Aplastic anemia (AA) is a rare disorder caused by the failure of bone marrow to produce hematopoietic stem cells (HSCs), causing severe anemia, thrombocytopenia, and leukocytopenia. If untreated, AA has a very high mortality.

AA presents with pancytopenia, and bone marrow biopsy will reveal hypocellularity. It can be caused most commonly by autoimmune processes, direct injury to the bone marrow (toxic effect, drugs, radiation, etc), viral infection (eg, hepatitis B, hepatitis C, Epstein-Barr, cytomegalovirus, parvovirus B19, HIV), clonal disorders (eg, paroxysmal nocturnal hemoglobinuria, myelodysplastic syndrome, acute myeloid leukemia), or genetic disorders (eg, Fanconi anemia, Shwachman-Diamond syndrome, thrombopoietin abnormalities, telomere abnormalities). Despite the various pathophysiologic mechanisms that can lead to AA, the disorder remains rare, with an incidence in the Western world of 2 per million per year, with half of all cases occurring before the age of 30 years.

Patients with AA usually present with recurrent infections due to neutropenia, mucosal hemorrhage or menorrhagia due to thrombocytopenia, and fatigue, dyspnea, and cardiopulmonary compromise due to anemia.