Renal cell carcinoma pathophysiology

Overview
Renal cell carcinoma is the most common form of kidney cancer arising from the renal tubule. It is the most common type of kidney cancer in adults. Initial treatment is surgery. It is notoriously resistant to radiation therapy and chemotherapy, although some cases respond to immunotherapy. The advent of targeted cancer therapies such as sunitinib has vastly improved the outlook for treatment of RCC.

Classification and pathophysiology
Recent genetic studies have altered the approaches used in classifying renal cell carcinoma. The following system can be used to classify these tumors:


 * Clear cell carcinoma (VHL and others on chromosome 3)
 * Papillary carcinoma (MET, PRCC)
 * Chromophobe renal carcinoma
 * Collecting duct carcinoma

Other associated genes include TRC8, OGG1, HNF1A, HNF1B, TFE3, RCCP3, and RCC17.

Overview
Other images of kidney cancer can be seen through simple instruments such as microscopes.

Pathology
Gross examination shows a hypervascular lesion in the renal cortex, which is frequently multilobulated, yellow (because of the lipid accumulation) and calcified.

Light microscopy shows tumor cells forming cords, papillae, tubules or nests, and are atypical, polygonal and large. Because these cells accumulate glycogen and lipids, their cytoplasm appear "clear", lipid-laden, the nuclei remain in the middle of the cells, and the cellular membrane is evident. Some cells may be smaller, with eosinophilic cytoplasm, resembling normal tubular cells. The stroma is reduced, but well vascularized. The tumor grows in large front, compressing the surrounding parenchyma, producing a pseudocapsule.

Secretion of vasoactive substances (e.g. renin) may cause arterial hypertension, and release of erythropoietin may cause polycythemia (increased production of red blood cells).