Imaging features of renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusions: comparison with chromophobe renal cell carcinoma / 中华放射学杂志

ABSTRACT

Objective:To compare the imaging features of renal cell carcinoma (RCC) associated with Xp11.2 translocation/TFE3 gene fusion (Xp11.2 RCC) with chromophobe RCC.Methods:From November 2016 to January 2020, 28 patients with Xp11.2 RCC and 28 patients with chromophobe RCC confirmed by pathology were retrospectively analyzed in Peking University First Hospital. All 23 patients underwent preoperative CT examination, and 5 patients underwent routine MRI in each group. The clinical and imaging features were observed and recorded. The CT features including side, location, size, boundary, shape, uniform density, composition (solid, cystic-solid, cystic), hemorrhage, calcification, lymph node metastasis of the lesions and distant metastasis were observed, and the CT value of the solid part of the tumor at each stage was measured. On MRI images, the signal of the lesion in each sequence and enhancement mode were observed. The differences in clinical and imaging characteristics between the 2 groups were compared using independent samples t test or χ 2 test. Results:The Xp11.2 RCC more frequently affected young [(27±10) years] patients, while chromophobe RCC more frequently involved middle-aged [(37±7) years] patients asymptomatically, and the difference was statistically significant ( t=-4.99, P<0.001). The lesion size of Xp11.2 RCC [(5.4±2.2) cm] were significantly smaller than that of chromophobe RCC [(6.9±1.8) cm] ( t=-2.93, P=0.005). There were significant differences in the density and composition of lesions between Xp11.2 RCC and chromophobe RCC (χ 2=4.60, 18.67, P=0.032,<0.001). There were no significant differences in the side, location, boundary, shape, hemorrhage, calcification, fat, lymph node metastasis and distant metastasis between the 2 kind of lesions (all P>0.05). The CT values of solid components in Xp11.2 RCC in cortico-medullary phase and delayed phase were higher than those in chromophobe RCC, and the difference were statistically significant ( t=11.80, 20.15, both P<0.001). Five cases of Xp11.2 RCC showed iso- or slightly hyperintense signal on T 1WI and slightly hypointense signal on T 2WI. Two cases showed delayed enhancement after enhancement, and 3 cases showed a slight decrease in delayed phase enhancement. Conclusion:Compared with chromophobe RCC, Xp11.2 RCC has certain characteristics in imaging manifestations (lesion size, density uniformity, composition, CT value of post-enhanced cortico-medullary phase and delayed phase). Imaging manifestations combining the clinical manifestations (age of onset) are helpful for preoperative diagnosis of Xp11.2 RCC.