MR imaging features of benign retroperitoneal extra-adrenal paragangliomas

Figures

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  Figure 1. A 49-year-old asymptomatic man with incidentaloma and a histologically proven benign retroperitoneal paraganglioma at the right prevertebral region (between the inferior vena cava and aorta). The transverse and longitudinal diameters of the tumor are 2.61 cm and 3.13 cm, respectively. (A) in axial T2-weighted imaging, the tumor demonstrates high signal intensity and isointensity compared with the gluteal muscles. The intratumoral cystic areas exhibit higher signal intensity. (B) In axial DWI, the tumor exhibits ring-shaped high signal intensity. (C–E) T1-weighted imaging (in-phase, out-phase and pre-scanned imaging, respectively); the signal of the tumor is slightly lower than that of the gluteal muscle. (F) In contrast T1-weighted imaging during the arterial phase, the tumor is clearly enhanced and non-homogeneous. (G) In coronal T1-weighted imaging during the delay phase, the tumor is clearly enhanced and non-homogeneous. (H) ADC imaging; the mean ADC value of the ROI of the tumor is 0.00147 mm2/s.

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  Figure 2. A 47-year-old man with incidentaloma and a histologically proven benign retroperitoneal paraganglioma at the right prevertebral region (among the inferior vena cava, pars horizontalis duodeni and aorta). The transverse and longitudinal diameters of the tumor are 3.92 cm and 3.72 cm, respectively. (A) In axial T2-weighted imaging, the tumor demonstrates high signal intensity and isointensity compared with the gluteal muscles. (B) In axial DWI, the tumor appears with nodular high signal intensity compared with the spleen. (C–E) T1-weighted images (in-phase, out-phase and pre-scanned imaging, respectively); the signal of the tumor is slightly lower than that of the gluteal muscle. (F) In contrast T1WI during the arterial phase, the tumor is clearly enhanced and non-homogeneously ring-shaped. The center exhibits no enhancement of the necrotic area. (G) In coronal T1WI during the delay phase, the tumor shows a continuous and non-homogeneous signal increase. (H) ADC imaging; the mean ADC value of the ROI of the tumor is 0.00180 mm2/s.

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  Figure 3. A 60-year-old man with hypertension, positive VMA/24 h and a histologically proven benign retroperitoneal paraganglioma at the right prevertebral region (between the inferior vena cava and aorta). The transverse and longitudinal diameters of the tumor are 2.89 cm and 4.43 cm, respectively. (A) In axial T2WI, the tumor exhibits high signal intensity and isointensity compared with the gluteal muscles. The intratumoral septa exhibit low signal intensity. The tumor capsule is shown in T2WI. (B) In axial DWI, the tumor appears nodular with ring-shaped high signal intensity. (C–E) In T1WI (in-phase, out-phase and pre-scanned imaging, respectively), the partial signal of the tumor is higher than that of the gluteal muscle, and most of the signal of the tumor is of slightly lower intensity than that of gluteal muscle. (F) In contrast T1WI during the arterial phase, the tumor is clearly enhanced with a non-homogeneous ring. The center exhibits no enhancement of the necrotic area and cysts. (G) In coronal T1WI during the delay phase, the tumor exhibits a continuous and non-homogeneous signal increase. The intratumoral septa show a continuous signal increase. (H) ADC imaging; the mean ADC…

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  Figure 4. A 53-year-old woman with dizziness and hypertension and a histologically proven benign retroperitoneal paraganglioma at the left paravertebral region (adjacent to the left adrenal gland). The transverse and longitudinal diameters of the tumor are 8.04 cm and 9.71 cm, respectively. (A) In axial T2WI, the tumor exhibits mixed signal intensity, including high signal intensity, slightly high signal intensity, and isointensity, compared with the gluteal muscles. The signs of fluid-fluid levels can be seen. The intratumoral septa exhibit low signal intensity. (B) In axial DWI, the tumor appears with a ring of high signal intensity. (C–E) In T1WI (in-phase, out-phase and pre-scanned imaging, respectively), the signal of the tumor is slightly lower than that of the gluteal muscle in in-phase imaging and pre-scanned imaging, and exhibits a linear and sheet-like high signal in out-phase imaging. (F) In contrast T1WI during the arterial phase, the tumor exhibits slight and non-homogeneous enhancement. The center exhibits no enhancement of the necrotic area. (G) In coronal T1WI during the delay phase, the tumor is slightly enhanced. (H) ADC imaging; the mean ADC value of the ROI of the tumor…