, a round tumor 15 cm in diameter was encountered in the upper left abdomen. No invasion of neighboring organs or the portal vein was apparent. The entire tumor was curatively resected with a distal pancreatectomy. The final histopathological analysis revealed mucinous cystadenocarcinoma with no invasive component. Immunohistochemical staining disclosed CA 19-9 expression within the tumor cells. The CA 19-9 level normalized rapidly postoperatively and, although a minor pancreatic fistula occurred, this was resolved conservatively. She was discharged on the 45th postoperative day with no sign of tumor relapse; her CA 19-9 level was within the normal range 20 months postoperatively. CONCLUSION We present this rare case of a mucinous cystic neoplasm producing CA 19-9 and discuss the relevant literature. The CA 19-9 production in this tumor does not appear to be directly correlated to aggressive clinical behavior.