Overview
Classification
The pathology report plays a vital role in the management of renal cell carcinoma (RCC).1 It provides the urologist and oncologist with an accurate diagnosis and prognostic information, which facilitates appropriate decisions on further patient care, such as the requirement for adjuvant treatment (e.g. with targeted agents) and development of a suitable follow-up schedule. Retrieval of the maximum amount of information requires correct handling of the tumour specimen at all time points and relies on collaboration between pathologists and clinicians, urologists and oncologists.
For a long time, only a few cellular subtypes of RCC were recognized. However, the advent of immunohistochemical methods, together with genetic studies, has made it possible to recognize multiple cell subtypes with both genetic and biological differences. This is reflected in the WHO 2004 classification (Table 3.1),2,3 based on histological and genetic features, which recognizes a growing number of relevant clinico pathological subtypes with differing histogenesis and prognosis.
| Malignant tumours | Benign tumours |
| Clear-cell RCC | Paplllary adenoma |
| Multilocular cystic clear-cell RCC | Oncocytoma |
| Papillary RCC | |
| Chromophobe RCC | |
| Carcinoma of the collecting ducts of Bellini | |
| Renal medullary carcinoma | |
| Xp11 translocation carcinomas | |
| Mucinous tubular and spindle cell carcinoma | |
| Carcinoma associated with neuroblastoma | |
| RCC, unclassified |
Table 3.1 WHO histological classification of renal cell tumours.2,3 Adapted from Eble et al. 2004 with kind permission from Springer.
RCCs may be sporadic or inherited.
| Primary tumour (T) | |
| TX | Primary tumour cannot be assessed |
| T0 | No evidence of primary tumour |
| T1 | Tumour 7 cm or less in greatest dimension, limited to the kidney |
| T1a | Tumour 4 cm or less in greatest dimension, limited to the kidney |
| T1b | Tumour more than 4 cm but not more than 7 cm in greatest dimension, limited to the kidney |
| T2 | Tumour more than 7 cm in greatest dimension, limited to the kidney |
| T2a | Tumour more than 7 cm but less than or equal to 10 cm in greatest dimension, limited to the kidney |
| T2b | Tumour more than 10 cm, limited to the kidney |
| T3 | Tumour extends into major veins or perinephric tissues but not into the ipsilateral adrenal gland and not beyond Gerota’s fascia |
| T3a | Tumour grossly extends into the renal vein or its segmental (muscle-containing) branches, or tumour invades perirenal and/or renal sinus fat but not beyond Gerota’s fascia |
| T3b | Tumour grossly extends into the vena cava below the diaphragm |
| T3c | Tumour grossly extends into vena cava above the diaphragm or invades the wall of the vena cava |
| T4 | Tumour invades beyond Gerota’s fascia (including contiguous extension into the ipsilateral adrenal gland) |
| Regional lymph nodes (N) | |
| NX | Regional lymph nodes cannot be assessed |
| N0 | No regional lymph node metastasis |
| N1 | Metastasis in regional lymph node(s) |
| Distant metastasis (M) | |
| M0 | No distant metastasis |
| M1 | Distant metastasis |
Table 3.5 The 2010 TNM classification
This information has been provided with the kind permission of Vincent Molinié,Mathilde Sibony, Jérôme Couturier and Annick Vieillefond
References:
1. Kirkali Z, Algaba F, Scarpelli M et al. What does the urologist expect from the pathologist (and what can the pathologists give) in reporting on adult kidney tumour specimens? Eur Urol 2007;51:1194–1201.
2. Lopez-Beltran A, Scarpelli M, Montironi R, Kirkali Z. 2004 WHO classification of the renal tumors of the adults. Eur Urol 2006;49:798–805.
3. Eble JN, Sauter G, Epstein JI, Sesterhenn IA. World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of the Urinary System and Male Genital Organs. Lyon, France: IARC Press; 2004.