Tailgut Cyst Associated With Marked Elevation of Serum Carbohydrate Antigen 19-9 : Report of a Case

We report herein an unusual case of a 59-year-old woman, with a tailgut cyst associated with elevated serum level of carbohydrate antigen (CA) 19-9. The patient was observed for 24 months after detection of a presacral cystic mass. Thereafter, the patient eventually consented to surgery. Preoperative serum CA19 -9 was markedly elevated (360.2 U/ml) but diagnostic imaging techniques did not demonstrate any evidence of malignancy in intra-or extra- cystic lesions. The cystic mass was excised via the transsacral approach. Pathological findings were compatible with tailgut cyst. The epithelium lining of the cystic wall was positive for CA19-9 but there were no findings of malignant change. The serum level of CA19-9 decreased to within the normal range 6 months postoperatively. The patient has remained well with no evidence of recurrence for 12 months postoperatively. This case suggests that a tailgut cyst can lead to a marked elevation of CA19-9 even without malignant change.