[MRI findings of renal cell carcinoma associated with Xp11.2 translocations/TFE3 gene fusions].

Objective: To analyze MRI findings of renal cell carcinoma associated with Xp11.2 translocation-TFE gene fusion(Xp11.2 RCC). Methods: MR imaging features of eleven patients with pathologically-proved Xp11.2 RCC were retrospectively analyzed from December 2008 to December 2015. The following MRI features of the lesions were analyzed in the study: location, maximal diameter, signal intensity, hemorrhage, necrosis, cystic change, enhancement features and metastasis. The data was analyzed by using t test. Results: Four men and seven women (mean age, 35.2 years; age range, 15-49 years) were included. Tumors occurred in the right kidney in 5 cases and the left kidney in 6 cases. On T1 WI tumors showed heterogeneously hypo-intensity and iso-intensity, hyper-intensity in 10 cases, 1 cases, respectively. On T2 WI tumors showed heterogeneously slight hypo-intensity, heterogeneously slight hyper-intensity and hyper-intensity in 6 cases, 4 cases, 1 case, respectively. On DWI tumors showed hyper-intensity and heterogeneously slight hype-intensity in 2 cases, 9 cases, respectively. ADC value of the tumors were statistically significant lower than that of renal cortex(×10-3 mm2 /s)(1.35±0.20 vs 2.09±0.11, P <0.05). Imaging findings were suggestive of hemorrhage( n =4) or necrosis ( n =1) or cystic change ( n =6) or lipid( n =1) in the tumors. On dynamic contrast-enhanced imaging, tumors showed lower signal intensity change (96%±93%, 110%±86% and 103%±46%, respectively) than did renal cortex (285%±109%, 254%±97% and 225%±90%, respectively) ( P <0.05). Tumor capsule showed in 7 cases. Enlarged lymph node was found in renal hilum in one case. Conclusion: MRI findings may show characteristic features of Xp11.2 RCC combined with patients' age and assist in preoperative correct diagnosis.