P-010 Small Duct Primary Sclerosing Cholangitis. A Rare Entity

Abstract

26 years old male, recently diagnosed with Ulcerative colitis (UC) presented with elevated liver enzymes. With the history of UC, Primary Sclerosing Cholangitis (PSC) was suspected. Right upper quadrant Ultrasound was noted for only slight dilatation of common bile duct. Patient underwent Magnetic Resonance Cholangiopancreatograpy (MRCP) which showed abnormal fullness at the junction of the head and body of the pancreas but normal bile ducts. Endoscopic Ultrasound was done which suggested normal bile ducts and pancreatic head lymph node enlargement but cytology was negative for malignancy. Patient continued to have persistent elevation of liver enzymes. MRCP was repeated, showing same fullness in pancreas without extrahepatic biliary abnormality. Meanwhile extensive immunological and infectious work up was negative. Finally Liver biopsy was done which revealed intrahepatic biliary injury and obstruction consistent with small duct Primary sclerosing cholangitis. Discussion(s): Small duct primary sclerosing cholangitis or pericholangitis is variant of PSC involving small caliber bile ducts. It has biochemical and histological features similar to classic PSC. Only a small number of patients with small duct PSC have so far been reported. It has been proposed that patients with small duct PSC would eventually develop large duct PSC but may have better prognosis than classic PSC. The most common criteria for diagnosis of small duct PSC that have been proposed are occurrence of biochemical features of chronic cholestasis, liver histology compatible with PSC, normal cholangiogram, and concomitant IBD. An important part of the mortality in PSC is due to cholangiocarcinoma but there have been different studies with contradictory reports of association of cholangiocarcinoma with small duct PSC and further large scale studies are needed. Conclusion(s): Small duct PCS should be considered as differential when patient with IBD has abnormal liver function tests but unremarkable imaging studies. Patients with small duct PSC seem to have a good prognosis in terms of risk of progression of liver disease and cholangiocarcinoma.