肾嫌色细胞癌的磁共振表现

Pathological correlation of dynamic magnetic resonance findings for chromophobe cell renal carcinoma

目的 分析肾嫌色细胞癌的MR表现和血液动力学特征及其与病理的关系,以提高肾嫌色细胞癌诊断准确性.方法 收集南通大学附属医院和复旦大学附属中山医院1999年7月至2009年3月经手术病理证实的肾嫌色细胞癌12例,术前经MR SE-T1WI、FSE-T2WI和扰相梯度回波动态增强成像,根据肾脏皮质及肿瘤强化百分比绘制动态增强曲线.回顾MR扫描结果并和手术病理作回顾性对照分析.结果 12例嫌色细胞癌中,肿瘤位于肾皮质1例,肾髓质9例,难以判定2例.肿瘤呈球形9例,椭圆形3例,肿瘤境界清楚.MR信号均匀,T1WI、T2WI呈中等信号,所有病灶可见假包膜形成的低信号环,2例可见中央瘢痕.双期增强肿瘤皮髓交界期平均强化百分比为120.3%,同期肾脏皮质平均强化百分比215.4% 实质期肿瘤平均强化百分比为173.7%,同期肾脏皮质平均强化百分比为249.1%.结论 嫌色细胞癌是以肾髓质为中心的中等信号类球形肿瘤,信号均匀,假包膜明显,部分病例可见中央瘢痕,皮髓交界期呈中等强化,实质期多轻度持续强化,均低于肾脏皮质强化,MR诊断价值明显.

Objective To explore the dynamic magnetic resonance（MR）imaging findings of chromophobe cell renal carcinoma and evaluate its pathological correlation.Methods Twelve cases with chromophobe cell renal carcinoma confirmed by surgical pathology underwent MR plain scanning and dynamic enhancement scanning before operation.And the MR data were reviewed and analyzed retrospectively in comparison with surgical and pathological results.Results Twelve lesions were located in right kidney（n =9）and left kidney（n =3）with a mean tumor diameter of 7.3 cm（range：3.2-12.6 cm）.They were located in renal cortex（n = 1）, renal medulla（n = 9）and the middle of cortex and medulla with a relatively normal renal shape.Nine lesions appeared global and 3 elliptic in shape.Well-defined margin was showed in 12 lesions and a thin capsule was observed in all lesions.The tumor presented a low to middle homogeneous signal intensity on T1 WI and intermediates homogeneous signal intensity on fat saturated FSE-T2WI with a hypointense thin capsule and a hyperintense central scar.A mild-to-middle degree of tumor enhancement in cortical phase（tumor SI change 120.3% with a standard deviation of 84.3 and a median of 115.2%）was slightly lower, isointense or slightly higher than renal medulla.And obvious enhancement in portal venous phase（tumor SI change 173.7% with a standard deviation of 92.4 and a median of 171.5%）was lower than renal medulla.Conclusion Chromophobe cell renal carcinoma typically forms large and wellcircumscribed global solid masses in renal medulla.With a relatively normal renal shape and a thin capsule,it shows intermediate homogeneous signal intensity on T1WI and T2WI.And a middle degree enhancement with central stellate scar is found in some patients.