WHO classification of tumors of the kidney
The World Health Organization (WHO) classification of tumors of the kidney is the most commonly used pathologic classification system for such disorders. The current revision, part of the 4 edition of the WHO series, was published in 2016 as part of the WHO Classification of Tumors of the Urinary System and Male Genital Organs . It is heavily based upon the International Society of Urological Pathology (ISUP) Vancouver classification of renal neoplasia of 2013 and supercedes the 2004 WHO classification. The 2016 version is reflected in the article below.
Classification
Renal cell tumors
- clear cell renal cell carcinoma
- multilocular cystic renal neoplasm of low malignant potential
- papillary renal cell carcinoma
- hereditary leiomyomatosis and renal cell carcinoma-associated renal cell carcinoma
- chromophobe renal cell carcinoma
- collecting duct carcinoma
- renal medullary carcinoma
- MiT family translocation renal cell carcinoma
- succinate dehydrogenase-deficient renal carcinoma
- mucinous tubular and spindle cell carcinoma
- tubulocystic renal cell carcinoma
- acquired cystic disease-associated renal cell carcinoma
- clear cell papillary renal cell carcinoma
- renal cell carcinoma, unclassified
- papillary adenoma
- oncocytoma
Metanephric tumors
- metanephric adenoma
- metanephric adenofibroma
- metanephric stromal tumor
Nephroblastic and cystic tumors occurring mainly in children
- nephrogenic rests
- nephroblastoma
- cystic partially differentiated nephroblastoma
- pediatric cystic nephroma
Mesenchymal tumors occurring mainly in children
Mesenchymal tumors occurring mainly in adults
- leiomyosarcoma
- angiosarcoma
- rhabdomyosarcoma
- osteosarcoma
- synovial sarcoma
- Ewing sarcoma
- angiomyolipoma
- epithelioid angiomyolipoma
- leiomyoma
- hemangioma
- lymphangioma
- hemangioblastoma
- juxtaglomerular cell tumor
- renomedullary interstitial cell tumor
- schwannoma
- solitary fibrous tumor
Mixed epithelial and stromal tumor family
Neuroendocrine tumors
- well-differentiated neuroendocrine tumor
- large cell neuroendocrine carcinoma
- small cell neuroendocrine carcinoma
- pheochromocytoma
Miscellaneous tumors
- renal hematopoietic neoplasms
- germ cell tumors of the kidney
Metastatic tumors
Changes from prior versions
Several but not all familial forms of renal cell carcinoma have been subsumed into the corresponding histology, which can also arise sporadically (e.g. clear cell renal cell carcinoma in von Hippel-Lindau disease, chromophobe renal cell carcinoma in Birt-Hogg-Dubé (BHD) syndrome).
The entity previously known as multilocular cystic renal cell carcinoma or multilocular clear cell renal cell carcinoma is now described as multilocular cystic renal neoplasm of low malignant potential in recognition of the low incidence of recurrence and metastasis.
The size cutoff for papillary adenoma was increased from ≤0.5 cm to ≤1.5 cm.
Cystic nephroma has been divided into the adult and pediatric forms. The adult form is included along a spectrum of mixed epithelial and stromal tumors.
Renal carcinoids have been redesignated well-differentiated neuroendocrine tumors of the kidney and placed in a group with small cell neuroendocrine carcinomas, large cell neuroendocrine carcinomas, and paragangliomas (extra-adrenal pheochromocytoma).
Several entities are newly established:
- hereditary leiomyomatosis and renal cell carcinoma-associated renal cell carcinoma
- succinate dehydrogenase-deficient renal carcinoma
- tubulocystic renal cell carcinoma
- acquired cystic disease-associated renal cell carcinoma
- clear cell papillary renal cell carcinoma
- pediatric cystic nephroma