Overview and Staging of Renal Neoplasms

Renal cell tumors

 Papillary adenoma


 Clear cell renal cell carcinoma

  Multilocular cystic clear cell renal cell neoplasm of low malignant potentiala

 Papillary renal cell carcinoma

 Chromophobe renal cell carcinoma

  Hybrid oncocytic/chromophobe tumora

 Carcinoma of the collecting ducts of Bellini

 Renal medullary carcinoma

 MiT family translocation renal cell carcinomaa

  Xp11 translocation renal cell carcinoma

  t(6;11) renal cell carcinoma

 Carcinoma associated with neuroblastoma

 Mucinous tubular and spindle cell carcinoma

 Tubulocystic renal cell carcinomaa

 Acquired cystic disease-associated renal cell carcinomaa

 Clear cell (tubulo) papillary renal cell carcinomaa

 Hereditary leiomyomatosis renal cell carcinoma syndrome-associated renal cell carcinomaa

 Renal cell carcinoma, unclassified

Metanephric tumors

 Metanephric adenoma

 Metanephric adenofibroma

 Metanephric stromal tumor

Nephroblastic tumors

 Nephrogenic rests


  Cystic partially differentiated nephroblastoma

Mesenchymal tumors

 Occurring mainly in children

  Clear cell sarcoma

  Rhabdoid tumor

  Congenital mesoblastic nephroma

  Ossifying renal tumor of infants

 Occurring mainly in adults

  Leiomyosarcoma (including renal vein)



  Malignant fibrous histiocytoma



  Synovial sarcomaa


   Epithelioid angiomyolipomaa



  Juxtaglomerular cell tumor

  Renomedullary interstitial cell tumor


  Solitary fibrous tumor

Mixed mesenchymal and epithelial tumors

 Cystic nephroma/mixed epithelial stromal tumor

Neuroendocrine tumors

 Carcinoid (low-grade neuroendocrine tumor)

 Neuroendocrine carcinoma (high-grade neuroendocrine tumor)

 Primitive neuroectodermal tumor



Hematopoietic and lymphoid tumors




Germ cell tumors



Metastatic tumors

Other tumors

aNew additions or changes

Several new subtypes of RCC are recognized in the ISUP Vancouver classification such as tubulocystic RCC, acquired cystic disease-associated RCC, clear cell (tubulo) papillary RCC, MiT family translocation RCC (including t(6;11) RCC), and hereditary leiomyomatosis RCC syndrome-associated RCC. Some newly described RCCs are also considered as provisional entities such as thyroid-like follicular RCC, succinic dehydrogenase B deficiency-associated RCC, and ALK-translocation RCC. Additional data are needed to help shed light on the biology of these rare unique tumors. Some innovations were also made on traditional tumor entities, such as renaming multicystic clear cell RCC as a neoplasm of low malignant potential, subtyping papillary RCC into type 1 or 2, accepting the hybrid oncocytic/chromophobe tumor as a discrete subtype of chromophobe RCC, and merging cystic nephroma with mixed epithelial stromal tumor into one tumor spectrum. Despite the inclusion of these novel entities, clear cell RCC, papillary RCC, and chromophobe RCC still comprise >90 % of the RCCs. The proportion of MiT family translocation RCC however is higher in pediatric and young adult patients.

Staging of Renal Cancers


The tumor node metastasis (TNM) is the most widely accepted staging system for renal cancer [2]. This approach measures the extent of cancer spread at the primary organ site, regional lymph nodes, and distant sites (Table 4.2). The TNM system underwent considerable revisions over the past three decades with its latest edition (seventh) published in 2010, and a new version is being expected within the next 2 years as of 2015. Purely based on the tumor’s anatomic extent, the different TNM stage categories are lumped into four main prognostic groups (Table 4.3). The clinical (c) stage is routinely used as a guide in determining the type of primary management , such as nephron sparing surgery (NSS) or ablative therapies for low stage renal tumors or systemic therapy for advanced stage tumors. The pathologic (p) stage mainly provides prognosis of outcome after surgical resection of renal cancer and is important on the decision for adjuvant therapy. TNM stage is often incorporated in the inclusion criteria and in stratifying patients for clinical therapeutic trials. The accuracy of TNM stage in renal cancer can be further enhanced by its integration in the different prognostic and predictive models such as the MSKCC prognostic nomogram; the Mayo Clinic stage, size, grade, and necrosis (SSIGN) score; and the UCLA integrated staging system (UISS) [37].

Table 4.2
Definitions of the 2010 AJCC TNM staging for renal cancers

Primary tumor (T)


Primary tumor cannot be assessed


No evidence of primary tumor


Tumor 7 cm or less in greatest dimension, limited to the kidney


Tumor 4 cm or less in greatest dimension, limited to the kidney


Tumor more than 4 cm but not more than 7 cm in greatest dimension, limited to the kidney


Tumor more than 7 cm in greatest dimension, limited to the kidney


Tumor more than 7 cm but less than or equal to 10 cm in greatest dimension, limited to the kidney


Tumor more than 10 cm, limited to the kidney


Tumor extends into major veins or perinephric tissues but not into the ipsilateral adrenal gland and not beyond Gerota’s fascia


Tumor grossly extends into the renal vein or its segmental (muscle-containing) branches, or tumor invades perirenal and/or renal sinus fat but not beyond Gerota’s fascia


Tumor grossly extends into the vena cava below the diaphragm


Tumor grossly extends into the vena cava above the diaphragm or invades the wall of the vena cava


