A 35 year old female evaluated for anemia has a dry marrow tap and a peripheral smear showing tear drop cells. What is the most likely diagnosis?

In Primary Myelofibrosis, blood smear will show the characteristic features of extramedullary hematopoiesis: teardrop-shaped red cells, nucleated red cells, myelocytes, and promyelocytes. Marrow is usually not aspirable due to increased marrow reticulin, but marrow biopsy will reveal a hypercellular marrow with trilineage hyperplasia and increased numbers of megakaryocytes in clusters and large dysplastic nuclei. So the most likely diagnosis in this patient is Primary myelofibrosis. Splenomegaly due to extramedullary hematopoiesis may be massive to cause poal hypeension and variceal formation. The number of circulating CD34+ cells is markedly increased in PMF (>15,000/L). No specific therapy exists for PMF. Ref: Harrison's Internal Medicine, 18th Edition, Pages 898-902, 905-909, 934