Differentiation of subtypes of renal cell carcinoma with contrast-enhanced ultrasonography

Abstract

We aimed to assess the difference of enhancement patterns among the three RCC subtypes with contrast-enhanced ultrasound (CEUS). Two hundreds cases of pathologically proved clear cell renal cell carcinomas (ccRCC), 58 papillary renal cell carcinomas (pRCC) and 51 chromophobe renal cell carcinomas (chRCC) underwent preoperative conventional ultrasound and CEUS. The wash-in and wash-out pattern, peak enhancement degree and homogeneity, and the presence of pseudocapsule were evaluated by two blinded observers respectively. The interreader agreement in the characterization of CEUS features between two observers was good (κ = 0.649-0.775). Compared with pRCCs and chRCCs, ccRCCs demonstrated higher frequency of simultaneous wash-in pattern, hyperenhancement and heterogeneity with necrotic areas. Most pRCCs and chRCCs manifested hypoenhancement, homogeneity, fast wash-out and presence of pseudocapsule. The only difference we obtained between pRCC and chRCC was the wash-in pattern, with slow wash-in in pRCC and simultaneous wash-in in chRCC. In small lesions with long diameter≤3 cm, the majority of the three subtypes of RCC showed homogeneous enhancement and there was no difference among them. CEUS was a useful method to preoperatively differentiate the ccRCC from non-ccRCC subtypes. There were no distinguishing features identifid on CEUS that allowed reliable differentiation of pRCC from chRCC.

The independent indicators for differentiating renal cell carcinoma from renal angiomyolipoma by contrast-enhanced ultrasound

“…Xu et al [11] found that heterogeneous enhancement was a major CEUS characteristic regardless of the subtype of RCC. However, the results of Jiang et al [12] and Xue et al [13] showed that for tumors≤3 cm, homogeneous enhancement was more frequently seen on CEUS, regardless of the subtype enhancement.…”

“…Compared with the normal renal parenchyma, RCCs often exhibit fast wash out, while AMLs more often show slow wash out [24]. Xue et al [13] assessed the difference of enhancement patterns among the three RCC subtypes with CEUS, their results demonstrated that most RCCs were fast wash out with the percentage of 47.5(95/200), 89.7(52/58), 76.5(39/51) for clear cell RCCs, papillary RCCs, chromophobe RCCs, respectively. Our results showed that 56.0% (84/150) RCCs exhibited fast wash out.…”

“…This may be related to the size of the tumors included in this study. Moreover, Jiang et al [12], Xue et al [13] and Xu et al [27] analyzed the CEUS characteristics of RCC in relation to tumor size. Their studies showed that heterogeneous enhancement was mainly seen in tumors> 3 cm (72.9-91%), compared to 28.2-55% in tumors≤3 cm.…”

The independent indicators of contrast-enhanced ultrasound for predicting renal cell carcinoma

“…Compared with the normal renal parenchyma, RCCs often exhibit fast wash out, while AMLs more often show slow wash out [22]. Xue et al [23] Sun et al [24] reported that 26%(5/19) of AMLs were fast wash out, while, 74% lesions were confirmed by two enhanced imaging examinations including CEUS and CT/MRI. In our study, all the lesions were diagnosed via surgical pathology and only 4.5% (1/22) of AMLs were fast wash out.…”

“…This may be related to the size of the tumors included in this study. Moreover, Jiang et al [26] Xue et al [23] and Xu et al [27] analyzed the CEUS characteristics of RCC in relation to tumor size. Their studies showed that heterogeneous enhancement was mainly seen in tumors > 3 cm (72.9-91%), compared to 28.2-55% in tumors ≤ 3 cm.…”