Chapter 102. Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes (Part 1) Harrison's Internal Medicine > Chapter 102. Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes: Introduction The hypoproliferative anemias are normochromic, normocytic or macrocytic and are characterized by a low reticulocyte count. Deficient production of RBCs occurs with marrow damage and dysfunction, which may be secondary to infection, inflammation, and cancer. Hypoproliferative anemia is also a prominent feature of hematologic diseases that are described as bone marrow failure states; these include aplastic anemia, myelodysplasia (MDS), pure red cell aplasia (PRCA), and myelophthisis. Anemia in these disorders is often not a solitary or even the major hematologic finding. More frequent in bone marrow failure is pancytopenia: anemia, leukopenia, and thrombocytopenia. Low blood counts in the marrow failure diseases result from deficient hematopoiesis, as distinguished from blood count depression due to peripheral destruction of red cells (hemolytic anemias), platelets (idiopathic thrombocytopenic purpura or due to splenomegaly), and granulocytes (as in the immune leukopenias). Hematopoietic failure syndromes are classified by dominant morphologic features of the bone marrow (Table 102-1). While practical distinction among these syndromes usually is clear, they can occur secondary to other diseases, and some processes are so closely related that the diagnosis may be complex. Patients may seem to suffer from two or three related diseases simultaneously, or one diagnosis may appear to evolve into another. Many of these syndromes share an immune-mediated mechanism of marrow destruction and some element of genomic instability resulting in a higher rate of malignant transformation. Table 102-1 Differential Diagnosis of Pancytopenia Pancytopenia with Hypocellular Bone Marrow Acquired aplastic anemia Constitutional aplastic anemia (Fanconi's anemia, dyskeratosis congenita) Some myelodysplasia Rare aleukemic leukemia (AML) Some acute lymphoid leukemia Some lymphomas of bone marrow Pancytopenia with Cellular Bone Marrow Primary bone marrow diseases Myelodysplasia Paroxysmal nocturnal Secondary to systemic diseases Systemic lupus hemoglobinuria Myelofibrosis Some aleukemic leukemia Myelophthisis Bone marrow lymphoma Hairy cell leukemia erythematosus Hypersplenism B 12 , folate deficiency Overwhelming infection Alcohol Brucellosis Sarcoidosis Tuberculosis Leishmaniasis Hypocellular Bone Marrow ± Cytopenia Q fever Legionnaires' disease Anorexia nervosa, starvation Mycobacteria . Chapter 102. Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes (Part 1) Harrison's Internal Medicine > Chapter 102. Aplastic Anemia, Myelodysplasia, and. 102. Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes: Introduction The hypoproliferative. major hematologic finding. More frequent in bone marrow failure is pancytopenia: anemia, leukopenia, and thrombocytopenia. Low blood counts in the marrow failure diseases result from deficient hematopoiesis,