A patient has the following findings -splenomegaly, low RBC count, normal WBC, and platelet count and peripheral blood smear shows target cells. Repeated BM aspiration is unsuccessful. The probable diagnosis is -

Ans. is 'd' i.e., MyelofibrosisRepeated unsuccessful bone marrow aspiration clinches the diagnosis in our of myelofibrosis.o Aspiration of bone marrow is often unsuccessful in myelofibrosis because of extensive fibrosis of bone marrow (characteristic dry tap).