Tumor invades beyond Gerota’s fascia (including contiguous extension into the ipsilateral adrenal gland)

Regional lymph nodes (N)


Regional lymph nodes cannot be assessed


No regional lymph node metastasis


Metastasis in regional lymph node (s)

Distant metastasis (M)


No distant metastasis


Distant metastasis

Table 4.3
2010 AJCC TNM anatomic stage or prognostic groupings

Stage I




Stage II




Stage III

T1 or T2




N0 or N1


Stage IV


Any N


Any T

Any N


Historical Background

In 1958, Flocks and Kasdesky [8] introduced one of the first formal stagings for renal cancer based on the tumor’s anatomic extent and patterns of spread. A year later, Petkovic [9] proposed a similar classification that subdivided intrarenal tumors into stages I and II (Flocks and Kasdesky’s stage I). In the 1960s, Robson modified these systems, incorporated venous involvement, and subdivided localized extrarenal spread [10, 11]. However, Robson’s system was hampered by inaccuracies in some of the stage definitions due to the lumping of prognostically different patterns of anatomic spread [11].

First developed in the 1940s by Pierre Denoix in France, the TNM system was adopted by the Union Internationale Contre le Cancer (UICC) , while the American Joint Commission on Cancer (AJCC) used a slightly different classification. In 1987, the UICC and AJCC were unified, and the first major revision of the TNM staging was published that incorporated tumor size cutoffs derived from cross-sectional imaging studies. Since then, the TNM system underwent several major revisions published in 1993 (supplement), 1997, 2002, and the latest in 2010, building on experiences and evidences accumulated from each prior version in order to enhance its prognostic accuracies (Table 4.4). Revisions in the 2010 TNM system include T2 tumors divided into T2a (>7 cm but ≤10 cm) and T2b (>10 cm); ipsilateral adrenal gland contiguous invasion classified as T4 and, if not contiguous as M1, renal vein involvement reclassified as T3a; and nodal involvement simplified into N0 and N1 [2].

Table 4.4
Evolution of renal cancer staging system


Robson (1969)a

UICC/AJCC TNM, fourth edition (1987)

UICC/AJCC TNM, fifth edition (1997)

UICC/AJCC TNM, sixth edition (2002)

UICC/AJCC TNM, seventh edition (2010)


(I) Organ confined, any size

Organ confined, ≤2.5 cm

Organ confined, ≤7 cm


Organ confined, ≤4 cm

Organ confined, ≤4 cm


Organ confined, >4–7 cm

Organ confined, >4–7 cm


(II) Into perinephric tissue

Organ confined, >2.5 cm

Organ confined, >7 cm

Organ confined, >7 cm


Organ confined, >7–10 cm


Organ confined, >10 cm


(IIIa) Renal vein

Perinephric tissue or contiguous adrenal gland extension

Perinephric tissue or contiguous adrenal gland extension

Perinephric or sinus tissue or contiguous adrenal gland extension

Perinephric or sinus tissue or renal vein or its segmental branches


(IIIb) Node involvement

Renal vein

Renal vein or vena cava below diaphragm

Renal vein or vena cava below diaphragm

Vena cava below diaphragm


(IIIc) Both renal vein and node involvement

Vena cava below diaphragm

Vena cava above diaphragm

Vena cava above diaphragm

Vena cava above diaphragm or wall of vena cava at any level


Beyond Gerota’s fascia

Beyond Gerota’s fascia

Beyond Gerota’s fascia or contiguous adrenal gland extension


(IVa) Invasion of adjacent structures

Beyond Gerota’s fascia


(IVb) Distant metastasis

Vena cava above diaphragm

aStaged as I, II, IIIa, IIIb, IIIc, IVa, IVb

Components of the TNM Staging System for Renal Cancer

Organ-Confined Tumors

Tumors 7 cm or Smaller (T1)

Since the 2002 TNM version, T1 tumors are subdivided into T1a and T1b using 4 cm size cutoff (Figs. 4.1 and 4.2). This was mainly based on the study by Hafez et al. [12] wherein they reviewed 485 patients with localized renal cancer treated with NSS and showed a more favorable cancer-free survival in tumors ≤4 cm compared to larger tumors. Since then, the prognostic impact of this subdivision has been validated in subsequent studies [1317]. Despite of several studies suggesting a different optimal size cutoff for T1a and T1b and T1 versus T2, the 4 and 7 cm cutoffs are retained in the current 2010 TNM system [1822]. By incidence, most renal cancers are diagnosed as T1 tumors (~55 to 70 %) and with greater T1a (35–45 %) than T1b cases (19–27 %) (Table 4.5) [2325]. A practical usefulness of this T1 grouping is that most of the current guidelines recommend NSS for T1 renal cancer when technically feasible, and this recommendation is generally accepted for T1a tumors.


Fig. 4.1
Kidney with two synchronous organ-confined tumors . The smaller tumor (top) is T1a and the larger tumor (bottom) is T1b. Multiple tumors are staged according to the highest T stage, in this case as T1b


Fig. 4.2
T1a clear cell RCC that is very close to the hilum. In this case, adequate sampling of the tumor-sinus interface is important to ascertain the absence of invasion (T3a)

Table 4.5
Distribution of renal cancer patients by pathologic T stage


Novara et al. (2010) [23]

Lee et al. (2011) [24]

Pichler et al. (2013) [25]





T1a (%)




T1b (%)


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Nov 27, 2016 | Posted by in NEPHROLOGY | Comments Off on Overview and Staging of Renal Neoplasms

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