PMC7525322_01
Features of leukemia cells ((a) gross appearance of lard-like blood clot in the aorta; (b) Giemsa-stained cytology of leukemia cells; (c) hematoxylin and eosin- (H&E-) stained histology of the bone marrow; immunostaining for MPO (d), CD34 (e), and CD117 (f)). The coagulated leukemia cells form white-colored elastic clots in the vascular space. The leukemic blasts in pleural effusion show high nuclear/cytoplasmic ratio and lack azurophilic granules. The bone marrow reveals 100% cellularity occasionally with megakaryocytic differentiation. The blasts in the bone marrow are immunoreactive for MPO, CD34, and CD117 (c-kit).
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fig1
CD34 and CD117 (c-kit). CD3, CD10, CD20, CD79a, and terminal deoxynucleotidyl transferase were negative.  Figure 1 demonstrates lard-like leukemic thrombosis in the aorta, leukemic blasts in the pericardial space, and bone marrow histology.  Figure 2 illustrates a high-powered microscopic view of blood clot in the atrial lumen. MPO-positive and CD42b/CD61-negative, while MPO-negative megakaryocytic cells strongly expressed CD42b/CD61, as illustrated in Figure 3. Morphological differentiation toward CD42b/CD61-positive megakaryocytes was also observed in the bone marrow (see Figure 1), lymph nodes, and liver.  Figure 4 demonstrates diffuse infiltration of MPO-positive and CD61-negative blastic cells in the lymph node parenchyma and CD61-positive and MPO-negative megakaryocytic differentiation mainly in the sinus.
Histopathological appearance of blood clot in the atrium ((a) H&E; immunostaining for MPO (b), CD42b (c), and CD61 (d)). Most of the small-sized blastic cells in the blood express MPO. CD42b and CD61 label platelets among the blasts, but the blasts are devoid of expression of the megakaryocytic markers.
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fig2
CD34 and CD117 (c-kit). CD3, CD10, CD20, CD79a, and terminal deoxynucleotidyl transferase were negative.  Figure 1 demonstrates lard-like leukemic thrombosis in the aorta, leukemic blasts in the pericardial space, and bone marrow histology.  Figure 2 illustrates a high-powered microscopic view of blood clot in the atrial lumen.
The heart involved by leukemic cells ((a) cut surface of the heart after formalin fixation; (b) H&E, inset: high-powered view; (c) MPO; (d) CD61). Grossly, the subendocardial myocardium circumferentially appears dark-colored. Microscopically, the MPO-positive leukemic blasts invade both the myocardium and endocardium. CD61-positive megakaryocytic cells are distributed in the endocardium. The inset demonstrates high-powered H&E morphology of a subendocardial located megakaryocyte. The infiltrating blasts replace the cardiomyocytes. Neither granulation tissue reaction nor fibrosis is seen in the involved myometrium.
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fig3
MPO-positive and CD42b/CD61-negative, while MPO-negative megakaryocytic cells strongly expressed CD42b/CD61, as illustrated in Figure 3. Morphological differentiation toward CD42b/CD61-positive megakaryocytes was also observed in the bone marrow (see Figure 1), lymph nodes, and liver.  Figure 4 demonstrates diffuse infiltration of MPO-positive and CD61-negative blastic cells in the lymph node parenchyma and CD61-positive and MPO-negative megakaryocytic differentiation mainly in the sinus.
Lymph node histology ((a) H&E, (b) MPO, and (c) CD61). The nodal parenchyma is diffusely infiltrated by MPO-positive leukemic blasts. CD61-positive megakaryocytic differentiation is observed mainly in the sinus. The small-sized blasts lack expression of CD61.
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fig4
MPO-positive and CD42b/CD61-negative, while MPO-negative megakaryocytic cells strongly expressed CD42b/CD61, as illustrated in Figure 3. Morphological differentiation toward CD42b/CD61-positive megakaryocytes was also observed in the bone marrow (see Figure 1), lymph nodes, and liver.  Figure 4 demonstrates diffuse infiltration of MPO-positive and CD61-negative blastic cells in the lymph node parenchyma and CD61-positive and MPO-negative megakaryocytic differentiation mainly in the sinus.