Unusual Cause Of Biliary Obstruction In A Post Liver Transplant Patient

INTRODUCTION: Biliary obstruction is not an uncommon phenomenon after liver transplantation. Common bile duct structuring (CBD) at the surgical anastomosis or ischemic stricturing are more common causes. We describe a delayed cause of biliary obstruction from a post transplant lymphoproliferative disorder of the transplanted liver. CASE DESCRIPTION/METHODS: 65 years old female with history of alcoholic/NASH cirrhosis/HCC status post kidney/liver transplantation 2 years ago presented with one week of pruritus, nausea, vomiting and abnormal liver and kidney tests. She was on mycophenolate 250 mg po BID, prednisone 5 mg daily and tacrolimus of 2 mg twice daily for immunosuppression. Physical examination was unremarkable on presentation. Labs showed creatinine of 2.6 from base line of 1.8. Alkaline phosphatase of 895 from base line of 131. AST/ALT 82/201. Total bilirubin was 1.7 on presentation. On subsequent days, creatinine peaked to 8 and bilirubin increased to 9.7. Liver ultrasound showed a heterogeneous echogenicity in the region of the porta hepatis along with mild intrahepatic biliary ductal dilatation and normal caliber CBD. MRI/MRCP showed infiltrative hepatic hilar mass with mild biliary obstruction. PET scan revealed an FDG avid central hepatic soft tissue mass. ERCP showed long region of hilar stenosis with dilation of left hepatic ducts. It was not possible to pass a guide wire through the stenosis and place a stent. EUS guided biopsy of the liver mass was done, but sample was not enough for diagnosis. A percutaneous transhepatic drainage tube was placed by interventional radiology to relieve the obstruction and percutaneous biopsy of the liver mass was done. The biopsy demonstrates a population of plasma cells and admixed lymphocytes and histiocytes involving the soft tissue around biliary type ducts. In situ hybridization for Epstein Barr virus showed scattered positive cells. CD3 and CD20 highlight scattered T and B cells respectively. Proliferation index of 30 - 40%.. Finding were consistent with Polymorphic Post-transplant lymphoproliferative disorder (PTLD). Patient was started on R-CHOP regimen chemotherapy. Renal function test improved with hydration. DISCUSSION: The principal risk factors for the development of a PTLD are the degree of immunosuppression and the EBV serostatus. An accurate diagnosis of PTLD requires a high index of suspicion. A tissue biopsy, preferably an excisional biopsy, with review by an expert hematopathologist, is required to ensure an accurate diagnosis.Figure 1.: MRI of abdomen- showing infiltrative hilar mass with biliary obstruction.Figure 2.: PET scan- Infiltrative heterogeneous FDG avid central hepatic mass.Figure 3.: ERCP-long region of hilar stenosis with dilation of left hepatic ducts.