S3459 A Case of Myeloid Sarcoma With Hepatic Involvement in a Patient With Pancytopenia

Introduction: Myeloid sarcoma is a rare cancer characterized by extramedullary tumors made of myeloblasts which occur in association with acute myeloid leukemia (AML) or other myeloproliferative disorders. Myeloid Sarcoma may involve any extramedullary site, but hepatic involvement has rarely been described. Case Description/Methods: A 62-year-old man presented to our hospital from an outside facility for pancytopenia. He reported symptoms of fatigue, malaise, recurrent falls, unintentional weight loss, dyspnea on exertion, and subjective fever. Labs were indicative of pancytopenia and hemolytic anemia with positive direct antiglobulin test suggestive of cold agglutinin disease with a titer of 1:64. Peripheral blood smear showed pancytopenia. Abdominal imaging showed splenomegaly and two mass-like regions of hypoattenuation in the right and left hepatic lobes with lack of mass effect on adjacent vasculature and vasculature passing through the masses suggestive of extramedullary hematopoiesis (Figure 1). Initial bone marrow biopsy showed markedly hypercellular marrow (∼95%) with trilineage hematopoiesis with erythroid prominence and dyspoiesis suggestive of myelodysplastic syndrome. Right hepatic lobe lesion biopsy showed a monotonous blast population replacing the liver tissue. Immunohistochemistry was positive for P53, CD43, CD45, CD117, and E-cadherin. Cytogenetic analysis showed two mutations in the tumor suppressor gene TP53. These findings were indicative of pure erythroid leukemia, a subtype of AML, with myelodysplastic related changes and hepatic myeloid sarcoma. Our patient underwent three cycles of chemotherapy – Cycle 1 – daunorubicin and cytarabine, Cycle 2 – daunorubicin, cytarabine, and venetoclax, and Cycle 3 – venetoclax and decitabine. Despite multiple lines of chemotherapy, he had progression of his disease and ultimately died after transitioning to hospice. Discussion: Myeloid sarcoma is an extremely rare neoplasm that has been described as extramedullary disease in AML. Variable clinical presentations with involvement of different organs such as lymph nodes, bones, skin, lungs, brain, bowels, pancreas, and stomach have made the diagnosis of Myeloid sarcoma challenging. Approaches to treatment have included systemic chemotherapy, surgical resection, radiation therapy, and hematopoietic stem cell transplantation. This case highlights the need to consider myeloid sarcoma in the differential diagnoses of hepatic lesions in the appropriate clinical setting.Figure 1.: MRI Liver showing left hepatic lobe lesion.