MPO and myeloproliferative neoplasm: The tumor is also called chloroma, extramedullary myeloid tumor, or myeloid sarcoma (MS), which generally presents with a green color due to the presence of myeloperoxidase (MPO).[1–2] GS usually occurs with acute myelocytic leukemia (AML), myelodysplastic syndrome, myeloproliferative neoplasm or as a recurrence of AML.