Red Cell Morphology Basic Introduction Reference: Color Atlas of Hematology by Eric Glassy, M.D.
RBC Classification SIZE Normocyte Microcyte Macrocyte Anisocytosis SHAPE Acanthocytes Burr Cells Ovalocytes Tear Drops Stomatocytes Spherocytes Schistocytes Target Cells Sickle Cells PALLOR Normochromic Hypochromic Hyperchromic Polychromasia INCLUSIONS NRBC’s Howell-Jolly bodies Basophilic Stippling Pappenheimer bodies Hemoglobin crystals
RBC Parameters MCV = X – 100 fL MCH = X – 31 pg/cell MCHC = X – 36 g/dL Hct_ RBC Hgb_ RBC Hgb_ Hct Microcytic 100 fL Hypochromic 36 g/dL
Normal RBC
Normal RBC 50x Objective
Normal RBC 100x Objective
Microcytes SYNONYMS: microcytic RBCs KEY FEATURES: –Size: MCV < 80 fL; diameter < 6 m –Cytoplasm: normochromic or often hypochromic with increased central pallor
Microcytic Compare RBC and Lymph sizes
Macrocytes SYNONYMS: macrocytic RBCs; macro-ovalocyte (oval form) KEY FEATURES: –Size: MCV > 100 fL; diameter > 8 m –Shape: round or oval –Cytoplasm: normochromic, but may sometimes be hypochromic; no polychromasia
Macrocytes Compare RBC and Lymph sizes
Anisocytosis Size Variation RDW Guide (g/dL) Slight = Moderate = Marked = > 26 Only use RDW as a guide
Hypochromia SYNONYMS: hypochromic RBCs KEY FEATURES: –Size: microcytic or macrocytic cells –Cytoplasm: central pallor > 1/3 of RBC diameter (increased central pallor); some cells contain so little hemoglobin that they are “ghost cells”
Microcytic – Hypochromic Compare RBC and Lymph sizes
Polychromasia SYNONYMS: polychromatophil; reticulocyte (presumptive) KEY FEATURES: –size: slightly larger than erythrocyte –shape: round to slightly oval –cytoplasm: little or no central pallor; color is slightly more gray-blue or purple than that of an erythrocyte
Polychromic
Acanthocytes SYNONYMS: spur, spike or horn cell APPEARANCE: Crenated RBC with very spiny, irregular projections KEY FEATURES: –Size: diameter smaller than normal cells (like spherocytes) –Shape: 3 – 20 irregular membrane spikes, unevenly distributed –Cytoplasm: no central pallor
Acanthocytes
Burr Cells SYNONYMS: Echinocyte, crenated cell APPEARANCE: Similar to crenated RBCs but projections are less pointed and more regular than acanthocytes KEY FEATURES: –Size: normocytic –Shape: evenly distributed short, blunt or pointed spicules; projections uniformly sized –Cytoplasm: normochromic; retains central pallor (unlike acanthocytes)
Burr Cells
Elliptocytes SYNONYMS: ovalocyte, pencil cell APPEARANCE: elongate with round ends (cigar, egg, pencil shapes) KEY FEATURES: –Size: variable; usually longer than normal red cell and much more narrow –Shape: uniform, symmetrical rod shape; sides nearly parallel –Cytoplasm: often retain central pallor
Elliptocytes
Teardrop Cells SYNONYMS: dacrycocyte APPEARANCE: Round cells with elongated tail or point; resembles a teardrop KEY FEATURES: –Size: microcytic to normocytic –Shape: teardrop or pear-shaped RBC with single tapered end (tail) that is blunt or round –Cytoplasm: normochromic to hypochromic
Teardrop Cells
Stomatocytes SYNONYMS: hydrocyte APPEARANCE: RBC with a slit-like central pallor KEY FEATURES: –Size: normocytic –Shape: round; uniconcave disc –Cytoplasm: normochromic; central pallor appears slit-like, straight, fishmouth, or curved rod-shaped; a few cells may have tri-polar pallor creating cells that resemble sleigh bells
Stomatocytes
Spherocytes SYNONYMS: none APPEARANCE: Cells appear perfectly round and have no central pallor; often smaller than normal RBCs KEY FEATURES: –Size: slightly microcytic –Shape: round to spherical –Cytoplasm: no central pallor
Spherocytes 50x Objective
Spherocyte 100x Objective
