DIC is common in which AML –
**Core Concept**
Acute Myeloid Leukemia (AML) is a heterogeneous group of malignancies characterized by the clonal expansion of myeloid blasts in the bone marrow. Disseminated Intravascular Coagulation (DIC) is a serious complication associated with certain subtypes of AML. The pathogenesis of DIC in AML involves the release of procoagulant substances, such as tissue factor, from the leukemic cells and the activation of the coagulation cascade.
**Why the Correct Answer is Right**
Promyelocytic leukemia (AML-M3) is a subtype of AML characterized by the accumulation of promyelocytes in the bone marrow and peripheral blood. AML-M3 is known to be associated with a high risk of DIC due to the release of granules from the promyelocytes, which contain tissue factor and other procoagulant substances. The activation of the coagulation cascade leads to the formation of microthrombi in the small blood vessels, resulting in DIC. The high frequency of DIC in AML-M3 is thought to be due to the unique biology of this subtype, which involves the expression of tissue factor and other procoagulant molecules.
**Why Each Wrong Option is Incorrect**
**Option A:** Nonocytic (M5) AML is a subtype of AML characterized by the accumulation of monocytes in the bone marrow and peripheral blood. While nonocytic AML can be associated with a high risk of infections and bleeding, it is not typically associated with DIC.
**Option C:** Erythrocytic (M6) AML is a subtype of AML characterized by the accumulation of erythroblasts in the bone marrow and peripheral blood. Erythrocytic AML is not typically associated with DIC.
**Option D:** Megakaryocytic (M7) AML is a subtype of AML characterized by the accumulation of megakaryoblasts in the bone marrow and peripheral blood. Megakaryocytic AML can be associated with a high risk of bleeding due to thrombocytopenia, but it is not typically associated with DIC.
**Clinical Pearl / High-Yield Fact**
AML-M3 is also known as acute promyelocytic leukemia (APL). APL is characterized by a unique chromosomal translocation, t(15;17), which leads to the formation of a PML-RARA fusion gene. The PML-RARA fusion gene is thought to play a key role in the pathogenesis of APL and the development of DIC.
**Correct Answer:**
✓ Correct Answer: B. Promyelo cytic (M3)