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case_images: Echocardiography and chest contrast-enhanced CT demonstrating a massive mass (black arrow) and pericardial effusion (star). (A,B) Echocardiography shows a mass in the pericardium with a small amount of blood flow signals. (C-E) CT reveals an irregular, heterogeneously enhancing mass between pericardium and diaphragm with massive pericardial effusion. (F) Axial contrast-enhanced CT shows enlarged enhancing lymph nodes in the right cardio-diaphragmatic angle (red arrow).
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case_images: F1
case_images: The resting electrocardiogram indicated sinus rhythm and ST-segment elevation (Supplementary Figure S1). The TTE revealed a heterogeneous isoechoic pericardial mass with massive pericardial effusion (Figure 1A). Color Doppler flow imaging demonstrated minimal blood flow signals along the margins of the mass (Figure 1B). The CT scan revealed a 6.5 cm x 7.8 cm x 6.3 cm irregular mass between the pericardium and diaphragm and significant pericardial effusion (up to 40 mm) (Figures 1C-E). Additionally, a 1.0 cm enlarged lymph node was detected in the right cardio-diaphragmatic angle (Figure 1F).
case_images: FDG-PET reveals hypermetabolic activity located between the pericardium and diaphragm, with a standard uptake value (SUVmax) ranging from 5.4-15.9, and no abnormal lesions are found in other parts of the body. FDG-PET, Fluorine-18 fluorodeoxyglucose positron emission tomography.
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case_images: F2
case_images: The PET-CT scan revealed hypermetabolic activity located between the pericardium and diaphragm, with a standard uptake value (SUVmax) ranging from 5.4 to 15.9 (Figure 2). Despite the normal LV ejection fraction but elevated BNP, tissue tracking technology was used to conduct myocardial strain analysis (Supplementary Figure S2).
case_images: Cardiac MRI shows mass tissue characterization. (A) Cine imaging: heterogeneously hyperintense mass (white arrow) and large pericardial effusion (star). (B) Precontrast T1WI: slightly hypointense mass. (C) Postcontrast T1WI: non-enhanced core within mass, surrounded by slightly heterogeneous enhancement (black arrow). (D) Postcontrast T1WI: enlarged enhanced lymph nodes (red arrow). (E,F) Diffusion MRI: bright mass on DWI and dark on ADC (yellow arrow).
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case_images: F3
case_images: Specifically, in accordance with CT, CMR showed an irregular defined mass between the pericardium and diaphragm, adjoining with enlarged lymph nodes in the right cardio-diaphragmatic angle and massive pericardial effusion (Figure 3). T1w-imaging and a heterogeneously hyperintense appearance on T2w-imaging of the mass (Figures 3A,B, 4A,B). The presence of heterogeneously strongly elevated T1 (1,700-2,500 ms) and T2 values (120-172 ms) within the mass was also documented using T1 and T2 mapping images (Figures 4D,E). On late gadolinium enhancement (LGE) imaging, there was no LGE core within the mass, surrounded by slightly heterogeneously high signal enhancement (Figures 3C,D, 4C). Diffusion MRI revealed that the mass was homogeneously bright on diffusion weighted imaging (DWI) and dark on apparent diffusion coefficient (ADC) (Figures 3E,F), suggestive of reduced diffusivity possibly owing to hypercellularity. In addition, a CT-guided percutaneous needle biopsy was conducted, and subsequently, histopathological analysis of the tissue sample supported the diagnosis of pericardial sclerosing rhabdomyosarcoma (RMS) (Supplementary Figure S3).
case_images: Representative magnetic resonance images of the basal, mid, and apical short-axis slices. (A) Dark-blood T1-weighted images show isointense mass. (B) Dark-blood T2-weighted images show strongly hyperintense mass. (C) Late gadolinium enhancement sequences reveal that there is peripheral heterogeneous uptake and a spared central core. (D) Native T1 mapping depicts evidently elevated T1 values in the mass. (E) T2 mapping depicts evidently elevated T2 values in the mass.
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case_images: F4
case_images: T1w-imaging and a heterogeneously hyperintense appearance on T2w-imaging of the mass (Figures 3A,B, 4A,B). The presence of heterogeneously strongly elevated T1 (1,700-2,500 ms) and T2 values (120-172 ms) within the mass was also documented using T1 and T2 mapping images (Figures 4D,E). On late gadolinium enhancement (LGE) imaging, there was no LGE core within the mass, surrounded by slightly heterogeneously high signal enhancement (Figures 3C,D, 4C). However, during the eight-month follow-up after treatment, both the mass and lymph nodes in the right cardio-diaphragmatic angle showed modest enlargement (Supplementary Figure S4).