Schistocytes SYNONYMS: helmet cell, triangulocyte, keratocyte, horn cell, fragmented RBCs APPEARANCE: Pieces of RBCs that can have a vast variety of shapes and sizes KEY FEATURES: –Size: irregular cell sizes; usually microcytic –Shape: shapes vary from helmet to triangular to unclassified fragments –Cytoplasm: small fragments lack central pallor; horn cells can be normochromic
Schistocytes Fragmented RBCs
Target Cells SYNONYMS: codocyte APPEARANCE: RBCs have a bullseye appearance KEY FEATURES: –Size: normocytic to slightly macrocytic –Shape: round –Cytoplasm: increased surface membrane to volume ratio results in a central, darker hemoglobin region within the area of central pallor creating the appearance of a target or bullseye
Target Cells
Sickle Cells SYNONYMS: drepanocyte APPEARANCE: Usually a thin, crescent shaped cell KEY FEATURES: –Shape: sickle shaped with at least one pointed end; may also be crescent-shaped, boat- shaped, filament shaped, holly-leaf form (rarely) and envelope shaped –Cytoplasm: no central pallor; very dense hemoglobin concentration (normochromic to hyperchromic)
Sickle Cells 50x Objective
Sickle Cells 100x Objective
RBC Inclusions NRBCs Howell-Jolly Bodies Basophilic Stippling Pappenheimer Bodies Hemoglobin Crystals
Nucleated Red Blood Cells SYNONYMS: NRBCs APPEARANCE: RBC with a small, pyknotic nucleus with dense chromatin KEY FEATURES: –Size: 8-10 m size; slightly larger than a mature RBC –Cytoplasm: varies depending on stage of maturation; usually more blue-gray
NRBCs Nucleated RBC
NRBCs
Howell-Jolly Bodies SYNONYMS: nuclear fragment, HJ bodies, Ho-Jo’s APPEARANCE: Large, singular dark purple inclusion KEY FEATURES: –Size: 1 m; sometimes as small as 0.5 m –Shape: spherical or oblong blue-purple or blue-black inclusion –Cytoplasm: normochromic or hypochromic –Location: eccentrically located (off center); usually a single inclusion, but multiple can be present
Howell-Jolly Bodies Pappenheimer Bodies (Iron)
Basophilic Stippling SYNONYMS: punctuated basophilia APPEARANCE: Medium-sized, blue-black dots (granules) evenly distributed throughout the RBC KEY FEATURES: –Size of granules: numerous small coarse or fine granules; uniform in size and shape ; 0.5 m in diameter –Cytoplasm: uniformly filled with deep blue or blue-gray dots
Basophilic Stippling
Pappenheimer Bodies SYNONYMS: none APPEARANCE: Small dark blue-purple staining hemoglobin iron granules; seen on Wright stained smear and confirmed with iron (Prussian blue) stain KEY FEATURES: –Size: usually less than 1 m (sometimes <0.5 m) –Shape: blue-purple granules with irregular, sharp edges (not round) –Location: usually found along the periphery of the cell; one or two irregular, small blue- purple-green granules; if present in multiples, they form irregular closely aggregated clusters
Pappenheimer Bodies Wright Stain
Pappenheimer Bodies Iron Stain
Hemoglobin Crystals SYNONYMS: none APPEARANCE: dense staining, angular crystalline forms that vary in shape; may be rectangular, rod-shaped, tetragonal, octahedral (Washington monument, gold bar), spherocytic, rhomboid, or hexagonal KEY FEATURES: –Size: variable since crystals may markedly distort the cell –Shape: a normal disc shape is distorted by the crystal; cytoplasm contains the crystal, which is a precipitate of hemoglobin C or SC –Cytoplasm: often pale or colorless; there is generally a clear area around the crystal
Hemoglobin SC Crystals glove cells
Typical RBC Abnormal Morphology Polychromasia Acanthocyte Teardrop Schistocyte Microcyte Spherocyte Burr Cell Elliptocyte Target Cell Hypochromic
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