BCP-21 Blood Cell Identification Graded Case History The patient is a 37-year-old female with a history of multiple sickle cell crises. She now presents with avascular necrosis of the left hip. Laboratory data includes: WBC = 12.8 x 10 9 /L; RBC = 3.05 x 10 12 /L; HGB = 8.7 g/dl; HCT = 26.4%; MCV = 86.4 fl; MCHC = 33.0 g/dl; RDW = 16.9; and PLT = 331 x 10 9 /L. Referees Participants Target cell (codocyte) 70 95.9 5273 99.7 Good Neutrophil, giant band or giant metamyelocyte Howell Jolly body (Wright stain) Pappenheimer bodies(iron stain) 1 1.4 1 <0.1 Unacceptable 1 1.4 1 <0.1 Unacceptable 1 1.4 - - Unacceptable The red blood cell identified by the arrow is a target cell (codocyte), as correctly identified by 95.9% of referees and 99.7% of participants. Target cells are red cells with a bull s eye appearance, resulting from a greater-thannormal surface membrane-to-volume ratio. The cells exhibit a central hemoglobinized region with a surrounding area of pallor, which in turn is surrounded by a peripheral hemoglobinized zone. Target cells are seen in a number of conditions, including thalassemias, liver disease, and some hemoglobinopathies. In the central region of this smear, two misshapen, darkly stained red cells are present; these cells contain hemoglobin C crystals in this patient with Hb SC disease and are often referred to as SC poikilocytes. 2
BCP-22 Blood Cell Identification Graded Platelet, normal 72 98.6 5204 98.4 Good Platelet, hypogranular 1 1.4 64 1.2 Unacceptable The blood component identified by the arrow is a platelet, as correctly identified by 98.6% of referees and 98.4% of participants. Platelets are small, blue-gray fragments (1.5 to 3 μm in diameter) of megakaryocytic cytoplasm. Fine, purple-red granules are aggregated at the center or dispersed throughout the cytoplasm. Some platelets have long cytoplasmic projections or ruffled margins. Platelets are typically single but may form aggregates. Additionally, in the center of the field is a medium-sized normal lymphocyte. 3
BCP-23 Blood Cell Identification Graded Monocyte 73 100.0 5209 98.4 Good The blood cell identified by the arrow is a monocyte, as correctly identified by 100.0% of referees and 98.4% of participants. Monocytes typically have abundant gray to gray-blue (ground-glass appearance) cytoplasm, which can contain fine, evenly distributed, azurophilic granules or vacuoles. They are slightly larger (12 to 20 μm in diameter) as compared to mature neutrophils (10 to 15 μm in diameter). Their nuclear-to-cytoplasmic ratio is 4:1 to 2:1. Their nuclei are usually indented, often resembling a three-pointed hat, but can also be folded or bandlike. Their chromatin is condensed, but less densely than that of a neutrophil or lymphocyte. Nucleoli are generally absent, but occasional monocytes may contain a small, inconspicuous nucleolus. The majority of monocytes have smooth edges, but some have pseudopod-like cytoplasmic extensions, as in the monocyte shown here. Of interest, just above and to the right of the monocyte is a giant platelet. 4
BCP-24 Blood Cell Identification Graded Lymphocyte 72 98.6 5256 99.4 Good Lymphocyte, large granular 1 1.4 4 0.1 Unacceptable The blood cell identified by the arrow is a lymphocyte, as correctly identified by 98.6% of referees and 99.4% of participants. Lymphocytes are small, round to ovoid cells (7 to 15 μm in diameter), and can exhibit a range of normal morphology. Their N:C ratio can vary, sometimes having a moderate amount of cytoplasm (N:C = 2:1) to a scant amount (N:C = 5:1). Most lymphocytes have round to oval nuclei that may be slightly indented or notched. The chromatin is diffusely dense or coarse and clumped. Nucleoli, if present, are small and inconspicuous. 5
BCP-25 Blood Cell Identification Graded Sickle cell (drepanocyte) 70 97.2 5087 96.2 Good Fragmented red cell 1 1.4 124 2.3 Unacceptable (schistocyte, helmet cell, keratocyte, triangular cell) Hemoglobin C crystal 1 1.4 56 1.1 Unacceptable The red blood cell identified by the arrow is a sickle cell (drepanocyte), as correctly identified by 97.2% of referees and 96.2% of participants. Characteristic sickle cells of sickle cell disease (homozygous Hb S) appear as a thin crescent with two pointed ends and lack central pallor, while sickle cells associated with SC disease, as in the present case, are often somewhat more plump or have a boat shaped appearance. Polymerized hemoglobin S can lead to a variety of red cell morphologies, including crescent-shaped, boat-shaped, filament-shaped, holly-leaf form, or envelope cells. Sickle cells may be seen particularly in the absence of splenic function or after splenectomy in patients with sickle cell anemia, hemoglobin SC disease, SD disease, and S-beta-thalassemia. Ria Vergara-Lluri, MD and Joan Etzell, MD Hematology and Clinical Microscopy Resource Committee 6
