Imaging and Screening of Kidney Cancer

Abstract

Renal cell carcinoma (RCC) exhibits a diverse and heterogeneous disease spectrum, but insight into its molecular biology has provided an improved understanding of potential risk factors, oncologic behavior, and imaging features. Computed tomography (CT) and MR imaging may allow the identification and preoperative subtyping of RCC and assessment of a response to various therapies. Active surveillance is a viable management option in some patients and has provided further insight into the natural history of RCC, including the favorable prognosis of cystic neoplasms. This article reviews CT and MR imaging in RCC and the role of screening in selected high-risk populations.

Keywords: Active surveillance; Bosniak classification; Computed tomography imaging; Kidney cancer; MR imaging; Screening.

Fig. 1. Incidence in Kidney Cancer in the U.S

A sustained increased in the incidence of kidney cancer has not translated into a decreased mortality. Data from the “Surveillance, epidemiology, and End Results” [SEER] Database from the National Cancer Institute [NCI]) (http://seer.cancer.gov/).

Fig. 2. Solid renal mass identified on a single phase dual-energy CT scan obtained after the patient presented to the emergency room with abdominal pain

(A) Post-contrast coronal CT image of the upper abdomen, obtained during the portal venous phase, shows a partially exophytic mass (white arrow) arising from the upper-mid right kidney, which appears hypoattenuating relative to the renal parenchyma, but demonstrated an attenuation near 80 Hounsfield units (HU). (B) Reconstructed iodine-only image clearly demonstrates iodine accumulation within the lesion (1.8 mg/mL), consistent with a solid renal neoplasm (white arrow). On the (c) reconstructed water-only image, the mass (white arrow) appears iso- to hyperattenuating (near 40 HU). The attenuation difference between the reconstructed water-only and the post-contrast images also confirms the lesion corresponds to a solid, enhancing mass. (D) Post-contrast subtraction MR image from a subsequently performed MR confirms enhancement within the mass. The patient is scheduled to undergo a percutaneous biopsy and radiofrequency ablation in the near future.

Fig. 2. Solid renal mass identified on a single phase dual-energy CT scan obtained after the patient presented to the emergency room with abdominal pain

(A) Post-contrast coronal CT image of the upper abdomen, obtained during the portal venous phase, shows a partially exophytic mass (white arrow) arising from the upper-mid right kidney, which appears hypoattenuating relative to the renal parenchyma, but demonstrated an attenuation near 80 Hounsfield units (HU). (B) Reconstructed iodine-only image clearly demonstrates iodine accumulation within the lesion (1.8 mg/mL), consistent with a solid renal neoplasm (white arrow). On the (c) reconstructed water-only image, the mass (white arrow) appears iso- to hyperattenuating (near 40 HU). The attenuation difference between the reconstructed water-only and the post-contrast images also confirms the lesion corresponds to a solid, enhancing mass. (D) Post-contrast subtraction MR image from a subsequently performed MR confirms enhancement within the mass. The patient is scheduled to undergo a percutaneous biopsy and radiofrequency ablation in the near future.

Fig. 2. Solid renal mass identified on a single phase dual-energy CT scan obtained after the patient presented to the emergency room with abdominal pain

(A) Post-contrast coronal CT image of the upper abdomen, obtained during the portal venous phase, shows a partially exophytic mass (white arrow) arising from the upper-mid right kidney, which appears hypoattenuating relative to the renal parenchyma, but demonstrated an attenuation near 80 Hounsfield units (HU). (B) Reconstructed iodine-only image clearly demonstrates iodine accumulation within the lesion (1.8 mg/mL), consistent with a solid renal neoplasm (white arrow). On the (c) reconstructed water-only image, the mass (white arrow) appears iso- to hyperattenuating (near 40 HU). The attenuation difference between the reconstructed water-only and the post-contrast images also confirms the lesion corresponds to a solid, enhancing mass. (D) Post-contrast subtraction MR image from a subsequently performed MR confirms enhancement within the mass. The patient is scheduled to undergo a percutaneous biopsy and radiofrequency ablation in the near future.

Fig. 2. Solid renal mass identified on a single phase dual-energy CT scan obtained after the patient presented to the emergency room with abdominal pain

(A) Post-contrast coronal CT image of the upper abdomen, obtained during the portal venous phase, shows a partially exophytic mass (white arrow) arising from the upper-mid right kidney, which appears hypoattenuating relative to the renal parenchyma, but demonstrated an attenuation near 80 Hounsfield units (HU). (B) Reconstructed iodine-only image clearly demonstrates iodine accumulation within the lesion (1.8 mg/mL), consistent with a solid renal neoplasm (white arrow). On the (c) reconstructed water-only image, the mass (white arrow) appears iso- to hyperattenuating (near 40 HU). The attenuation difference between the reconstructed water-only and the post-contrast images also confirms the lesion corresponds to a solid, enhancing mass. (D) Post-contrast subtraction MR image from a subsequently performed MR confirms enhancement within the mass. The patient is scheduled to undergo a percutaneous biopsy and radiofrequency ablation in the near future.

