This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Aplastic anemia can progress to all except - 
Select and explain. 
A. AML, B. Myelodysplastic anemia, C. Pure red cell aplasia, D. Paroxysmal nocturnal hemoglobinuria
C: Pure red cell aplasia
Answer: C: Pure red cell aplasia 
Explanation: PNH is the only hemolytic anemia caused by an acquired intrinsic defect in the cell membrane. PNH arises in the setting of aplastic anemia and these patients are at increased risk of developing acute myelogenous leukemia.
Aplastic anemia may progress to PNH and MDS.