Abstract
We report a case of a tailgut cyst that was strongly suspected based on preoperative imaging findings. The patient was a pregnant woman in her 30s ; transvaginal ultrasonography done at 33 weeks 4 days of pregnancy showed a cystic lesion, 6.0×5.1cm, in the pelvis. The patient was asymptomatic, but an elastic soft mass in the posterior wall of the rectum was noted during the rectal examination. Pelvic CT and MRI examinations were performed after delivery ; a cystic mass with clear borders in the presacral space was noted. The tumor was completely excised via a trans-sacral approach with a coccyx resection for the tailgut cyst that was suspected based on preoperative imaging findings. The size of the tumor was 8×5.5×5 cm. The surface of the tumor was smooth, and the interior of the tumor contained a milky, creamy liquid. On histology done after surgery, the tumor was diagnosed as a tailgut cyst. A tailgut cyst is not frequently reported. The etiology is not known. Since about 10% of cases are malignant it is important that the possibility of malignancy should be considered before surgery, so as to select the appropriate surgical procedure.
