Staging of Renal Cell Carcinoma

Survival rates in patients with renal cell carcinoma have been correlated with the extent of tumor at the time of presentation.226-229 The Robson system of staging226 is still used by most urologists, but the TNM system230 is also used, especially in Europe (Table 8-2).

Perirenal Fat

Fig. 8—175. Contrast extravasation during percutaneous nephrostomy outlines bridging perirenal septa.

(a and b) Fortuitous in vivo CT observations at two levels show multiple septa through the perirenal fat and contrast loculation (L) by a bridging dorsal renorenal septum. Note that the medial and lateral insertions of this septum vary somewhat at different levels. The fluid loculation may mimic a subcapsular collection. (Courtesy of Michiel Feldberg, M.D., University of Utrecht, The Netherlands.)

Fig. 8—175. Contrast extravasation during percutaneous nephrostomy outlines bridging perirenal septa.

(a and b) Fortuitous in vivo CT observations at two levels show multiple septa through the perirenal fat and contrast loculation (L) by a bridging dorsal renorenal septum. Note that the medial and lateral insertions of this septum vary somewhat at different levels. The fluid loculation may mimic a subcapsular collection. (Courtesy of Michiel Feldberg, M.D., University of Utrecht, The Netherlands.)

Renal Fascia Lines

Fig. 8-176. Bleeding deep to renorenal septum mimicking a subcapsular hematoma.

(a) Small hematoma confined by the posterior renorenal bridging septum. Dark line (black arrows) between renal parenchyma (K) and hematoma (white arrows) is thought by some to represent swollen renal capsule and by others a CT artifact. The blood extends within another thickened septum to the posterior renal fascia, which bounds a collection of blood within the posterior pararenal space (P). Sp = spleen.

(b) The hematoma extends external to the renal capsule from the posteromedial to the posterolateral aspect of the kidney. Laterally it becomes beak-shaped where it is tethered by another septum bridging to the renal fascia (open arrow). Tension within the hematoma deep to the renorenal septum displaces the kidney anteriorly.

These findings were proved at autopsy.

Fig. 8-176. Bleeding deep to renorenal septum mimicking a subcapsular hematoma.

(a) Small hematoma confined by the posterior renorenal bridging septum. Dark line (black arrows) between renal parenchyma (K) and hematoma (white arrows) is thought by some to represent swollen renal capsule and by others a CT artifact. The blood extends within another thickened septum to the posterior renal fascia, which bounds a collection of blood within the posterior pararenal space (P). Sp = spleen.

(b) The hematoma extends external to the renal capsule from the posteromedial to the posterolateral aspect of the kidney. Laterally it becomes beak-shaped where it is tethered by another septum bridging to the renal fascia (open arrow). Tension within the hematoma deep to the renorenal septum displaces the kidney anteriorly.

These findings were proved at autopsy.

Fig. 8-177. Loculated perirenal blood along bridging septa to the interfascial space.

(a and b) In a patient with acquired renal cystic disease secondary to dialysis, CT demonstrates the pathway of perirenal hemorrhage to the intralaminar posterior renal fascia via a bridging septum (arrow). (Courtesy of Michiel Feldberg, M.D., University of Utrecht, The Netherlands.)

Fig. 8-177. Loculated perirenal blood along bridging septa to the interfascial space.

(a and b) In a patient with acquired renal cystic disease secondary to dialysis, CT demonstrates the pathway of perirenal hemorrhage to the intralaminar posterior renal fascia via a bridging septum (arrow). (Courtesy of Michiel Feldberg, M.D., University of Utrecht, The Netherlands.)

Robson Staging
Table 8-2. Staging renal cell carcinoma: Robson's classification versus TNM

Robs on

Disease extent

TNM

I

Tumor confined to kidney (small, intrarenal)

T1

Tumor confined to kidney (large)

T2

II

Tumor spread to perirenal fat, but within Gerota's fascia

T3a

IIIA

Tumor spread to renal vein or cava

T3b

urn

Tumor spread to local lymph nodes

N1-N3

IIIC

Tumor spread to local vessels and lymph nodes

T3b, N1-N3

IVA

Tumor spread to adjacent organs (excluding ipsillateral adrenal)

T4

IVB

Distant metastasis

Mla-d, N4

Stage I denotes lesions entirely confined within the renal capsule (Fig. 8-178). Stage II indicates extension through the capsule into the perirenal fat but not beyond the renal fascia (Fig. 8-179). Distinction between stages I and II by CT or MRI may be difficult. Thickening of the renal fascia or bridging septa and dilated tortuous perirenal vessels are not reliable signs of tumor extension. However, both stage I and stage II tumors are resectable, and both have good prognoses.

