Small renal cell carcinoma: pathologic and radiologic correlation.

Abstract

The authors correlated the radiologic and pathologic findings of 36 patients with small renal cell carcinoma (less than or equal to 3 cm in diameter). Tumors were discovered incidentally or by means of mass surveys with ultrasound (US). Computed tomography (CT) and angiography were performed before surgery. Of the 36 tumors, 24 were of solid (alveolar) architecture, five were of papillary architecture, three were of tubular architecture, and four were of multilocular cystic architecture. Cell arrangement was closely correlated with radiologic appearance, especially in regard to tumor vascularity and echogenicity. Histologically homogeneous tumors of solid architecture were hypoechoic at US and hypervascular at angiography and contrast medium-enhanced CT. Tumors of papillary, tubular, and multilocular cystic architecture were hyperechoic at US and hypovascular at angiography. There was no correlation of cell differentiation and cell architecture with echogenicity or tumor vascularity. Tumors with hemorrhage showed marked hyperattenuation at CT. A tumor capsule was observed in 25 patients (69%); this was demonstrated as a rim at US or angiography.

Differentiation of small hyperechoic renal cell carcinoma from angiomyolipoma: computer-aided tissue echo quantification.

“…[3][4][5][6] These findings were fairly specific but not sensitive enough. 6,7 In our experience as well as that of others, AML tend to be more echogenic than RCC. 3,7,[8][9][10] Some investigators tried to differentiate these two tumors using a visual assessment of echogenicity alone without satisfactory results.…”

“…6,7 In our experience as well as that of others, AML tend to be more echogenic than RCC. 3,7,[8][9][10] Some investigators tried to differentiate these two tumors using a visual assessment of echogenicity alone without satisfactory results. 3,6 The purposes of this study were to evaluate the echogenicity of renal masses objectively and quantitatively by using CATEQ technique and to assess the value of this technique in differentiating small hyperechoic RCC from AML.…”

“…In the earlier studies, most RCC were hypoechoic or isoechoic to the renal parenchyma, with hyperechoic tumors being less common. 6,7,17 In those studies, however, because of equipment limitations, the patient population studied tended to be biased toward those with larger and clinically apparent tumors. Later reports showed that small asymptomatic RCC frequently are hyperechoic with respect to the renal parenchyma.…”

“…Later reports showed that small asymptomatic RCC frequently are hyperechoic with respect to the renal parenchyma. 6,7,12,18 Yamashita and coauthors, 7 in their correlative study of ultrasonographic and pathologic findings, stated that the cellular arrangement was the most important factor for the echogenicity of small RCC and that their hyperechogenicity may be due to the multiple interfaces formed by small spaces between tumor cells. Recent reports have stressed that some RCC are as echogenic as AML; an echogenicity equal to that of renal sinus fat seen in a small renal mass is, therefore, no longer considered adequate to exclude the diagnosis of malignancy.…”

“…Recent reports have stressed that some RCC are as echogenic as AML; an echogenicity equal to that of renal sinus fat seen in a small renal mass is, therefore, no longer considered adequate to exclude the diagnosis of malignancy. 6,7 Previous efforts have been made to differentiate RCC and AML on the basis of sonographic characteristics, such as presence of intramural cysts and an anechoic rim in RCC and presence of posterior acoustic shadowing in AML. Yamashita and coauthors, in their study of hyperechoic renal masses of less than 5 cm, noted that RCC exclusively showed an anechoic rim (84%, 32 of 38) and intramural cyst (26%, 10 of 38).…”