Our patient is a 59-year-old Southeast Asian male with past medical history significant for gastroesophageal reflux disease, hiatal hernia, and hyperlipidemia. He initially presented with low-grade fevers, generalized weakness associated with decreased appetite and weight loss. Subsequently, he noticed dark discoloration of the urine. He did not take any medications. He was a lifetime nonalcoholic and used to smoke occasionally (1-2 cigarettes/week). Family history was significant for diabetes mellitus, hypertension, myocardial infarction, and stroke. Initial laboratory work showed elevated liver enzymes and raised amylase, lipase (Table 1). Ultrasound and computerized tomography (CT) of the abdomen showed dilated common bile duct, dilated pancreatic duct, and enlarged lymph nodes in the porta hepatis, peripancreatic and perigastric regions. A hypoechoic mass measuring 3 by 4 cm was seen in the pancreatic head. There was a strong suspicion of pancreatic carcinoma (Figure 1).
Endoscopic ultrasound- (EUS-) guided fine needle aspiration (FNA) of the pancreatic mass showed reactive atypia with no evidence of malignancy and celiac lymph node FNA cytology showed atypical cells with granuloma (Figures 2(a) and 2(b)). Quantiferon gold came back positive and mycobacterium tuberculosis (MTB) DNA was detected via polymerase chain reaction (PCR) from the biopsy specimen. Tumor markers including CA19-9 (carbohydrate antigen 19-9), AFP (alpha-fetoprotein), CA 125 (cancer antigen 125), and CEA (carcinoembryonic antigen) were normal. Angiotensin converting enzyme level was also within normal limits. Subsequently, the patient developed jaundice associated with fever. Endoscopic retrograde cholangiopancreatography (ERCP) was done and a biliary stent was placed in the common bile duct. Biopsy from the distal common bile duct also showed granulomatous inflammation. Patient was started on antituberculosis treatment (ATT) with rifampin 600 mg, ethambutol 1200 mg, isoniazid 300 mg, and pyrazinamide 1500 mg, which he tolerated well. IgG4 came back positive at 0.5 g/L (0.25 g/L-0.318 g/L) leading to suspicion of autoimmune pancreatitis. He was also started on prednisolone 40 mg orally every day. One month after the initiation of treatment, a repeat CT scan of the abdomen did not show any changes in the size of the pancreatic head mass or lymph nodes.
Six months after initial presentation, he developed an episode of acute pancreatitis. By this time he was on ATT for five months and prednisolone for four months. CT scan showed increase in the size of lymph nodes and persistent common bile duct and pancreatic duct dilatation (Figure 3). Another ERCP was performed with stent exchange and retrieval of few gallstones. Pancreatic mass and the pancreatic duct could not be reached. EUS-guided biopsy of the lymph node showed reactive hyperplasia and was negative for malignancy or granuloma. MTB DNA was negative. Ampullary tissue biopsy also showed inflammatory changes. Magnetic resonance cholangiopancreatography (MRCP) was also performed which showed persistent enlarged lymph nodes and enlarged pancreatic duct but some regression of pancreatic mass.
Patient completed a total of eighteen months of ATT and was tapered off steroids as well. Follow-up laboratory tests showed normal liver function test, amylase and lipase level (Table 1). IgG4 levels also decreased to a normal range (Table 1). He had a few episodes of self-resolving nausea and abdominal pain. Imaging studies including CT, ultrasound, and MRCP repeated after completing ATT and steroids continued to show enlarged lymph nodes in the porta hepatis, peripancreatic regions, dilated CBD, and pancreatic duct with atrophic looking pancreas (Figures 4(a) and 4(b)). At present, patient is doing well with minimal symptoms and is able to maintain weight.