case_images: PMC9980342_01
case_images: Chest computed tomography on admission. (A) Lung window shows a mass shadow in the lower lobe of the left lung. (B) Mediastinal window shows pericardial effusion.
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case_images: Subsequently, she was referred to our hospital due to a worsening pericardial effusion on computed tomography (CT) scan ( Figure 1 ).
case_images: Changes in electrocardiographic waveforms during hospitalization. The admission electrocardiogram showed (A) sinus tachycardia and low-voltage QRS complexes. (B) Negative T waves appeared on electrocardiogram 27 days after admission, and (C) monomorphic VT appeared 5 days later. Eight days after the start of methylprednisolone administration, (D) negative T waves remained but ST-segment elevation was no longer present. Pre-death electrocardiogram showed (E) R-on-T phenomenon triggered polymorphic VT. QT/QTc intervals: (A) 313/443 ms, (B) 395/507 ms, (C) 433/572 ms, (D) 408/482 ms, (E) 400/408 ms.
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case_images: Electrocardiogram showed sinus tachycardia and low-voltage QRS complexes ( Figure 2A ), while transthoracic echocardiography (TTE) revealed pericardial effusion. Twenty-seven days after admission, blood tests showed elevated CK, CK-MB and troponin T, and a negative T wave appeared on electrocardiogram ( Figure 2B ). An electrocardiogram showed monomorphic VT ( Figure 2C ). Eight days after the start of methylprednisolone administration, negative T waves remained on electrocardiogram, but ST-segment elevation was no longer present ( Figure 2D ); therefore, she was considered to have passed the acute stage and amiodarone administration was terminated. Twelve days after the start of methylprednisolone administration, R-on-T phenomenon triggered polymorphic VT ( Figure 2E ).
case_images: Cardiac biomarkers and electrolytes in blood tests after admission. CK and CK-MB decreased initially after methylprednisolone administration, and troponin T and NT-proBNP decreased later. Electrolytes values at the first occurrence of VT were K 4.1 mEq/L, Ca 9.1 mg/dL, Mg 1.8 mg/dL, and at the second occurrence of VT were K 4.7 mEq/L, Ca 8.9 mg/dL, Mg 2.0 mg/dL. Drugs that induce VT are not used.
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case_images: The following day, CK and CK-MB decreased on blood test ( Figure 3 ) and ventricular tachycardia disappeared on electrocardiogram.
case_images: Histological findings of endocardial biopsy. Histological findings of the myocardium showed (A) an infiltrate of inflammatory cells predominantly composed of lymphocytes by hematoxylin-eosin (HE) staining and (B) granulation fibrosis of the stroma by Masson's trichrome (MT) staining. Immunostaining of the tissue showed (C) CD3-positive T cells infiltrated more than CD20-positive B cells. CD8-positive T lymphocytes infiltrated more than CD4-positive T lymphocytes. Infiltration of CD68-positive macrophages and CD138-positive plasma cells was also observed. (HE x200, MT x200 and CD3/CD4/CD8/CD20/CD68/CD138 immunostaining x200).
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case_images: Myocardial tissue collected at the EMB showed an infiltrate of inflammatory cells predominantly composed of lymphocytes ( Figure 4A ) and granulation fibrosis of the stroma ( Figure 4B ). Immunostaining of the tissue showed an inflammatory cell infiltrate predominantly composed of CD8-positive T lymphocytes ( Figure 4C ).