case_images: PMC10715857_01
case_images: Axial (a), coronal (b), and sagittal (c) view of a contrast-enhanced CT of abdomen which showed a 9 x 5.5 x 3.9 cm smoothly marginated heterogenous hyperdense lesion in the left mid abdomen separate from the adjacent bowel loops (arrows).
case_images: CRIRA2023-3178778.001.jpg
case_images: PMC10715857_01_CRIRA2023-3178778.001.jpg
case_images: fig1
case_images: CT scan with IV contrast (Figure 1) was performed, which revealed a well-defined 9 x 5.5 x 3.9 cm heterogenous mass with a mean attenuation of 50
case_images: Axial T2-weighted image showing a left upper quadrant lesion with heterogenous hyperintense signal (arrow in (a)). Corresponding axial T2-weighted with fat saturation which shows no evidence of fat signal suppression within the lesion (arrow in (b)). Corresponding T1-weighted image with fat saturation showing no signal hyperintensity excluding the presence of methemoglobin (arrow in (c)). Dynamic contrast-enhanced sequences with subtraction technique (d-f) showed faint early arterial enhancement (arrow in (d)) which progressed in the venous phase (arrow in (e)) and continued to increase in signal intensity during equilibrium phase (arrow in (f)).
case_images: CRIRA2023-3178778.002.jpg
case_images: PMC10715857_01_CRIRA2023-3178778.002.jpg
case_images: fig2
case_images: The following day, the abdominal MRI redemonstrated an intraperitoneal mass in the left upper quadrant (Figure 2) without significant change in size.
case_images: Follow-up noncontrast MRI 18 hours after the initial MRI study. Axial T2-weighted image shows an anterior shift in position of the lesion which remains heterogenous with predominantly hyperintense signal (arrow in (a)). There are no new areas of significant signal loss to suggest deoxyhemoglobin formation. Corresponding axial T1 fat sat image shows no retention or layering of contrast from the prior contrast-enhanced MRI exam (arrow in (b)). There remains no evidence of hyperintense signal to suggest methemoglobin formation. Note residual contrast enhancement of the liver, pancreas, and kidneys (asterisks in (b)).
case_images: CRIRA2023-3178778.003.jpg
case_images: PMC10715857_01_CRIRA2023-3178778.003.jpg
case_images: fig3
case_images: The delayed MRI obtained 18 hours after initial MR imaging and 32 hours after initial CT showed no signal evolution of the lesion on the T2-weighted images or evidence of contrast extravasation to suggest active bleeding (Figure 3).
case_images: Histopathological images of the resected tumor. Areas of extensive tumor necrosis (H&E x100) (a). Photomicrograph shows tumor located within omental adipose tissue (H&E x100) (arrows in (b)). Cellular spindle tumor areas with frequent mitoses (highlighted in the circles) (H&E x400) (c). PanTRK immunostain shows diffuse cytoplasmic staining (x400) (d).
case_images: CRIRA2023-3178778.004.jpg
case_images: PMC10715857_01_CRIRA2023-3178778.004.jpg
case_images: fig4
case_images: Microscopy revealed a lobulated cellular tumor with interlacing bundles of monotonous spindle to ovoid cells, loose myxoid areas, extensive necrosis, and focal dystrophic calcifications (Figure 4(a)), involving the lobules of omental fat (Figure 4(b)). Mitoses are frequent, 44 mitoses per 10 high power field (Figure 4(c)). Since the NTRK-rearranged tumors usually show positivity with PanTRK antibodies (Figure 4(d)), the molecular analysis using next-generation sequencing (NGS) was performed.