Benign Tumors
Benign tumors of the kidney are relatively common, especially in atrophic kidneys of adults and the elderly. They are usually very small, a few millimeters in diameter and are usually as autopsy findings, as they have no clinical manifestations. These include fibroids of the marrow and renal cortex, found in 10 to 35% of autopsies, and cortical adenomas, which are observed in 20% of the autopsies.
Adenomas are benign tumors of renal cell can be tubular or papillary. When they are larger than 3 cm in diameter, are difficult to distinguish from renal cell carcinomas and in this case are considered tumors of uncertain biological behavior.
Benign tumors of the kidney are very characteristic: the reninoma, oncocytoma and angiomyolipoma
Reninoma
Is a tumor of the juxtaglomerular apparatus consisting of renin-producing cells. This substance can be identified by immunohistochemistry and electron microscopy. Usually not a large tumor and clinically manifests with hypertension.
Oncocytoma
Is a tumor composed of oncocytic renal cell (cells rich in mitochondria). This tumor can be large and resemble a renal cell carcinoma.
Angiomyolipoma
This tumor belongs to the group of hamartomas. It consists of mature adipose tissue, blood vessels without elastic fibers and smooth muscle fiber bundles. Its size is variable, can reach 20 cm in diameter. In 80% of cases are associated with cerebral tuberous sclerosis (Bourneville disease). It is observed more frequently in women between 40 and 50 years of age. Clinically manifested by pain, fever, hematuria and hypertension.