A renal oncocytoma

Oncocytoma

An oncocytoma is a tumor made up of oncocytes, a special kind of cells. -Presentation:An oncocytoma is an epithelial tumor composed of oncocytes, large eosinophilic cells having small, round, benign-appearing nuclei with large nucleoli....

is a tumour

Kidney tumour

Kidney tumours , also known as renal tumours, are tumours, or growths, on or in the kidney. These growths can be benign or malignant . They may be discovered on medical imaging incidentally Kidney tumours (or kidney tumors), also known as renal tumours, are tumours, or growths, on or in the kidney....

 of the kidney

Kidney

The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

 made up of oncocyte

Oncocyte

An oncocyte is an epithelial cell characterized by an excessive amount of mitochondria, resulting in an abundant acidophilic, granular cytoplasm...

s, a special kind of cell

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

.

Presentation

An oncocytoma is an epithelial tumor composed of oncocytes, large eosinophilic cells having small, round, benign-appearing nuclei

Cell nucleus

In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

 with large nucleoli.

Pathophysiology

Renal oncocytoma is thought to arise from the intercalated cells of collecting ducts of the kidney. It represent 5% to 15% of surgically resected renal neoplasms. Ultrastructurally, the eosinophilic cells have numerous mitochondria.

Diagnosis

In gross

Gross examination

Gross examination or "grossing" is the process by which pathology specimens are inspected with the bare eye to obtain diagnostic information, while being processed for further microscopic examination....

 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

Differential diagnosis

A differential diagnosis is a systematic diagnostic method used to identify the presence of an entity where multiple alternatives are possible , and may also refer to any of the included candidate alternatives A differential diagnosis (sometimes abbreviated DDx, ddx, DD, D/Dx, or ΔΔ) is a...

 of renal oncocytoma is chromophobe renal cell carcinoma

Renal cell carcinoma

Renal cell carcinoma is a kidney cancer that originates in the lining of the proximal convoluted tubule, the very small tubes in the kidney that filter the blood and remove waste products. RCC is the most common type of kidney cancer in adults, responsible for approximately 80% of cases...

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

Nuclear atypia

Nuclear atypia refers to abnormal appearance of cell nuclei. It is a term used in cytopathology. Specific abnormalities include pleomorphism....

.

Symptoms

Most cases of renal oncocytomas are asymptomatic, discovered incidentally (by chance) on a tomography

Tomography

Tomography refers to imaging by sections or sectioning, through the use of any kind of penetrating wave. A device used in tomography is called a tomograph, while the image produced is a tomogram. The method is used in radiology, archaeology, biology, geophysics, oceanography, materials science,...

 or ultrasound

Ultrasound

Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...

 of the abdomen. Some of the possible symptoms are: hematuria

Hematuria

In medicine, hematuria, or haematuria, is the presence of red blood cells in the urine. It may be idiopathic and/or benign, or it can be a sign that there is a kidney stone or a tumor in the urinary tract , ranging from trivial to lethal...

, flank pain, abdominal

Abdomen

In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

 mass.

Treatment

Renal oncocytoma is considered benign, cured by nephrectomy

Nephrectomy

Nephrectomy is the surgical removal of a kidney.-History:The first successful nephrectomy was performed by the German surgeon Gustav Simon on August 2, 1869 in Heidelberg. Simon practiced the operation beforehand in animal experiments...

. There are some familial cases in which these tumors are multicentric rather than solitary.

Renal oncocytoma are considered benign

Benign

A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...

; however, they may be resected to exclude a malignant tumor, e.g. renal cell carcinoma

Renal cell carcinoma

Renal cell carcinoma is a kidney cancer that originates in the lining of the proximal convoluted tubule, the very small tubes in the kidney that filter the blood and remove waste products. RCC is the most common type of kidney cancer in adults, responsible for approximately 80% of cases...

.