肾脏嗜酸细胞腺瘤和肾癌的螺旋CT鉴别诊断

Differential diagnosis of renal oncocytoma and carcinoma by spiral CT

目的提高对肾嗜酸性细胞腺瘤螺旋CT表现的认识水平,增加本病诊断的准确性。方法分析经手术病理证实的16例共17个肾嗜酸细胞腺瘤的螺旋CT表现。结果①嗜酸细胞腺瘤和肾癌的CT形态表现比较:16例共17个嗜酸细胞腺瘤中,88.2%(15/17)的肾脏嗜酸细胞腺瘤平扫为密度均匀的肿块,70.6%(12/17)为等密度,所有肿瘤内均未见钙化,增强扫描时52.9%(9/17)不均匀强化,11.8%(2/17)在增强扫描皮髓期表现病灶中央星状瘢痕,其中1例星状瘢痕在肾盂期强化,呈星状高密度。30例早期肾细胞癌平扫时76.7%(23/30)为密度均匀的肿块,70.6%(19/30)为低密度,增强扫描时86.7%呈不均匀强化(26/30),13.3%(4/30)在皮髓期病灶出现中央星状瘢痕,2例出现轮辐状强化,其中1例可同时观察到轮辐状强化及中央瘢痕。②平扫时肾脏嗜酸细胞腺瘤的CT值较肾癌高,P值<0.05。增强扫描各时相二者CT值无明显差异,但是嗜酸细胞腺瘤的增强峰值出现在皮髓期,而肾细胞癌的增强峰值出现在实质期。结论肾脏嗜酸细胞腺瘤与肾癌鉴别诊断很困难,平扫多为等密度、没有包膜、没有钙化、增强扫描的峰值为皮髓期的肿块可提示嗜酸细胞腺瘤,但确诊还需穿刺活检。

Objective To improve the knowledge of renal oncocytoma and increase the accuracy of differential diagnosis of renal oncocytoma from carcinoma. Methods Compared the CT features and the CT attenuation value of 16 patients with 17 renal oncocytomas （ROCs） to 30 renal carcinomas （RCCs） without metastasis. Multi-phase spiral CT was performed in all of these cases which were proven operative pathologically. Results ①The CT features of ROCs and RCCs： at pre-contrast CT 88.2% ROCs and 76.7% RCCs were homogeneous, 70.6% （12/17） ROCs were isodense and 76.7 （19/30） RCCs were hypodense, respectively. Contrast enhanced was inhomogeneouse in 52.9% （9/17） of ROCs and 86.7% （26/30） of RCCs. The hypodense centra steliate scar was detected both in 2/17 ROCs and 4/30 RCCs in corticomedulary phase, the central stellate scar was hyperdense in 1 of 2 ROCs in excretory phase, the others remain hypodense. Spoken wheel-like enhancement was observed in 2/30 RCCs in corticomedulary phase, both spoken-wheel-like enhancement and central stellate scar was found in 1/30 RCCs. No caclification and spoken wheel-like enhancement was detected in 17 ROCs. ②The CT value of ROCs and RCCs： at pre-contrast CT the CT attenuation value of ROCs were higher than that of RCCs, P〈0.05. The CT attenuation value of ROCs and RCCs had no significant deference at contrast enhancement CT scan, but the ROCs showed a peak attenuation value in corticomedulary phase, and the RCCs showed that in nephrographic phase. Conclusion It is difficult to differentiate the ROCs and RCCs preoperation, but CT findings including isodense mass, no calcification and the peak attenuation value in corticomedullary phase can suggest the diagnosis of renal oncocytoma, the final diagnosis needs fine-needle biopsy.