تسجيل الدخول

تسجيل

Extramedullary Acute Myeloid Leukemia

المؤلف:  Hoffman, R., Benz, E. J., Silberstein, L. E., Heslop, H., Weitz, J., & Salama, M. E.

المصدر:  Hematology : Basic Principles and Practice

الجزء والصفحة:  8th E , P974

2026-10-15

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AML blasts may infiltrate any tissue. A tumor composed of myeloid blasts is known as a myeloid sarcoma (or granulocytic sarcoma or chloroma). The term chloroma derives from the green hue of the tumor due to the presence of copper in MPO. Myeloid sarcomas can occur in any tissue but most commonly present in the skin (leukemia cutis), lymph nodes, gastrointestinal tract, testes, ovaries, CNS, soft tissue, and bones. They can easily be confused with lymphomas and soft-tissue sarcomas; immunohistochemical stains are often required to establish the correct diagnosis. Myeloid sarcomas can be isolated or multiple. Myeloid sarcomas may occur at the same time as blood and marrow involvement, may precede the diagnosis of AML in the marrow (primary extramedullary AML), or may occur at the time of relapse without marrow involvement. Isolated extramedullary relapse is particularly common following allo HSCT. Immune checkpoint inhibitors, such as the CTLA-4 inhibitor ipilimumab, appear to be particularly active in extramedullary relapse following allo HSCT. In the context of chronic myeloid malignancies (e.g., MDS, myeloproliferative neoplasms, chronic myeloid leukemia, chronic myelomonocytic leukemia), their appearance represents progression to a blast phase.

Myeloid sarcoma, even if primary extramedullary myeloid sarcoma, should be treated with systemic chemotherapy. In the absence of systemic therapy, subsequent progression to systemic AML is very likely in patients with primary extramedullary AML. Radiation therapy may be of help to optimize local control (especially if residual disease present after systemic therapy) and provide palliation. There is controversy over whether patients with myeloid sarcoma do better or worse than those with AML. It is likely that the prognosis depends more on the biologic features of the disease (e.g., presence of a CBF gene translocation) than on the extramedullary presentation.