Magnetic Resonance Imaging Features of a Juxtaglomerular Cell Tumor

Abstract

Objective: To retrospectively determine whether magnetic resonance imaging (MRI) findings can help differentiate a juxtaglomerular cell tumor (JCT) from clear cell renal cell carcinoma (ccRCC).

Materials and methods: Eight patients with JCTs and 24 patients with pathologically proven ccRCC were included for image analysis. All patients underwent unenhanced MRI and dynamic contrast-enhanced MRI. Fat-suppressed T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), in- and opposed-phase imaging, and fat-suppressed preliver acquisitions with volume acceleration sequences were performed before enhancement. After the administration of contrast, dynamic imaging was performed in the corticomedullary, nephrographic, and excretory phases. Student's t-test, t'-test, Chi-square test, and nonparametric Kruskal-Wallis H-test were used to determine the significance of the difference between the two groups. The sensitivity and specificity of the MRI findings were calculated.

Results: In patients with a JCT, a cystic part of the lesion of <10%, isointensity or mild hyperintensity on T2WI, heterogeneous hyperintensity on DWI, less signal drop (<10%) in in- and opposed-phase imaging, and a degree of enhancement <200% in the corticomedullary phase showed statistically significant differences compared with those of ccRCC (P < 0.05). After combining a lower apparent diffusion coefficient (ADC) value (heterogeneous hyperintensity) on DWI and a degree of enhancement <200% in the corticomedullary phase using a parallel test, the sensitivity and specificity were 90.9% and 91.7%, respectively.

Conclusions: Isointensity or mild hyperintensity on T2WI, a lower ADC value (heterogeneous hyperintensity) on DWI, and a degree of enhancement <200% in the corticomedullary phase are the major MRI findings for JCTs, combined with relative clinical manifestations and excluding other renal masses. A main solid tumor, less signal drop (<10%) in in- and opposed-phase imaging, and a less-washout pattern of <10% in the delayed phase are secondary MRI findings for JCTs.

Keywords: Clear cell renal cell carcinoma; combination; juxtaglomerular cell tumor; magnetic resonance imaging findings.

Figure 1

28-year-old man with Grade 3 hypertension for 7 years with a solid tumor on the left kidney and the pathological diagnosis was juxtaglomerular cell tumor after surgery. (a) On T2-weighted image, the lesion (short arrow) shows isointensity to mild hyperintensity with a low-signal capsule (long arrow). (b) On diffusion-weighted image, the lesion (short arrow) indicates heterogeneous hyperintensity compared with the cortex signal and the low-signal capsule (long arrow) does not indicate clearly. (c) On the corticomedullary phase image, the lesion (short arrow) shows mild enhancement. (d) On the nephrographic phase image, the lesion (short arrow) shows a mild persistent enhancement.

Figure 2

23-year-old man with Grade 3 hypertension for 4 years with a solid and cystic tumor near the right renal pelvis and the pathological diagnosis was juxtaglomerular cell tumor after surgery. (a) On T2-weighted image, the lesion shows heterogeneous hyperintensity without a low-signal capsule, the solid part of the lesion (short arrow) shows heterogeneous hyperintensity, the cystic part of the lesion (long arrow) shows hyperintensity. (b) On diffusion-weighted image, the solid part of the lesion (short arrow) indicates heterogeneous hyperintensity, the cystic part of the lesion (long arrow) shows iso to mild hyperintensity. (c) On the corticomedullary phase image, the solid part of the lesion indicates a mild enhancement (short arrow). (d) On the nephrographic phase image, the solid part of the lesion (short arrow) shows a slight persistent enhancement.

Figure 3

(a) The receiver operator characteristic curve of apparent diffusion coefficient. (b) Enhanced times in corticomedullary phase.

Figure 4

(a) The enhanced times in three phases between juxtaglomerular cell tumor and clear cell renal cell carcinoma. (b) The enhanced times of trend in three phases between juxtaglomerular cell tumor and clear cell renal cell carcinoma. Cor: Corticomedullary phase times, Neph: Nephrographic phase times, Exc: Excretory phase times.