![A 46-year-old woman presented with diffuse bone pain. She had a history of acute myeloid leukemia with minimal differentiation (AML-M0) and normal karyotype diagnosed 15 months ago, achieved complete remission (CR) 1 month after beginning induction chemotherapy, and received 3 cycles of consolidation chemotherapy until 10 months before her current presentation. A complete blood count and peripheral smear at this time showed pancytopenia (hemoglobin 10.2 g/dL, white blood cells 3.8 × 109/L, platelets 67 × 109/L) and 37% blasts. The bone marrow was packed (95% cellularity) with immature myeloid cells that stained positively for CD13, CD33, CD41, CD61, and factor VIII and negatively for myeloperoxidase and CD3. Cytogenetic analysis revealed an abnormal female karyotype with 47,XX,+1,der(1;13)(q10;q10)[18]/46,XX[2] and a FLT3/TKD mutation. The aspirate showed frequent medium to large megakaryoblasts with pale blue-gray to basophilic cytoplasm, high nucleus-to-cytoplasm ratio, pseudopod formation, and cytoplasmic projections resembling budding atypical platelets (panels A-B). A diagnosis of AML-M0 relapsing as acute megakaryoblastic leukemia (AML-M7) was made. Although the patient has been receiving reinduction chemotherapy for the past 2 months, she has not achieved CR yet. / Cytoplasmic blebs and pseudopod formation are characteristic morphologic features of megakaryoblasts in AML-M7, which frequently appear in clusters mimicking metastatic tumors.](/view-large/figure/7362641/2537f1.jpeg)
A 46-year-old woman presented with diffuse bone pain. She had a history of acute myeloid leukemia with minimal differentiation (AML-M0) and normal karyotype diagnosed 15 months ago, achieved complete remission (CR) 1 month after beginning induction chemotherapy, and received 3 cycles of consolidation chemotherapy until 10 months before her current presentation. A complete blood count and peripheral smear at this time showed pancytopenia (hemoglobin 10.2 g/dL, white blood cells 3.8 × 109/L, platelets 67 × 109/L) and 37% blasts. The bone marrow was packed (95% cellularity) with immature myeloid cells that stained positively for CD13, CD33, CD41, CD61, and factor VIII and negatively for myeloperoxidase and CD3. Cytogenetic analysis revealed an abnormal female karyotype with 47,XX,+1,der(1;13)(q10;q10)[18]/46,XX[2] and a FLT3/TKD mutation. The aspirate showed frequent medium to large megakaryoblasts with pale blue-gray to basophilic cytoplasm, high nucleus-to-cytoplasm ratio, pseudopod formation, and cytoplasmic projections resembling budding atypical platelets (panels A-B). A diagnosis of AML-M0 relapsing as acute megakaryoblastic leukemia (AML-M7) was made. Although the patient has been receiving reinduction chemotherapy for the past 2 months, she has not achieved CR yet.
Cytoplasmic blebs and pseudopod formation are characteristic morphologic features of megakaryoblasts in AML-M7, which frequently appear in clusters mimicking metastatic tumors.
A 46-year-old woman presented with diffuse bone pain. She had a history of acute myeloid leukemia with minimal differentiation (AML-M0) and normal karyotype diagnosed 15 months ago, achieved complete remission (CR) 1 month after beginning induction chemotherapy, and received 3 cycles of consolidation chemotherapy until 10 months before her current presentation. A complete blood count and peripheral smear at this time showed pancytopenia (hemoglobin 10.2 g/dL, white blood cells 3.8 × 109/L, platelets 67 × 109/L) and 37% blasts. The bone marrow was packed (95% cellularity) with immature myeloid cells that stained positively for CD13, CD33, CD41, CD61, and factor VIII and negatively for myeloperoxidase and CD3. Cytogenetic analysis revealed an abnormal female karyotype with 47,XX,+1,der(1;13)(q10;q10)[18]/46,XX[2] and a FLT3/TKD mutation. The aspirate showed frequent medium to large megakaryoblasts with pale blue-gray to basophilic cytoplasm, high nucleus-to-cytoplasm ratio, pseudopod formation, and cytoplasmic projections resembling budding atypical platelets (panels A-B). A diagnosis of AML-M0 relapsing as acute megakaryoblastic leukemia (AML-M7) was made. Although the patient has been receiving reinduction chemotherapy for the past 2 months, she has not achieved CR yet.
Cytoplasmic blebs and pseudopod formation are characteristic morphologic features of megakaryoblasts in AML-M7, which frequently appear in clusters mimicking metastatic tumors.
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