What is a Renal Mass?

A renal mass is a growth on or in the kidney. Such masses are often diagnosed during radiological examination of the kidneys or surrounding area, which may be conducted for a variety of reasons. When a renal mass is identified, it is important to evaluate it to determine whether or not additional medical steps need to be taken. Such masses may be benign or malignant, and there are a number of treatment options available to deal with them.

Sometimes symptoms of kidney problems lead a doctor to order an ultrasound or similar medical imaging study of the kidneys to look for abnormalities. These symptoms can include difficulty urinating, frequent urination, tenderness in the abdomen, and electrolyte imbalances in the blood. In these instances, a mass will show up during the imaging study, and can be viewed in very clear detail with studies such as MRIs. In other instances, the mass is identified during a study for unrelated reasons in which kidney abnormalities are observed by the radiologist.

A mass on the kidney can take the form of a cyst, in which case it is generally filled with fluid and may contain some detritus, or it can be a solid growth. Benign tumors do sometimes occur in the kidneys, but a solid growth is more commonly a sign of a malignancy which should be addressed. If the imaging study suggests that the mass is solid, a doctor may recommend a biopsy to take a sample of the mass for analysis in a pathology laboratory. The analysis can be used to determine which kinds of cells are involved in the mass.

A cancerous renal mass usually needs to be removed. Removal of the entire kidney may be recommended, or it may be possible to perform an operation which preserves part of the kidney, depending on the size and position of the mass. Additional treatment such as radiation and chemotherapy can be used to kill malignant cells in the hopes that the mass will not recur after these treatments.

If the renal mass appears to be benign, a doctor may recommend monitoring of the mass. Benign masses can still interfere with kidney function and cause other health problems, which can make them a cause for concern. Ultimately, a patient may require dialysis or kidney transplant to replace a failing kidney if the mass grows large enough or impinges upon a key area of the kidneys.