Question | Answer |
instances where acute leukemia can be diagnosed without the presence of 20% blasts | AML with following translocations: t(8;21) t(15;17) or inv(16) |
general morphologic features of myeloblasts | high N/C ratio, finely dispersed nuclear chromatin, 1 to multiple nucleoli, possible presence of fine granules or reddish-pink Auer rods; may be myeloperoxidase + |
left shift | granulocytes and rare blasts seen peripherally in blood, usually normal reaction to mod-severe infections especially in children |
pathologic associations of AML | exposure to radiation or chemo in the past, increased risk if prior CML, loose association with paroxysmal nocturnal hemoglobinuria |
differences in cytogenetics of AML in groups younger than 40 y/o and those with median age of 65 | those < 40 y/o: usually balanced translocation // those > 65 y/o usually have > 3 cytogenetic aberrations from accumulation of mutations, portends worse prognosis |
how AML is diagnosed | when > 20% myeloblasts are seen in the blood or bone marrow |
AML with monoblastic differentiation | cells with pale gray colored cytoplasm more abundant than myeloblast, fine & lacy chromatin with round or folded nucleus; nonspecific esterase + but MPO -, may express CD14, CD36, and/or CD6 |
markers of immature myelocytes (myeloblasts) | CD34 is present on pluripotent hematopoietic stem cells and progenitor cells of many lineages; CD117 is hemato. stem cell growth-factor receptor |
markers of any myeloblast | CD13, 33 |
leukocyte common antigen | CD45 |
AML with t(8;21) or RUNX1/RUNX1T1 | occurs in younger pts, typically myeloblasts with spectrum of neutrophilic maturation, dysplastic features like abnl segmentation and hypogranulation, single Auer rods in blasts and mature neutrophils; favorable prognosis |
markers of monoblastic lineage | CD14, 36 and MAYBE 64 |
main cellular effect of t(8;21) or inv(16) in myeloblasts | defect of core-binding factor & inhibition of normal myeloblast maturation |
AML with inv(16) or CBFB/MYH11 | mostly younger pts, typically mixture of myeloblasts and monoblasts with abnormal eosinophilic precurors, may have Auer rods, may be MPO (myelo) or non-specific esterase + (mono); fairly good prognosis |
main cellular effect of t(15;17) in myeloblasts | fusion of the PML gene on chromosome 15 and the retinoic acid receptor-α (RARα) gene on chromosome 17 resulting in the PML-RARα fusion gene |
AML with t(15;17) aka APL or PML/RARA | middle-aged adults, frequently presents as emergency DIC, typified by promyelocytes, "sliding plate" bi-lobed nuclei and dense purple granules, mult Auer rods, MPO+, microgranular variant, favorable prognosis when treated with all-trans retinoic acid |
molecular markers for APL | CD34- and CD117+ |
AMl with myelodysplasia-related changes | up to 35% of all AMLs, older pts, arises from prev diagnosed myelodysplastic syndrome, demonstrates cytogenetic abnormalities associated with myelodysplasia and sig degree of multilineage dysplasia, poor prognosis |
AML, therapy-related | occurs as late complication of chemo or radiation for prior malignancy; implicated by drugs like alkylating agents, topo inhibitors, antimetabolites and antitubulin agents, often complex karytoype and poor prognosis |
myelodysplastic syndromes | causes ineffective hematopoiesis causing peripheral cytopenias and hyperplastic bone marrow, high risk of transformation into AML; associated with environmental exposures or prev chemo/radiation, which portends a poorer prognosis |
histologic characteristics of myelodysplasia | hypogranular and hypolobulated neutrophils, anisopoikilocytosis, basophilic stippling in nucleated RBCs, large and hypogranular plts, immature monocytes |
pseudo-Pelger-Huët neutrophils | cells typical of myelodysplastic syndromes |
dyspoiesis | seen in MDS = micromegakaryocytes and multinucleated forms with each nucleus having its own single lobe, multinucleated erythroid precursors, megaloblastoid changes or RBCs, nuclear fragmentation and apoptosis seen throughout |
characteristics of chronic myeloproliferative neoplasms | hypercellular bone marrow with intact maturation and minimally disturbed cytological appearance; pt presents with fatigue malaise weight loss gout extramedullary hematopoiesis BASOPHILIA |
chronic myelogenous leukemia (CML | type of CMPN, almost always typified by Philadelphia chr t(9;22) making bcr-abl fusion gene; neoplastic pluripotent BM stem cells causes marked leukocytic proliferation with wide array of maturational stages |
phases of CML | chronic phase - about nl blast count in BM of ~ 5% // accelerated phase - > 10% blasts // acute blastic or leukemic phase = more than 20% blasts |
polycythemia vera (PV) | CMPN with increased RBC production independent of nl erythropoiesis regulation; accompanied by increase in megakaryocytes and (maybe myeloid elements) |
cytogenetic abnormality of PV | mutation in exon 14 of JAK2 gene resulting in V617F substitution /// |
clinical features of PV | HTN and thrombotic episodes due to Hct being near or > 60%, WBCs from 12-50K, plts > 500K, low erythropoietin levels; pruritis, dizziness, paresthesias, erythromelalgia, visual disturbances |
consequence of advanced PV | severe bone marrow fibrosis and extramedullary hematopoiesis, called post-polycythemic stage. may also see absence of storage iron in BM due to sustained erythrocytosis |
chronic myelofibrosis (CM) | CMPD typified by increased in all myeloid cells but specifically megakaryocytes that drive abnormal reticular fiber and collagen deposition in the BM; half have the JAK2-V617F mutation |
clinical features of CM | pts usually asymptomatic until BM is fibrosed and signs of extramedullary hematopoiesis develop like splenomegaly. leukocytosis from 15-30K, occasional blasts, basophilia, circulating nucleated RBCs with L shift, megakaryocytic fragments, dry-tap BM |
leukoerythoblastic rxn | seen in chronic myelofibrosis = circulating nucleated RBCs with increased numbers of blastic leukocytes |
essential thrombocythemia (ET) | CMPD involving mainly megakaryocytes, dx'ed by sustained thromobcytosis of > 450K, half have JAK2-V617F |
clinical features of ET | multiple placental infarcts causing recurrent abortions, fetal growth retardation, transient cerebral ischemias, paresthesias, digital ischemia from microvascular occlusion |
histological appearance of ET | sizable clumps of plts on bone marrow aspirate, maybe be normocellular or mildly hypercellular, marked proliferation of enlarged megakaryocytes with nuclear hyperlobation |