Benign kidney tumors may not always produce symptoms. Usually, people receive a diagnosis when undergoing tests for another reason. Symptoms, if they occur, may include blood in the urine and a mass or pain in the side.

Doctors may use diagnostic tools such as physical exams, blood tests, urinalysis, biopsy, and imaging if they suspect a person has a kidney tumor or tumors. They base the decision about surgical removal on several factors, such as the size and number of tumors.

There are many types of benign kidney tumors, but this article will discuss only two types: angiomyolipomas and oncocytomas.

This article will mainly discuss the symptoms of these benign kidney tumors, as well as diagnosis and treatment. It will also examine the symptoms of a cancerous kidney tumor.

A person putting their hands on their hips due to kidney pain, which can be a sign of a benign kidney tumor -1.Share on Pinterest
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A benign kidney tumor is a noncancerous mass in the kidney. While these tumors can grow and cause difficulties, they do not spread to other parts of the body.

There are several types of benign kidney tumors. Angiomyolipomas are the most common, and they occur more frequently in females. Oncocytomas are not common and happen more often in males.

Angiomyolipoma symptoms

According to a 2018 review, most angiomyolipoma tumors have not caused symptoms at the time of diagnosis.

However, sometimes these tumors can produce the following:

Oncocytoma symptoms

As with angiomyolipomas, oncocytomas usually do not produce symptoms at diagnosis. If they do, a person can experience:

  • profuse bleeding
  • flank pain
  • a mass in the flank

Learn more about kidney masses.

Doctors often detect benign kidney tumors before they cause symptoms. The detection tends to be incidental, which means it happens when a person has tests to diagnose another health condition.

In cases where a doctor suspects a kidney tumor, some common diagnostic tools they use include:

Imaging may involve a CT scan, in which masses with a high fat content indicate a benign tumor. Masses with a low fat content suggest cancer.

A 2018 review notes that ultrasound imaging can help screen for kidney tumors without the need for specific preparations that some other forms of imaging require.

If someone has an angiomyolipoma that is not causing symptoms, a doctor may often choose to monitor it closely before attempting any treatment. However, if it begins to produce symptoms — such as bleeding or pain — treatment may be necessary.

Options may include many of the same choices that exist for cancerous tumors, such as surgical removal or radiofrequency ablation, which involves using heat to destroy the tumor. Doctors may choose ablation if an individual is not a candidate for surgery.

Although an oncocytoma can grow very large, this type of tumor does not typically spread to other organs, so surgery is a frequent cure.

Various factors determine whether a tumor requires removal and, if so, what type of procedure may be best. These include:

  • the size and number of tumors
  • a person’s symptoms
  • whether tumors are in one or both kidneys
  • the person’s overall health

A cancerous tumor may cause some of the same symptoms as a benign tumor, such as:

  • blood in the urine
  • a mass in the flank
  • flank pain

Other symptoms may include:

About one in four kidney tumors are benign.

Learn more about the symptoms of kidney cancer.

Several types of benign kidney tumors exist. Symptoms include blood in the urine and pain or a palpable mass in the flank. However, doctors often find these tumors when people undergo tests for another condition. At this point, they usually produce no symptoms.

Doctors may perform a full diagnostic workup if they suspect someone has a benign kidney tumor. A CT scan that shows a mass with a high fat content may suggest a benign rather than a cancerous tumor.

If a tumor is small and not causing symptoms, a doctor may just monitor it, but surgical removal or destruction with radiofrequency ablation is sometimes necessary. A cancerous kidney tumor may cause the same symptoms as a benign tumor, as well as loss of appetite, unintended weight loss, and recurring fevers.