A renal

oncocytoma An oncocytoma is a tumor made up of oncocytes, epithelial cells characterized by an excessive amount of mitochondria, resulting in an abundant acidophilic, granular cytoplasm. The cells and the tumor that they compose are often benign but sometim ...

is a

tumour A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

of the

kidney The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...

made up of

oncocyte An oncocyte is an epithelial cell characterized by an excessive number of mitochondria, resulting in an abundant acidophilic, granular cytoplasm. Oncocytes can be benign or malignant. Other names Also known as: *'' Hürthle cell'' ( thyroid gla ...

epithelial cells Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellula ...

with an excess amount of

mitochondria A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosi ...

Signs and symptoms

Renal oncocytomas are often asymptomatic and are frequently discovered by chance on a CT or

ultrasound Ultrasound is sound waves with frequency, frequencies higher than the upper audible limit of human hearing range, hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hea ...

of the abdomen. Possible signs and symptoms of a renal oncocytoma include

blood in the urine Hematuria or haematuria is defined as the presence of blood or red blood cells in the urine. “Gross hematuria” occurs when urine appears red, brown, or tea-colored due to the presence of blood. Hematuria may also be subtle and only detectable w ...

, flank pain, and an

abdominal The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...

mass.

Pathophysiology

Renal oncocytoma is thought to arise from the

intercalated cell The collecting duct system of the kidney consists of a series of tubules and ducts that physically connect nephrons to a minor calyx or directly to the renal pelvis. The collecting duct system is the last part of nephron and participates in elect ...

s of

collecting duct The collecting duct system of the kidney consists of a series of tubules and ducts that physically connect nephrons to a minor calyx or directly to the renal pelvis. The collecting duct system is the last part of nephron and participates in elect ...

s of the kidney. It represent 5% to 15% of surgically resected

renal The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...

neoplasm A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

s. Ultrastructurally, the eosinophilic cells have numerous

Histologic appearance

An oncocytoma is an

epithelial Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellula ...

tumor composed of oncocytes, large

eosinophil Eosinophils, sometimes called eosinophiles or, less commonly, acidophils, are a variety of white blood cells (WBCs) and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. A ...

ic cells having small, round, benign-appearing nuclei with large

nucleoli The nucleolus (, plural: nucleoli ) is the largest structure in the nucleus of eukaryotic cells. It is best known as the site of ribosome biogenesis, which is the synthesis of ribosomes. The nucleolus also participates in the formation of sig ...

and excessive amounts of

Diagnosis

In gross appearance, the tumors are tan or mahogany brown, well circumscribed and contain a central scar. They may achieve a large size (up to 12 cm in diameter). The main

differential diagnosis In healthcare, a differential diagnosis (abbreviated DDx) is a method of analysis of a patient's history and physical examination to arrive at the correct diagnosis. It involves distinguishing a particular disease or condition from others that p ...

of renal oncocytoma is ''chromophobe

renal cell carcinoma Renal cell carcinoma (RCC) is a kidney cancer that originates in the lining of the proximal convoluted tubule, a part of the very small tubes in the kidney that transport primary urine. RCC is the most common type of kidney cancer in adults, resp ...

oncocytic variant'', which like the renal oncocytoma has eosinophilic cytoplasm, but has perinuclear clearing and, typically, some degree of

nuclear atypia Nuclear atypia refers to abnormal appearance of cell nuclei. It is a term used in cytopathology and histopathology. Atypical nuclei are often pleomorphic. Nuclear atypia can be seen in reactive changes, pre-neoplastic changes and malignancy. S ...

Immunohistochemical profile

Cytokeratin Cytokeratins are keratin proteins found in the intracytoplasmic cytoskeleton of epithelial tissue. They are an important component of intermediate filaments, which help cells resist mechanical stress. Expression of these cytokeratins within epit ...

