Transcript MLAB 1315- Hematology Fall 2007 Keri Brophy

MLAB 1315- Hematology
Keri Brophy-Martinez
Unit 8: Morphological Changes
Associated with Disease
MORPHOLOGICAL CHANGES
ASSOCIATED WITH DISEASE

Evaluating and reporting anisocytosis (size) and
poikilocytosis (shape)
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RDW (red cell distribution width) is a measure expressed in percent of
the variation in the red cell volume distribution.
•
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Normal range: 11.5-14.0%
Grading scale
• Normal
slight variation from normal red cell
• Slight 5-10% of cells vary in size or shape from normal
red cell
• 1+
10-25% of cells vary in size or shape from
normal red cell (Few)
• 2+
25-50% of cells vary in size or shape from
normal red cell (Moderate)
• 3+
50-75% of cells vary in size or shape from
normal red cell (Many)
• 4+
>75% of cells vary in size or shape from normal
red cell (Marked)

Size variations (correlate with MCV and RDW)

Causes of macrocytes
• Caused by impaired DNA synthesis which leads to
decreased number of cell divisions resulting in a larger red
cell
• Accelerated erythropoiesis which results in increased
reticulocytes (retics are larger than mature red cells).

Causes of microcytes
• Impaired hemoglobin synthesis which may be caused by
iron problems
• Decreased or defective globin synthesis
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Stain variations
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Hypochromia (correlate with MCHC)
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1+
2+
3+
4+
area of central pallor is ½ of cell diameter
area of central pallor is of cell diameter
area of central pallor is ¾ of cell diameter
thin rim of hemoglobin
Polychromasia
• Describes the blue-gray color of immature RBC’s which
have left the bone marrow prematurely.
• These RBC’s are larger than normal.
• .he blue-gray color is due to residual RNA. When stained
with a supravital stain such as methylene blue, they are
called reticulocytes
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Shape variations

Target cell (codocyte)
• RBC’s have a centrally stained area and resemble a
shooting target.
• Caused by excess membrane cholesterol or decreased
hemoglobin content.
• Seen in liver disease, hemoglobinopathies, iron deficiency
anemia, post-splenectomy. Can also be artifactual.

Spherocyte
• Appear as small red cells with no central pallor; they have
the lowest surface area-volume ratio; shape change is
irreversible.
• Caused by loss of membrane due to aging, antibody
coating or genetic defect
• Seen in autoimmune hemolytic anemia, transfusion
reaction, hereditary spherocytic anemia.
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Ovalocyte/Elliptocyte
 Oval or cigar shaped red cells. May be normochromic or
hypochromic, normocytic or macrocytic.

Exact mechanism for deformity is not well defined.

Ovalocytes seen in myelodysplastic syndrome, thalassemia,
pernicious anemia, B12 or folate deficiency.
 Elliptocyes seen in iron deficiency anemia, hereditary elliptocytosis,
idiopathic myelofibrosis.
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Stomatocyte
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Normal size red cell with “slitlike” area of central pallor
resembling a mouth.
Exact mechanism for abnormality not well defined. Usually
artifactual
Seen in hereditary spherocytosis, hereditary
stomatocytosis, acute alcoholism, Rh null phenotype.

Sickle Cell (drepanocyte)
 Red cell is in the shape of a sickle or crescent.
 Caused by hemoglobin S polymerization into rigid inflexible cells
with at least one pointed projection. Polymerization occurs in
lowered oxygen level or decreased pH.
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Seen in hereditary condition called sickle cell disease. Can
be homozygous or heterozygous. Also seen in hereditary
Hemoglobin C disease or combination of both.
Acanthocyte
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Red cell of normal or slightly small size with 3-8 thorny,
spine-like projections that are irregularly spaced around the
cell. The projections may vary in length.
Exact mechanism is unknown, but it is known that they have
excess cholesterol and increased surface membrane.
Seen in congenital abetalipoproteinemia, alcohol
intoxication, severe hepatic disease and post-splenectomy

Fragmented red cells (Schistocytes, Burr cells, Helmet cells)
 Schistocytes
• Red cells appear as fragment of irregular size and shape.
• Caused by loss of membrane by mechanical means.
• Seen in patient with prosthetic heart valves, clostridial
infections, microangiopathic hemolytic anemia, hemolytic
uremic syndrome (HUS), thrombotic thrombocytopenia
purpura (TTP), disseminated intravascular coagulation
(DIC)

Helmet cells (also called bite cells)
• Red cells resemble an army helmet with short straps.
• Caused by splenic pitting.
• Seen in G6PD deficiency, pulmonary emboli and DIC.

Burr cells (echinocytes)
 Red cells have regular sharp projections around the
membrane.
 Caused by various factors such as dehydration or a change
in the tonicity of the intravascular fluid. Also can be
artifactual.
 Seen in renal disease, liver disease and burn patients

Variations in red cell distribution
 Agglutination
• Red cells clump together when cooled to room
temperature. Saline will not disperse the clumps, but
warming usually will.
• Caused by red cell antibodies
• Seen in cold antibody syndromes, paroxysmal cold
hemoglobinuria.

Rouleaux
• Red cells are arranged in groups resembling stacks of
coins. Saline will disperse the formations.
• Caused by elevated globulins or fibrinogen in the plasma.
• Seen in multiple myeloma and Waldenstroms’s
macroglobulinemia
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Red cell inclusions
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Howell-Jolly bodies
• Single round, solid-staining purple dot composed of DNA located
on the periphery of the RBC.
• Caused by accelerated or ineffective erythropoiesis in which
chromosome fragments are left in the cytoplasm.
• Seen following splenectomy and in thalassemias, hemolytic
anemias and megaloblastic anemia.

Basophilic stippling
• Tiny, round, solid-staining blue granules composed of RNA.
Can be diffuse, coarse or punctate
• Usually artifactual caused by precipitation of RNA during
staining of the smear.
• Seen defective or accelerated heme synthesis, lead
poisoning and thalassemias.
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Pappenheimer bodies (Siderotic granules in Prussian blue
stain)
 Purplish irregular aggregates of granules composed of
ferric(Fe3) iron.
 Caused by excess available iron throughout the body.
 Seen in sideroblastic anemia, alcoholism, thalassemia,
asplenism.
Heinz Bodies
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May not be seen on Wright’s stain. When
stained with a supravital stain such as crystal
violet or brillian cresyl blue, they appear as large
blue inclusions that are rigid and distort the cell
membrane.
Cause by denatured or precipitated hemoglobin.
Seen in alpha thalassemia, G6PD deficiency and
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Cabot ring
 Purplish ring-shaped, figure-eight, or loop-shaped structures
composed of nuclear membrane remnants. Rarely seen.
 Exact mechanism unkown
 Seen in pernicious anemia, lead poisoning, homozygous
thalassemia and post-splenectomy.