Background : Serum carbohydrate antigen 19-9 (CA 19-9) level is used as a biomarker for diagnosis of pancreaticobiliary cancer. A very high serum carbohydrate antigen 19-9 (CA 19-9) is rarely present in an patient with obstructive jaundice caused by choledocholithiasis. This case reports a 56-year-old female presented with jaundice with extremely elevated CA 19-9 levels (>1000 U/mL).

Methods : Patient was initially diagnosed as a case of obstructive jaundice probably secondary to periampullary mass. Suspicions for malignancy prompted for diagnostics such as upper abdominal CT scan indicating a possible inflammatory stricture or neoplastic narrowing at the level of pancreatic head level. Laparotomy and intraoperative ultrasound was performed and demonstrated no tumor lesions within the periampullary area. Hence, intraoperative cholangiogram was performed revealing a filling defect within the distal common bile duct suggestive of stone. The patient underwent common bile duct exploration wherein we extracted a 2.5 x 1.5 cm solitary pigment stone.

Results : Postoperatively, CA 19-9 levels decreased within two (2) months.

Conclusions : This case indicates that CA 19-9 levels should not be the sole criterion for a diagnosis of malignancy. An extremely high value of CA 19-9 can be also reported in benign cause of obstruction. CA 19-9 levels should be used in conjunction with clinical evaluation and imaging studies for differentiating benign and malignant diseases.