CASE PRESENTATION
An 83-year-old male presented to the Tribhuvan University Teaching Hospital (TUTH) with complaints of yellowish discoloration of the eyes and abdominal discomfort, insidious in onset and gradually progressive for a month. He had dark-colored urine, clay-colored stool and pruritus. He also complained of anorexia, however, there was no significant weight loss. He did not have a fever, abdominal pain, vomiting, abdominal distension, gastrointestinal bleeding, and steatorrhea. There was no past history of jaundice. The patient was hypertensive and was under medication. He smoked 30 pack-years of cigarettes, and was a chronic alcoholic. On examination, he was icteric, and the abdomen was soft and non-tender without any organomegaly. Biochemical investigations showed conjugated hyperbilirubinemia and abnormal liver function as outlined in table 1. Hematological investigations, and serum amylase and lipase were within normal limits.
The ultrasonography (USG) of his abdomen and pelvis showed a normal scan. Contrast-enhanced computed tomography (CECT) scan of the abdomen and pelvis was then carried out which revealed a significantly narrowed lumen and mild thickening of the wall of the distal common bile duct (CBD) at the entrance of the pancreatic head with dilatation of upstream CBD and bilateral intrahepatic bile ducts (IHBDs). (Figure 1) These findings carried us to the possibility of distal cholangiocarcinoma. Therefore, the patient was further evaluated with serum levels of tumor markers, carbohydrate antigen 19-9 (CA 19-9: 8 U/ml; normal range 0-37 U/ml) the carcinoembryonic antigen (CEA: 3.91 ng/ml; range 0-5ng/ml), alpha fetoprotein (AFP: 5.24 ng/ml; range 10-20 ng/ml) which were within normal range. An endoscopic retrograde cholangiopancreatography (ERCP) was tried but the cannulation of the CBD failed due to a narrow lumen.
As a way out of this diagnostic riddle, the mass was suspected to be due to IgG4-SC and the serum level of IgG4 was tested which was found to be increased (more than 3.65 g/l). An oral steroid was started and the patient showed significant clinical improvement within a month, which further pointed the diagnosis toward IgG4-SC. The steroid was tapered and stopped at the end of the three months. The clinical improvement of the patient was accompanied by normalization of the liver functions (table 1), and a subsequent abdominal CT scan which showed normal CBD. The biopsy of the mass was planned during follow-up for the definitive diagnosis. However, the low financial status of the patient and his improvement with the steroid therapy curtailed its necessity. The patient was followed up for three years during which he had no symptoms of obstructive jaundice and abdominal pain. Also, abdominal CT scan and liver function tests (table 1) that were repeated during the follow-up were normal. Therefore, the higher level of serum IgG4, rapid improvement with steroid therapy, normal level of tumor markers and no recurrence of symptoms in the follow-up period of three years ruled-out malignancy, and the diagnosis of IgG4-SC was made.