AE1/AE3 + *

Vimentin Vimentin is a structural protein that in humans is encoded by the ''VIM'' gene. Its name comes from the Latin ''vimentum'' which refers to an array of flexible rods. Vimentin is a type III intermediate filament (IF) protein that is expressed ...

- * EMA + *

CD10 Neprilysin (), also known as membrane metallo-endopeptidase (MME), neutral endopeptidase (NEP), cluster of differentiation 10 (CD10), and common acute lymphoblastic leukemia antigen (CALLA) is an enzyme that in humans is encoded by the ''MME'' ge ...

+/- * CK7 +/- parcellaire *

CK20 Keratin 20, often abbreviated CK20, is a protein that in humans is encoded by the ''KRT20'' gene. Keratin 20 is a type I cytokeratin. It is a major cellular protein of mature enterocytes and goblet cells and is specifically found in the gastric ...

- * CK19 - *

AMACR α-Methylacyl-CoA racemase (AMACR, ) is an enzyme that in humans is encoded by the ''AMACR'' gene. AMACR catalysis, catalyzes the following chemical reaction: :(2''R'')-2-methylacyl-CoA \rightleftharpoons (2''S'')-2-methylacyl-CoA In mammalian c ...

(

Racemase Epimerases and racemases are isomerase enzymes that catalyze the inversion of stereochemistry in biological molecules. Racemases catalyze the stereochemical inversion around the asymmetric carbon atom in a substrate having only one center of asymm ...

) - * S100 + *c-kit (

CD117 Proto-oncogene c-KIT is the gene encoding the receptor tyrosine kinase protein known as tyrosine-protein kinase KIT, CD117 (cluster of differentiation 117) or mast/stem cell growth factor receptor (SCFR). Multiple transcript variants encoding diff ...

) + * Cadherin-E + *

TFE3 Transcription factor E3 is a protein that in humans is encoded by the ''TFE3'' gene. Function TFE3, a member of the helix-loop-helix family of transcription factors, binds to the mu-E3 motif of the immunoglobulin heavy-chain enhancer and is e ...

- * CAM5.2 +

Treatment

Renal oncocytoma is considered

benign Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malign ...

, cured by

nephrectomy A nephrectomy is the surgical removal of a kidney, performed to treat a number of kidney diseases including kidney cancer. It is also done to remove a normal healthy kidney from a living or deceased donor, which is part of a kidney transplant pro ...

. There are some familial cases in which these tumors are multicentric rather than solitary.Robbins pathology, page 1015 However, they may be resected to exclude a malignant tumor, e.g.

Prognosis

The overall

five-year survival rate The five-year survival rate is a type of survival rate for estimating the prognosis of a particular disease, normally calculated from the point of diagnosis. Lead time bias from earlier diagnosis can affect interpretation of the five-year surviva ...

has been estimated to be 63%, with 100% disease-specific survival.

Additional images

Image:Renal oncocytoma2.jpg,

Micrograph A micrograph or photomicrograph is a photograph or digital image taken through a microscope or similar device to show a magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken on a mic ...

of a renal oncocytoma.

H&E stain Hematoxylin and eosin stain ( or haematoxylin and eosin stain or hematoxylin-eosin stain; often abbreviated as H&E stain or HE stain) is one of the principal tissue stains used in histology. It is the most widely used stain in medical diagnos ...

. Image:Renal oncocytoma4.jpg, Micrograph of a renal oncocytoma. H&E stain. Image:Renal oncocytoma (1).jpg, Micrograph of a renal oncocytoma. H&E stain. Image:Renal oncocytoma (2).jpg, Micrograph of a renal oncocytoma. H&E stain. Image:Renal oncocytoma (3).jpg, Micrograph of a renal oncocytoma. H&E stain. Image:Chromophobe renal cell carcinoma, eosinophilic variant - high mag.jpg, Micrograph of ''chromophobe RCC oncocytic variant'', the main differential diagnosis of renal oncocytoma.

References

External links

{{DEFAULTSORT:Renal Oncocytoma Benign renal neoplasms