Acute monocytic leukemia
Classification & external resources
Acute monocytic leukemia (AMoL, or AML-M5) is considered a type of acute myeloid leukemia. In order to fulfill World Health Organization (WHO) criteria for AML-5, a patient must have greater than 20% blasts in the bone marrow, and of these, greater than 80% must be of the monocytic lineage. A further subclassification (M5a versus M5b) is made depending on whether the monocytic cells are predominantly monoblasts (>80%) (acute monoblastic leukemia) or a mixture of monoblasts and promonocytes (<80% blasts). Monoblasts can be distinguished by having a roughly circular nucleus, delicate lacy chromatin, and abundant, often basophilic cytoplasm. These cells may also have pseudopods. By contrast, promonocytes have a more convoluted nucleus, and their cytoplasm may contain metachromatic granules. Monoblasts are typically MPO negative and promonocytes are MPO variable. Both monoblasts and promonocytes stain positive for non-specific esterase (NSE), however NSE may often be negative.
Additional recommended knowledge
Immunophenotypically, M5-AML variably express myeloid (CD13, CD33) and monocytic (CD11b, CD11c) markers. Cells may aberrantly express B cels marker CD20 and the NK marker CD56. Monoblasts may be positive for CD34.
M5 is associated with characteristic chromosomal abnormalities, often involving 11q23 or t(9;11)affecting the MLL locus, however the MLL translocation is also found in other AML subtypes. MLL is believed to be prognostically unfavorable in AML-M5 compared to other genetic alterations involving MLL such as t(9;11) The t(8;16) translocation in MLL is associated with hemophagocytosis.
AML-M5 is thought to be associated with exposure to epidophyllotoxins.
AML-M5 is treated with intensive chemotherapy (such as anthracyclines) or with bone marrow transplantation.
|Pathology: hematology (primarily C81-C96/200-208, D45-D47, D50-D77/280-289)|
|WBCs||hematological malignancy (lymphoma, leukemia, multiple myeloma), myeloproliferative disease, myelodysplastic syndrome|
-cytosis (Agranulocytosis, Leukocytosis, Lymphocytosis, Monocytosis) • -penia (Lymphopenia, Neutropenia)
|nutritional anemia: Iron deficiency anemia, Plummer-Vinson syndrome, Megaloblastic anemia (Pernicious anemia)|
hereditary hemolytic anemia: G6PD Deficiency, Thalassemia, Sickle-cell disease/trait, Hereditary spherocytosis, Hereditary elliptocytosis, Hereditary stomatocytosis
acquired hemolytic anemia: Autoimmune (Warm), HUS, MAHA, PNH, PCH
aplastic anemia: Acquired PRCA, Diamond-Blackfan anemia, Fanconi anemia • Sideroblastic anemia • Hemochromatosis
|Coagulation/platelets||coagulopathy: DIC • Hemophilia (A/VII, B/IX, C/XI, XIII) • Von Willebrand disease
Purpura: Henoch-Schönlein, ITP (Evans syndrome), TTP
primary hypercoagulable state: Protein C deficiency -
Protein S deficiency - Antithrombin III deficiency - Antiphospholipid syndrome - Factor V Leiden
other hemorrhagic conditions: Bernard-Soulier syndrome - Glanzmann's thrombasthenia - Grey platelet syndrome
|Histiocytosis||WHO-I Langerhans cell histiocytosis - non-Langerhans-cell histiocytosis/WHO-II (Juvenile xanthogranuloma, Hemophagocytic lymphohistiocytosis) - malignant histiocytic disorders/WHO-III (Acute monocytic leukemia, Malignant histiocytosis, Erdheim-Chester disease)|
|Other||Asplenia/hyposplenism - Methemoglobinemia|
|Hematological malignancy histology (ICD-O 9590-9989)|
|Lymphomas (9590-9759)||Hodgkin's lymphoma vs. Non-Hodgkin lymphoma - Diffuse lymphoma vs. Follicular lymphoma|
B-cell lymphoma (Small cell, Primary effusion, Diffuse large, ,Burkitt's, Splenic marginal zone, MALT)
mast cell tumor (Mast-cell sarcoma, Malignant mastocytosis, Malignant histiocytosis, Langerhans cell histiocytosis)
T-cell lymphoma (Cutaneous , Mycosis fungoides/Sézary's disease, Angioimmunoblastic, Anaplastic large cell, Hepatosplenic)
plasma cell (Plasmacytoma, Multiple myeloma)
|Immunoproliferative disorders (9760-9799)||Waldenström macroglobulinemia - Lymphomatoid granulomatosis|
|Lymphoid leukemias (9800-9839)||ALL - CLL - T-cell leukemia (Adult, Large granular lymphocyte, Prolymphocytic, Acute lymphoblastic) - B-cell leukemia (Prolymphocytic)|
|Myeloid leukemias (9840-9939, 9963)||AML (M2, APL/M3, AMoL/M5, Erythroleukemia/M6) - CML (CMoL, CNL, Philadelphia chromosome) - Granulocytic sarcoma|
|Other leukemias (9940-9949)||Hairy cell leukemia - Aggressive NK-cell leukemia|
|Myeloproliferative disease (9950-9961)||Polycythemia vera - Essential thrombocytosis - Myelofibrosis|
|Other (9964-9989)||Hypereosinophilic syndrome - Post-transplant lymphoproliferative disorder - Myelodysplastic syndrome|