Extramedullary hematopoiesis in primary myelobrosis presenting as upper gastrointestinal bleed

Abstract Primary myelofibrosis is a myeloproliferative neoplasm characterized by clonal proliferation of myeloid cells, megakaryotic proliferation, bone marrow fibrosis, extramedullary hematopoiesis (EMH) and leukoerythroblastosis. It is often due to JAK 2, MPL, or CAL mutations, though other mutations can also cause the disease. Patients usually present with severe fatigue, features of a hypermetabolic state, splenomegaly, and variable blood counts. EMH is also frequent in myeloproliferative neoplasm. It can arise anywhere in the body, even though the most involved sites are the liver, lymph nodes, and spleen. Risk stratification is done for prognosis and treatment initiation. Allogenic transplantation is the only curative treatment option for high-risk cases. Frequent transfusion requirements can arise in case of leukemic transformation, hypersplenism, or upper gastrointestinal (GI) bleeding. Here, we present a case of EMH in the GI tract presenting with an upper GI bleed.