S5792 Biliary Injury Mimicking Graft Versus Host Disease After Autologous Stem Cell Transplant

Introduction: Hematopoietic stem cell transplant is an integral treatment for hematological malignancies, such as multiple myeloma. Allogenic stem cell transplant has a higher rate of transplant-related mortality and risk of serious complications compared to autologous stem-cell transplant (auto-SCT). However, auto-SCT is also associated with several side effects, many of which are understudied. In this case, we describe a patient with biliary injury and stricturing mimicking graft-versus-host disease (GVHD) and primary sclerosing cholangitis (PSC) after auto-SCT. Case Description/Methods: A 64-year-old woman with IgA lambda multiple myeloma received an auto-SCT after standard melphalan conditioning. Her early transplant course was uncomplicated. Labs drawn post-discharge revealed aspartate aminotransferase 99, alanine aminotransferase 127, alkaline phosphatase 903, gamma-glutamyl transferase 480 and normal TBili. RUQUS showed an enlarged heterogenous liver with no steatosis and no focal solid mass. The patient was ordered for Fibro-Scan, chronic liver disease labs, MRCP, and liver biopsy. Fibroscan showed S0, F0 <6.5 kPa, and all other laboratory workup was negative. MRCP showed diffuse irregularity of the central intra- and extrahepatic bile ducts concerning for PSC, and biliary strictures suggestive of GVHD. Liver biopsy showed bile duct injury/loss, minimal portal lobular inflammation, periportal and focal pericellular fibrosis (0-1/4) with overall findings most consistent with GVHD. The patient’s LFTs remained elevated, though synthetic function remained intact, and she was managed with serial LFTs and yearly MRCP. Discussion: This is a rare case of auto-SCT causing bile duct injury, fibrosis and stricturing. Liver biopsy did not show small duct PSC, and the patient did not have associated clinical features to support this diagnosis. Furthermore, GVHD in the setting of auto-SCT is not clinically compatible and essentially non-existent. Prior studies have documented biliary cast syndrome (BCS) and benign biliary strictures (BBS) after allogenic-SCT, but not in auto-SCT. Cholestatic drug-induced liver injury (DILI) has been documented to occur in auto-SCT specifically after melphalan conditioning in one retrospective cohort study. The pathophysiology of this finding is not yet well understood, and in this case, may represent a unique manifestation of DILI. Further investigation into liver toxicities specifically associated with auto-SCT is warranted.