Page 342 - Textbook of Pathology, 6th Edition

326 3.Thrombocytopenia. Platelet count is always reduced. marrow transplantation are: acute leukaemias—AML in first
4.Bone marrow examination. A bone marrow aspirate remission and ALL in second remission, thalassaemia major
may yield a ‘dry tap’. A trephine biopsy is generally and combined immunodeficiency disease). Complications of
essential for making the diagnosis which reveals patchy bone marrow transplantation such as severe infections, graft
cellular areas in a hypocellular or aplastic marrow due to rejection and graft-versus-host disease (GVHD) may occur
replacement by fat. There is usually a severe depression (Chapter 4).
of myeloid cells, megakaryocytes and erythroid cells so Severe aplastic anaemia is a serious disorder terminating
that the marrow chiefly consists of lymphocytes and in death within 6-12 months in 50-80% of cases. Death is
plasma cells (Fig. 12.35). Haematopoieitc stem cells usually due to bleeding and/or infection.
bearing CD34 marker are markedly reduced or absent. MYELOPHTHISIC ANAEMIA

Treatment Development of severe anaemia may result from infiltration
of the marrow termed as myelophthisic anaemia. The causes
The patients of mild aplasia may show spontaneous recovery, for marrow infiltrations include the following (Table12.14):
while the management of severe aplastic anaemia is a most Haematologic malignancies (e.g. leukaemia, lymphoma,
challenging task. In general, younger patients show better myeloma).
response to proper treatment. The broad outlines of the Metastatic deposits from non-haematologic malignancies
treatment are as under: (e.g. cancer breast, stomach, prostate, lung, thyroid).
A. General management: It consists of the following: Advanced tuberculosis.
SECTION II
1. Identification and elimination of the possible cause. Primary lipid storage diseases (Gaucher’s and Niemann-
2. Supportive care consisting of blood transfusions, platelet Pick’s disease).
concentrates, and treatment and prevention of infections. Osteopetrosis and myelofibrosis may rarely cause
B. Specific treatment: The specific treatment has been myelophthisis.
attempted with varying success and includes the following: The type of anaemia in myelophthisis is generally
1. Marrow stimulating agents such as androgen may be normocytic normochromic with some fragmented red cells,
administered orally. basophilic stippling and normoblasts in the peripheral blood.
2. Immunosuppressive therapy with agents such as anti- Thrombocytopenia is usually present but the leucocyte count
thymocyte globulin and anti-lymphocyte serum has been is increased with slight shift-to-left of myeloid cells i.e. a
tried with 40-50% success rate. Very high doses of picture of leucoerythroblastic reaction consisting of immature
glucocorticoids or cyclosporine may yield similar responses. myeloid cells and normoblasts is seen in the peripheral blood.
But splenectomy does not have any role in the management Treatment consists of reversing the underlying pathologic
of aplastic anaemia. process.
3. Bone marrow transplantation is considered in severe cases PURE RED CELL APLASIA
under the age of 40 years where the HLA and mixed culture- Pure red cell aplasia (PRCA) is a rare syndrome involving a
matched donor is available. (Other indications for bone selective failure in the production of erythroid elements in
the bone marrow but with normal granulopoiesis and mega-
karyocytopoiesis. Patients have normocytic normochromic
anaemia with normal granulocyte and platelet count.
Reticulocytes are markedly decreased or are absent.
PRCA exists in the following forms:
Transient self-limited PRCA: It is due to temporary marrow
Haematology and Lymphoreticular Tissues
failure in aplastic crisis in haemolytic anamias and in acute
B19 parvovirus infection and in transient erythroblastopenia
in normal children.
Acquired PRCA: It is seen in middle-aged adults in asso-
ciation with some other diseases, most commonly thymoma;
others are connective tissue diseases (SLE, rheumatoid
arthritis), lymphoid malignancies (lymphoma, T-cell
chronic lymphocytic leukaemia) and solid tumours.
Chronic B19 parvovirus infections: PRCA may occur from
chronic B19 parvovirus infection in children and is common
and treatable. B19 parvovirus produces cytopathic effects on
the marrow erythroid precursor cells and are charac-
Figure 12.35 Bone marrow trephine biopsy in aplastic anaemia teristically seen as giant pronomoblasts.
contrasted against normal cellular marrow. A, normal marrow biopsy Congenital PRCA (Blackfan-Diamond syndrome) is a rare
shows about 50% fatty spaces and about 50% is haematopoietic marrow chronic disorder detected at birth or in early childhood. It
which contains a heterogeneous mixture of myeloid, erythroid and
lymphoid cells. B, In aplastic anaemia, the biopsy shows suppression of occurs due to mutation in a ribosomal RNA processing gene
myeloid and erythroid cells and replacement of haematopoetic elements termed as RPS19. The disorder is corrected by glucocorticoids
by fat. There are scanty foci of cellular components composed chiefly of and marrow transplantation.
lymphoid cells.
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