Uncommon and recently described renal carcinomas

Area of Science:

• Uropathology
• Renal Pathology
• Oncology

Background:

• The 2004 World Health Organization (WHO) classification of renal carcinoma was based on consensus conferences held over a decade prior.
• Clear cell, papillary, and chromophobe carcinomas constitute the vast majority (85-90%) of renal cancers encountered in clinical practice.
• The remaining 10-15% encompass rare sporadic and hereditary tumors, with many identified as distinct entities shortly before the WHO publication.

Purpose of the Study:

• To review the classification of renal carcinoma, emphasizing the distinction between common and rare types.
• To highlight newly recognized rare renal carcinoma entities and their significance.
• To underscore the importance of recognizing rare renal tumors for accurate surgical pathology diagnosis.

Main Methods:

• Review of major consensus conference findings and the 2004 WHO classification of renal carcinoma.
• Analysis of the spectrum of renal carcinoma subtypes, including common and rare forms.
• Identification of recently described rare renal carcinoma entities.

Main Results:

• Common renal carcinomas (clear cell, papillary, chromophobe) account for 85-90% of cases.
• Rare renal carcinomas include collecting-duct carcinoma, medullary carcinoma associated with sickle cell trait, mucinous tubular and spindle-cell carcinoma, and tubulocystic carcinoma.
• Other rare entities include TFE3/TFEB-associated pediatric renal carcinomas, oncocytoid renal carcinomas in neuroblastoma survivors, renal carcinoma associated with end-stage renal disease, clear cell papillary carcinoma, oncocytic papillary renal cell carcinoma, follicular renal carcinoma, and leiomyomatous renal cell carcinoma.

Conclusions:

• The 2004 WHO classification incorporates common and numerous rare renal carcinoma entities.
• Surgical pathologists must be adept at diagnosing both common and rare renal cancers, including recently identified types.
• Accurate diagnosis of rare renal carcinomas is essential due to their distinct morphological features and behaviors.