Fig. 3. Mutilocular cystic neoplasm of low malignant potential

Coronal (a) T2-weighted and (b) post-contrast images of the right kidney demonstrate a complex cystic mass in the medial lower pole containing several thickened, enhancing septations without a discrete nodular component. The mass was resected and confirmed to represent a multilocular cystic neoplasm of low malignant potential (ISUP grade 1).

Fig. 3. Mutilocular cystic neoplasm of low malignant potential

Coronal (a) T2-weighted and (b) post-contrast images of the right kidney demonstrate a complex cystic mass in the medial lower pole containing several thickened, enhancing septations without a discrete nodular component. The mass was resected and confirmed to represent a multilocular cystic neoplasm of low malignant potential (ISUP grade 1).

Fig. 4. Bosniak IV cyst in the left kidney

Coronal (a) T2-weighted (b) post-contrast images demonstrate a complex cystic lesion in the lower pole of the left kidney containing multiple thickened septations, in addition to several more discrete-appearing nodule within one of the septa (arrowhead), consistent with a Bosniak IV cyst. The lesion was resected and found to represent a clear cell renal cell carcinoma (ISUP grade 2). Note a few additional simple, Bosniak I cysts in the left kidney.

Fig. 4. Bosniak IV cyst in the left kidney

Coronal (a) T2-weighted (b) post-contrast images demonstrate a complex cystic lesion in the lower pole of the left kidney containing multiple thickened septations, in addition to several more discrete-appearing nodule within one of the septa (arrowhead), consistent with a Bosniak IV cyst. The lesion was resected and found to represent a clear cell renal cell carcinoma (ISUP grade 2). Note a few additional simple, Bosniak I cysts in the left kidney.

Fig. 5. Papillary renal cell carcinoma

(A) Coronal T2-weighted image shows a complex cystic-appearing mass in the upper pole of the right kidney (white arrow) with thickened walls, septa, and an possible mural nodule along its inferior wall (white arrowhead). Coronal (b) pre-contrast fat saturated gradient echo image shows areas of high signal intensity in the lesion related to the kidney (asterisk) suggestive of hemorrhagic contents. (C) post-contrast subtraction image demonstrates an irregular-appearing and enhancing mural nodule along its inferior wall (white arrowhead). The mass was subsequently resected and confirmed to represent a papillary renal cell carcinoma (with features of type 1 and type 2; ISUP grade 3).

Fig. 5. Papillary renal cell carcinoma

(A) Coronal T2-weighted image shows a complex cystic-appearing mass in the upper pole of the right kidney (white arrow) with thickened walls, septa, and an possible mural nodule along its inferior wall (white arrowhead). Coronal (b) pre-contrast fat saturated gradient echo image shows areas of high signal intensity in the lesion related to the kidney (asterisk) suggestive of hemorrhagic contents. (C) post-contrast subtraction image demonstrates an irregular-appearing and enhancing mural nodule along its inferior wall (white arrowhead). The mass was subsequently resected and confirmed to represent a papillary renal cell carcinoma (with features of type 1 and type 2; ISUP grade 3).

Fig. 5. Papillary renal cell carcinoma

(A) Coronal T2-weighted image shows a complex cystic-appearing mass in the upper pole of the right kidney (white arrow) with thickened walls, septa, and an possible mural nodule along its inferior wall (white arrowhead). Coronal (b) pre-contrast fat saturated gradient echo image shows areas of high signal intensity in the lesion related to the kidney (asterisk) suggestive of hemorrhagic contents. (C) post-contrast subtraction image demonstrates an irregular-appearing and enhancing mural nodule along its inferior wall (white arrowhead). The mass was subsequently resected and confirmed to represent a papillary renal cell carcinoma (with features of type 1 and type 2; ISUP grade 3).

Fig. 6. Expected imaging appearance after radiofrequency ablation (i.e. the “halo” sign) of a papillary renal cell carcinoma

(A) Coronal post-contrast CT image acquired during the nephrographic phase shows a hypoenhancing mass (white arrow) compared to the pre-contrast image (not shown) arising from the lower pole of the kidney, proven to be a papillary renal cell carcinoma (type 1; ISUP grade 3) on biopsy performed immediately before radiofrequency ablation (RFA). On the MRI performed 3 months after ablation, (b) coronal T2-, (c) coronal pre-contrast T1-, and (d) and coronal post-contrast subtraction images show the treated tumor as a mass-like, non-enhancing region of coagulative necrosis (hypointense on T2- and hyperintense on T1-weighted images) surrounded by fat (white asterisk). Note the overlying thin, subtle rim of enhancement (white arrowhead) representing fibrous tissue and defining the region of the ablation zone.