Stage III designates involvement of the renal veins or inferior vena cava or lymph nodes. Venous extension is very uncommon with tumors smaller than 4.5 cm232 (Figs. 8-180 and 8-181). Since enlarged nodes may be secondary to reactive hyperplasia without harboring tu-mor,233 nephrectomy is often done despite the presence of enlarged nodes.

Stage IV denotes either distant metastases or direct invasion of adjacent visceral structures (Figs. 8-182 and 8-183). Local extension can be detected by MRI more accurately than CT, because the most accurate imaging plane can be selected to avoid volume averaging.234

Computed tomography often readily provides helpful information in preoperative staging, with an accuracy of over 90%.235-237 Extracapsular extension is shown by an indistinct tumor margin with strands of soft-tissue density extending into or obliterating the perirenal fat. Color Doppler sonography may be used as a complementary technique for assessing venous extension in patients with an equivocal CT examination.238 Magnetic resonance imaging appears generally similar to CT in

939-941

staging renal cell carcinoma, but appears superior in differentiating lymphadenopathy from small vascular

Fig. 8-178. Stage I renal cell carcinoma.

Gadolinium-enhanced T1-weighted MR image demonstrates the tumor (arrows) confined within the renal capsule. An enlarged paracaval lymph node (arrowhead) proved to be hyperplastic at pathology. (Reproduced from Narumi et al.231)

Fig. 8—179. Stage II renal cell carcinoma.

Unenhanced Tl-weighted MR image demonstrates the tumor (T) extending into the perirenal fat, but the fat plane between the mass and a bowel loop is preserved (arrows). (Reproduced from Narumi et al.231)

Fig. 8-178. Stage I renal cell carcinoma.

Gadolinium-enhanced T1-weighted MR image demonstrates the tumor (arrows) confined within the renal capsule. An enlarged paracaval lymph node (arrowhead) proved to be hyperplastic at pathology. (Reproduced from Narumi et al.231)

Fig. 8—179. Stage II renal cell carcinoma.

Unenhanced Tl-weighted MR image demonstrates the tumor (T) extending into the perirenal fat, but the fat plane between the mass and a bowel loop is preserved (arrows). (Reproduced from Narumi et al.231)

Fatty Mass KidneyImages Renal Cell Carcinoma

Fig. 8—180. Stage IIIa renal cell carcinoma.

Cine-GRE MR image shows tumor thrombus (arrowhead) in the intrahepatic inferior vena cava, arising from a tumor of the right kidney. (Reproduced from Narumi et al.231)

Fig. 8—181. Stage Ilia right renal cell carcinoma with IVC thrombus.

T1-weighted MR image demonstrates that the thrombus shows two different signal intensities: an intermediate signal anteriorly (arrowhead) and a low signal posteriorly (arrows), which proved pathologically to be tumor thrombus and bland thrombus, respectively. (Reproduced from Narumi et al.231)

Fig. 8—180. Stage IIIa renal cell carcinoma.

Cine-GRE MR image shows tumor thrombus (arrowhead) in the intrahepatic inferior vena cava, arising from a tumor of the right kidney. (Reproduced from Narumi et al.231)

Fig. 8—182. Stage IVa renal cell carcinoma.

(a and b) CT shows the large lobulated tumor mass (M) extending posteriorly from the displaced right kidney

(K) and inferiorly where it invades the ascending colon (AC).

(Courtesy of Michiel Feldberg, M.D., University of Utrecht, The Netherlands.)

Fig. 8—183. Stage IVa right renal carcinoma.

Gadolinium-enhanced T1-weighted axial (a) and sagittal (b) MR images show direct extension of the tumor (T) to a loop of bowel (B), a distinct plane between the tumor and liver, and intratumoral necrosis. (Reproduced from Narumi et al.231)

Fig. 8—183. Stage IVa right renal carcinoma.

Gadolinium-enhanced T1-weighted axial (a) and sagittal (b) MR images show direct extension of the tumor (T) to a loop of bowel (B), a distinct plane between the tumor and liver, and intratumoral necrosis. (Reproduced from Narumi et al.231)

structures and in the detection of venous inva-

231 232 242-244

sion. ' ' MRI may be capable in some cases of distinguishing bland thrombus from tumor thrombus (Fig. 8-181), since only the latter will enhance with Gd-DTPA.

Five-year survival decreases with advancing stage, approximating 60% for stage I lesions and decreasing to less than 10% with stage IV tumors.

Stage I and stage II tumors can be approached by a retroperitoneal incision, whereas stage III and stage IV tumors require an abdominal approach. If the vena cava is involved, a thoracoabdominal approach is required.

The prognosis in patients with vena cava extension depends on whether the tumors can be excised com-pletely.245,246 In patients who have renal vein or vena cava extension without extension outside the renal parenchyma itself and without nodal or distant metastases, the survival at 5 years is 50%. Nodal spread is a poor prognostic indicator, and only 5-10% of these patients c 247

Essentials of Human Physiology

Essentials of Human Physiology

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