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402 Part IV Disorders of Hematopoietic Cell Development

TABLE Severity of Aplastic Anemia as Defined by Laboratory TABLE Bone Marrow Morphologic Findings That Discriminate
30.6 Studies 30.7 Myelodysplasia From Aplastic Anemia
Severe aplastic anemia Characteristic a Myelodysplasia Aplastic Anemia
Bone marrow cellularity <30% Cellularity Usually normal to Decreased
Two of three peripheral blood criteria: increased
Absolute neutrophil count <500 cells/mm 3
Platelet count <20,000 cells/mm 3 Erythropoiesis
Reticulocyte count <40,000 cells/mm 3 Megaloblastic Very common Common
No other hematologic disease Dyserythropoietic Very common Unusual
Moderate aplastic anemia Maturation defects Common Not found
Patients with pancytopenia who do not fulfill the criteria of severe
disease Ringed sideroblasts Common Not found
Myelopoiesis
Monocyte prominence Very common Unusual
Midmyeloid predominance Very common Unusual
Diagnostic Algorithm in Aplastic Anemia Increased blasts Yes Not found
Megakaryocytes
Atypical morphology Very common Not found
PB counts
a Ringed sideroblasts and myeloblasts are observed by definition, in some of the
Low myelodysplastic syndromes. Dyserythropoietic red blood cell precursors show
bizarre forms with multiple or irregular nuclei. Megakaryocytes can show
Panacytopenia defective nuclear polyploidization and increased internuclear spaces, or they
can be small with only a few nuclei and peculiar granulation.
Adapted from Bagby GC: The preleukemic syndrome (hematopoietic dysplasia).
Blasts, dysplasia, In Shahidi NT (ed): Aplastic anemia and other bone marrow failure syndromes,
fibrosis New York, 1990, Springer-Verlag, p 199 (provides percentages for
BM for diagnosis MDS, AML myelodysplasia).
AMM
Karyotyping
Fat
AA Posttransfusion Graft-Versus-Host Disease
DEB, MMC
sensitive Almost uniformly fatal, AA is a constant feature of transfusion-
PB cytogenetics FA associated GVHD, produced by the transfusion of competent lym-
phocytes into immunodeficient hosts, including children with
congenital syndromes, cancer patients receiving high-dose chemo-
therapy, and patients with adoptive cellular immunotherapy for
Acquired AA leukemia. Rarely, posttransfusion GVHD occurs in an apparently
8
immunocompetent recipient in the special circumstance in which the
AA, Aplastic anemia; AML, acute myeloid leukemia; AMM, agnogenic myeloid donor is homozygous for an HLA haplotype also shared by the
metaplasia; BM, bone marrow; DEB, diepoxybutane; FA, Fanconi anemia;
MDS, myelodysplastic syndrome; MMC, mitomycin C; PB, peripheral blood. recipient, as can occur among first-degree family members. Small
numbers of lymphocytes are sufficient to produce the syndrome,
which is surprisingly resistant to immunosuppressive therapy. Pancy-
topenia with BM hypoplasia is an almost constant feature of post-
of heme. Pallor is common and is best appreciated on the mucous transfusion GVHD. Runt disease in animals is a model of this
membranes and palmar surfaces. The newly diagnosed patient can be immune-mediated BM failure syndrome.
febrile, but specific or localizing signs of infection are uncommon on
presentation. Cachexia, splenomegaly, and lymphadenopathy are not
associated with AA, and these findings should strongly suggest Pregnancy
another diagnosis. The examiner should look carefully for café-au-lait
spots and other physical anomalies of FA and for typical nail changes, Pregnancy is common in the age groups most susceptible to BM
leucoplakia, hypopigmentation of the skin and gray hair of telomere failure, and in many cases, its association is probably only coinci-
disease in children and adults. dental. The true frequency of AA in pregnancy is unknown, but
Several atypical presentations of AA should be noted. A physician from the number of cases reported, it appears rare, although BM
might encounter an elderly patient with pancytopenia in whom hypoplasia may be relatively common during pregnancy. A causal
subsequent BM examination reveals dysplastic features (see box on relationship is suggested by the temporal relationship between the
Diagnostic Algorithm in Aplastic Anemia and Table 30.7). Although onset of pancytopenia and that of pregnancy and by resolution after
the history of the illness in a newly diagnosed patient is typically delivery and spontaneous or induced abortion; some patients have
short—in the range of months—some patients may recall a long developed AA that remitted after each delivery. Survival rates for
history of bruisability, anemia, and low blood-cell counts reported to AA in pregnancy have been relatively high for the mother and baby,
them by previous physicians during routine examinations. These with most pregnancies successful. Hemorrhage is the most common
patients can have a moderately severe, chronic disease, and pancyto- cause of death from AA during pregnancy. The published data are
penia from childhood should suggest a constitutional AA. insufficient to guide management of the pregnant woman with AA,
especially because it is clear that AA in some cases is serendipitously
diagnosed and can persist beyond parturition. A woman who desires
CLINICAL ASSOCIATIONS a child can be maintained with transfusions, with the understand-
ing that any clinical deterioration is a criterion for interruption
A number of clinical syndromes, usually revealed through a careful or termination of the pregnancy. The hazard of pregnancy to the
history and physical examination, are associated with AA (see box on woman who has recovered from idiopathic AA is unknown, but most
Diagnostic Algorithm in Aplastic Anemia and Tables 30.2 and 30.3). hematologists, recognizing the risk of relapse, advise patients not to