Renal cell carcinoma.

higher in smokers, hypertensive or obese patients, and those who have had occupational exposure to cadmium

develop acquired polycystic disease as a complication of chronic dialysis

Types:

Clear Cell Carcinomas

Papillary Renal Cell Carcinomas

Chromophobe Renal Carcinomas

Clear Cell Carcinomas :

Whereas the majority of them are sporadic, they also occur in familial forms or in association with von Hippel-Lindau (VHL) disease

VHL: hemangioblastomas of the cerebellum and retina. Hundreds of bilateral renal cysts and bilateral, often multiple, clear cell carcinomas develop in 40% to 60% of individuals

the loss of both copies of this tumor suppressor gene gives rise to clear cell carcinoma.

Morphology

yellow to orange to gray-white, with prominent areas of cystic softening or of hemorrhage

small processes project into the surrounding parenchyma and small satellite nodules are found in the surrounding substance

it may fungate through the walls of the collecting system, extending through the calyces and pelvis as far as the ureter

the tumor invades the renal vein and grows as a solid column within this vessel, sometimes extending in serpentine fashion as far as the inferior vena cava and even into the right side of the heart. Occasionally, there is direct invasion into the perinephric fat and adrenal gland

The classic vacuolated (lipid-laden), or clear cells are demarcated only by their cell membranes

At the other extreme are granular cells, resembling the tubular epithelium, which have small, round, regular nuclei enclosed within granular pink cytoplasm

Some tumors exhibit marked degrees of anaplasia, with numerous mitotic figures and markedly enlarged, hyperchromatic, pleomorphic nuclei

The cells may form abortive tubules or may cluster in cords or disorganized masses. The stroma is usually scant but highly vascularized

Papillary Renal Cell Carcinomas :

frequently multifocal and bilateral and appear as early-stage tumors

MET proto-oncogene, located on chromosome 7q31

Papillary renal cell carcinomas exhibit varying degrees of papilla formation with fibrovascular cores. They tend to be bilateral and multiple. They may also show gross evidence of necrosis, hemorrhage, and cystic degeneration, but they are less vibrantly orange-yellow because of their lower lipid content. The cells can have clear or, more commonly, pink cytoplasm.

Chromophobe Renal Carcinomas :

They arise from intercalated cells of collecting ducts

Pale eosinophilic cells with perinuclear halo

multiple losses of entire chromosomes, including chromosomes 1, 2, 6, 10, 13, 17, and 21. Thus, they show extreme hypodiploidy

Renal cell carcinoma. Typical cross-section of yellowish, spherical neoplasm in one pole of the kidney. Note the tumor in the dilated thrombosed renal vein.