Fig. 6. Expected imaging appearance after radiofrequency ablation (i.e. the “halo” sign) of a papillary renal cell carcinoma

(A) Coronal post-contrast CT image acquired during the nephrographic phase shows a hypoenhancing mass (white arrow) compared to the pre-contrast image (not shown) arising from the lower pole of the kidney, proven to be a papillary renal cell carcinoma (type 1; ISUP grade 3) on biopsy performed immediately before radiofrequency ablation (RFA). On the MRI performed 3 months after ablation, (b) coronal T2-, (c) coronal pre-contrast T1-, and (d) and coronal post-contrast subtraction images show the treated tumor as a mass-like, non-enhancing region of coagulative necrosis (hypointense on T2- and hyperintense on T1-weighted images) surrounded by fat (white asterisk). Note the overlying thin, subtle rim of enhancement (white arrowhead) representing fibrous tissue and defining the region of the ablation zone.

Fig. 6. Expected imaging appearance after radiofrequency ablation (i.e. the “halo” sign) of a papillary renal cell carcinoma

(A) Coronal post-contrast CT image acquired during the nephrographic phase shows a hypoenhancing mass (white arrow) compared to the pre-contrast image (not shown) arising from the lower pole of the kidney, proven to be a papillary renal cell carcinoma (type 1; ISUP grade 3) on biopsy performed immediately before radiofrequency ablation (RFA). On the MRI performed 3 months after ablation, (b) coronal T2-, (c) coronal pre-contrast T1-, and (d) and coronal post-contrast subtraction images show the treated tumor as a mass-like, non-enhancing region of coagulative necrosis (hypointense on T2- and hyperintense on T1-weighted images) surrounded by fat (white asterisk). Note the overlying thin, subtle rim of enhancement (white arrowhead) representing fibrous tissue and defining the region of the ablation zone.

Fig. 6. Expected imaging appearance after radiofrequency ablation (i.e. the “halo” sign) of a papillary renal cell carcinoma

(A) Coronal post-contrast CT image acquired during the nephrographic phase shows a hypoenhancing mass (white arrow) compared to the pre-contrast image (not shown) arising from the lower pole of the kidney, proven to be a papillary renal cell carcinoma (type 1; ISUP grade 3) on biopsy performed immediately before radiofrequency ablation (RFA). On the MRI performed 3 months after ablation, (b) coronal T2-, (c) coronal pre-contrast T1-, and (d) and coronal post-contrast subtraction images show the treated tumor as a mass-like, non-enhancing region of coagulative necrosis (hypointense on T2- and hyperintense on T1-weighted images) surrounded by fat (white asterisk). Note the overlying thin, subtle rim of enhancement (white arrowhead) representing fibrous tissue and defining the region of the ablation zone.

Fig. 7. Hereditary papillary renal cell carcinoma follow-up imaging

(A) Axial post-contrast CT image demonstrates multiple hypoattenuating lesions which demonstrated subtle hypoenhancement when compared to the pre-contrast image (not shown). A total of 7 lesions were resected, two of which are shown on the image (dashed arrows), and found to represent papillary renal cell carcinomas (type 1; ISUP grade 2). Two additional subcentimeter lesions (solid arrow and arrowhead) were described as too small to further characterize on this CT exam. Axial (b) T2-weighted and (c) post-contrast subtraction images obtained 6 months after the CT and surgical resection shows interval enlargement of the more central lesion (solid arrow), which also shows unequivocal enhancement on the subtraction post-contrast image. Additionally, the more posterior cystic-appearing lesion seen on prior CT (arrowhead) has also enlarged and now demonstrates multiple thickened septa.

Fig. 7. Hereditary papillary renal cell carcinoma follow-up imaging

(A) Axial post-contrast CT image demonstrates multiple hypoattenuating lesions which demonstrated subtle hypoenhancement when compared to the pre-contrast image (not shown). A total of 7 lesions were resected, two of which are shown on the image (dashed arrows), and found to represent papillary renal cell carcinomas (type 1; ISUP grade 2). Two additional subcentimeter lesions (solid arrow and arrowhead) were described as too small to further characterize on this CT exam. Axial (b) T2-weighted and (c) post-contrast subtraction images obtained 6 months after the CT and surgical resection shows interval enlargement of the more central lesion (solid arrow), which also shows unequivocal enhancement on the subtraction post-contrast image. Additionally, the more posterior cystic-appearing lesion seen on prior CT (arrowhead) has also enlarged and now demonstrates multiple thickened septa.

Fig. 7. Hereditary papillary renal cell carcinoma follow-up imaging

(A) Axial post-contrast CT image demonstrates multiple hypoattenuating lesions which demonstrated subtle hypoenhancement when compared to the pre-contrast image (not shown). A total of 7 lesions were resected, two of which are shown on the image (dashed arrows), and found to represent papillary renal cell carcinomas (type 1; ISUP grade 2). Two additional subcentimeter lesions (solid arrow and arrowhead) were described as too small to further characterize on this CT exam. Axial (b) T2-weighted and (c) post-contrast subtraction images obtained 6 months after the CT and surgical resection shows interval enlargement of the more central lesion (solid arrow), which also shows unequivocal enhancement on the subtraction post-contrast image. Additionally, the more posterior cystic-appearing lesion seen on prior CT (arrowhead) has also enlarged and now demonstrates multiple thickened septa.