BCP-26 Blood Cell Identification Ungraded Case History The patient is a 24-year-old female presenting with a 3 week history of progressive abdominal distention, secondary to massive splenomegaly. Laboratory data includes: WBC = 430 x 10 9 /L; HGB = 7.7 g/dl; MCV = 86.4 fl; PLT = 637 x 10 9 /L; RDW = 17.1, and elevated LDH = 771 U/L (140-280 U/L). BCR-ABL1 is positive. Referees Participants Blast cell 66 93.0 4632 90.3 Educational Myeloblast with Auer rod 1 1.4 188 3.7 Educational Immature or abnormal cell, 1 1.4 103 2.0 Educational would refer for identification Neutrophil, promyelocyte 1 1.4 49 1.0 Educational Neutrophil promyelocyte, abnormal with/without Auer rod(s) Lymphocyte, reactive (to include plasmacytoid and immunoblastic forms) Monocyte, immature (promonocyte, monoblast) 1 1.4 19 0.4 Educational 1 1.4 26 0.5 Educational - - 69 1.4 Educational The cell identified by the arrow is a blast cell as correctly identified by 93.0% of referees and 90.3% of participants. The cell is large and has a high nuclear-tocytoplasmic ratio. The nucleus is round with finely reticulated chromatin and prominent nucleoli. The cytoplasm is basophilic and lacks the primary granules found in promyelocytes. The morphologic appearance of the arrowed cell is typical of a myeloblast; however, in the absence of Auer rods, it is not possible to definitively identify the lineage of a blast cell using routine Wright-Giemsa staining. 7
BCP-27 Blood Cell Identification Ungraded Basophil, any stage 69 97.2 4977 96.9 Educational Eosinophil, any stage 1 1.4 69 1.3 Educational Lymphocyte 1 1.4 - - Educational Neutrophil, toxic (to include toxic granulation and/or Döhle bodies, and/or toxic vacuolization) - - 56 1.1 Educational The cell identified by the arrow is a basophil as correctly identified by 97.2% of referees and 96.9% of participants. Basophils characteristically have large, coarse granules that stain blue-black or sometimes purple to red in Wright-stained smears. The granules are unevenly distributed and typically overlay the nucleus. Basophils are invariably increased in chronic myelogenous leukemia. Non-neoplastic conditions associated with increased basophils include hypersensitivity reactions, hypothyroidism, and chronic renal disease. 8
BCP-28 Blood Cell Identification Ungraded Neutrophil, metamyelocyte 62 87.3 4469 87.1 Educational Neutrophil, segmented or 4 5.6 93 1.8 Educational band Monocyte 4 5.6 255 5.0 Educational Neutrophil, giant band or giant metamyelocyte 1 1.4 106 2.1 Educational The cells identified by the arrows are metamyelocytes as correctly identified by 87.3% of referees and 87.1% of participants. Metamyelocytes are neutrophil precursors with abundant cytoplasm, an indented nucleus, and clumped nuclear chromatin. The cytoplasm is amphophilic and contains many fine specific (secondary) granules and rare azurophilic (primary) granules. The nucleus of a metamyelocyte has a shallow indentation that is less than half the diameter of the nucleus. This feature is used to distinguish metamyelocytes from neutrophilic bands, which have nuclear indentations greater than half the diameter of the nucleus. 9
BCP-29 Blood Cell Identification Ungraded Referees BCP Participants Performance Neutrophil, myelocyte 68 95.8 4750 92.6 Educational Neutrophil, promyelocyte 1 1.4 84 1.6 Educational Lymphocyte 1 1.4 10 0.2 Educational Monocyte, immature 1 1.4 43 0.8 Educational (promonocyte, monoblast) Immature or abnormal cell, - - 56 1.1 Educational would refer for identification Lymphocyte, large granular - - 48 0.9 Educational The cells identified by the arrows are myelocytes as correctly identified by 95.8% of referees and 92.6% of participants. Myelocytes are smaller than blasts or promyelocytes and have a lower nuclear-to-cytoplasmic ratio of 2:1 to 1:1. The cytoplasm is amphophilic and contains both azurophilic (primary) and specific (secondary) granules. The nucleus is round to oval, often eccentrically located, and may be flattened on one side. The nucleus lacks the indentation seen in metamyelocytes. Some chromatin clumping is apparent, and nucleoli are absent. In chronic myelogenous leukemia, there is often a disproportionate increase in myelocytes, with myelocytes outnumbering metamyelocytes and band forms in the peripheral blood. 10
BCP-30 Blood Cell Identification Ungraded Neutrophil, promyelocyte 65 92.9 4548 88.6 Educational Neutrophil promyelocyte, 2 2.9 223 4.4 Educational abnormal with/without Auer rod(s) Blast cell 1 1.4 127 2.5 Educational Lymphocyte, reactive (to include plasmacytoid and immunoblastic forms) Immature or abnormal cell, would refer for identification 1 1.4 - - Educational - - 80 1.6 Educational The cell identified by the arrow is a normal promyelocyte as correctly identified by 92.9% of referees and 88.6% of participants. Compared to myeloblasts, promyelocytes are generally slightly larger cells and have a lower nuclear-to-cytoplasmic ratio. The nucleus is round to oval with fine chromatin and distinct nucleoli, similar to a blast cell nucleus. The cytoplasm is basophilic and contains multiple distinct azurophilic (primary) granules. Development of distinct primary granules is the main feature that distinguishes a promyelocyte from a blast. Promyelocytes are normally confined to bone marrow, but can be seen in the peripheral blood in pathologic conditions. Kyle T. Bradley, MD Hematology and Clinical Microscopy Resource Committee 11