<prompt> Myelofibrosis leading to a dry tap on bone marrow aspiration is seen with ach of the following conditionBurkitts lymphomaAcute erythroleukemiaAcute megakaryocytic leukemiaAcute myelomonocytic leukemia  <response>: Ans. c. Acute megakaryocytic leukemia Bone marrow maybe difficult to aspirate in Acute megakaryocytic leukemia and more than 23rd of patients have significant fibrosis caused by release of fibrogenic cytokine Erythroleukemia M6 FAB Bone marrow findings: Usually hypercellular with megaloblastic changesdeg - Erythroid precursors commonly have multicentricity 65, karyorrhexis 53, morulae 25 and cytoplasmic inclusionsdeg. MC immunophenotypic marker for erythroleukemia: Glycoprotein 7 and transferring receptor CD-71 Acute Megakaryocytic Leukemia M7 FAB Bone marrow findings: Bone marrow maybe difficult to aspirate and more than 23 of patients have significant fibrosisdeg caused by release of fibrogenic cytokine Burkitts Lymphoma Bone marrow findings: When the bone marrow is involved, aspirates reveal tumor cells with slightly clumped nuclear chromatindeg, 2-5distinct nucleoli and royal blue cytoplasm containing clear cytoplasmic vacuole Acute Myelomonocytic Leukemia M4 FAB Bone marrow findings: Ultra-structures are present in association with monocytosis and myeloblasticmonoblastic infiltration of bone 