Abstract
A 58-year-old female was diagnosed as having dilatation of the common bile duct on abdominal ultrasound. MRCP and upper abdominal CT showed no abnormal findings, but blood chemistry findings revealed that the CA19-9 was 160 U/ml. Because the CA19-9 levels became higher and higher, we performed CT again. It showed a presacral tumor shadow. A barium enema demonstrated the posterior wall of rectum pressed outwards. Endoscopic ultrasonography of the rectum demonstrated a polycystic tumor, which we suspected as being a submucosal tumor of the posterior wall of the rectum. The tumor was resected by a transsacral operation and lower rectum circle resection. The pathological diagnosis was a tailgut cyst. After the operation, the levels of CA19-9 normalized.
