BACKGROUND: Carbohydrate tumor-associated antigen (CA 19-9) has been shown to be upregulated in other malignant tumors including gastric, ovarian, hepatocellular, and colorectal carcinoma as well as benign diseases of the biliary track such as pancreatitis, cholangitis, and choledocholithiasis. According to the available literature, in several cases of benign hydronephrosis and in a few cases of benign renal diseases, elevated CA 19-9 has been noted.

CASE REPORT: A 58-year-old Caucasian male patient was admitted in our clinic with complaints about blunt abdominal pain in the past two-month period localized in the right lumbar region and irradiating into the right inguinal area, constipation, abdominal bloating, and intermittent hematuria. The concentration of serum CA 19-9 was 3500 U/mL. Urine cytology provided no signs of abnormality. Intravenous urography visualized right-sided pyelon and ureter duplex with the defect in contrast shade of the pyelon, caused by a stag horn calculus. Contrast added computerized axial tomography of the abdomen and pelvis visualized the pyelon casted concretion spreading throughout the right pyelon, with ureterohydronephrosis with the distal block for passage of the contrast to the distal part of the ureter.

CONCLUSIONS: There is no doubt that CA 19-9 level is occasionally elevated in patients with obstructive urolithiasis as it was in our case. In the routine medical praxis, urolithiasis should not be neglected in the differential diagnosis of elevated concentrations of CA 19-9 marker.

Keywords: Antigens, Tumor-Associated, Carbohydrate - blood, Biomarkers - blood, Hydronephrosis - etiology, Urolithiasis - diagnosis