50: Renal Cell Carcinoma

Key Points

• Disease summary:

  • Approximately 50,000 new cases of renal cell carcinoma (RCC) are diagnosed each year.

  • RCCs are adenocarcinomas derived from renal tubular epithelium. Renal carinoma is comprised of several different types of cancer, each with a different histologic type, with a different clinical course, responding differently to therapy, and caused by different genes.

• Histologically, there are five subtypes:

  • Conventional (clear cell) (70%-80%)

  • Chromophile (papillary) (10%-15%). Papillary is further classified into type 1 (5%) and type 2 (10% of cases) based on further genetic alterations, histologic, and genetic criteria

  • Chromophobe (3%-5%)

  • Collecting duct (1%)

  • Unclassified (1%)

• RCC can be hereditary as well as sporadic or nonhereditary. While sporadic RCC is often a solitary lesion and most commonly presents in individuals in their 60s, inherited forms tend to be multifocal, bilateral, and have an earlier onset.

• Hereditary basis:

  • Renal cancer is hereditary in up to 4% of cases, and follows an autosomal dominant inheritance pattern with incomplete penetrance. In the absence of a diagnosed syndrome, the risk for family members of patients with RCC may increase fivefold. The highest risk appears to be confined to siblings of renal cell cancer patients, arguing for the potential of low penetrance genes acting in concert to elevate the risk of disease.

• Differential diagnosis:

  • It is important to distinguish the multiorgan system syndromes that include renal cancer as a single feature (ie, von Hippel-Lindau [VHL], Birt-Hogg-Dubé [BHD], and hereditary leiomyomatosis renal cell cancer [HLRCC]) from the familial tumor predispositions (ie, hereditary papillary renal carcinoma [HPRC]), in which renal cancer is the only major finding. Thus, it is imperative to inquire about associated features if there is clinical suspicion for an inherited syndrome in order to establish a clinical diagnosis or indication for genetic (germline) testing (Table 50-1).

Diagnostic Criteria and Clinical Characteristics

Diagnostic Criteria for Hereditary Renal Cancer

Inherited forms ...