Myelofibrosis leading to a dry tap on bone marrow aspiration is seen with which of the following conditions?

In some acute megakaryocytic leukemias blasts show megakaryocytic differentiation,which is often accompanied by bone marrow fibrosis caused by the release of fibrogenic cytokines. Acute megakaryocytic leukemia is the most common variant of AML associated with Downs syndrome. The release od PDGF is responsible for marrow fibrosis.( ref Robbins 8th/622,9/e p612, Wintrobe12th/1857-8)