S5636 Acute Myelomonocytic Leukemia Following Liver Transplantation

Introduction: Hematologic malignancies are uncommon but serious complications following solid organ transplantation, with acute myeloid leukemia (AML) being particularly rare. Among AML subtypes, acute myelomonocytic leukemia (AMML) is scarcely reported after liver transplantation (LT), and its pathogenesis and optimal management in this context remain poorly defined. We present a case of AMML which was successfully treated with early recognition and prompt therapy. Case Description/Methods: A 67-year-old man with history of MetALD cirrhosis complicated by hepatocellular carcinoma (treated with locoregional therapies) with history of LT 7 months prior with uncomplicated post-transplant course, who was admitted for evaluation of acute onset chest pain. Workup for cardiac and pulmonary etiologies was unremarkable. Laboratory workup showed WBC 15,800 cells/µL, alanine aminotransferase 23 U/L, aspartate aminotransferase 24 U/L, alkaline phosphatase 102 IU/L, and total bilirubin 0.8 mg/dL. White blood cell (WBC) count progressively increased despite empiric antimicrobials and broad infectious workup, with hospital WBC 54,700 cells/µL, with differential showing 61% monocytes on hospital day #14. Bone marrow biopsy was performed which showed findings consistent with favorable risk NPM 1-mutated AMML, with 61% blasts. Chromosome karyotype identified a pericentric inversion involving chromosome 4. He was treated with cytarabine and daunorubicin (7 + 3 induction), with successful remission, with consolidation treatment with high dose cytarabine. Immunosuppression with tacrolimus was closely managed in conjunction with transplant hepatology, and liver graft function remained stable throughout. He remains clinically well with no evidence of recurrence. Discussion: Malignancy is a well-established long-term complication of solid organ transplant. While hematologic cancers—including post-transplant lymphoproliferative disorders—are relatively more common, neoplasms such AML remain rare, with the AMML subtype seldom reported in LT recipients. Pathogenesis is likely multifactorial, involving cumulative immunosuppressive exposure, viral oncogenesis, and genetic instability. This case underscores the importance of early recognition and prompt therapy of hematologic abnormalities in LT recipients and demonstrates that favorable-risk AMML can be successfully treated with curative intent, even in the setting of immunosuppression for recent LT. Close surveillance and multidisciplinary care are critical in optimizing outcomes for this rare post-transplant complication.