A solid kidney mass is one which is composed of solids tissues that do not represent fluid like in cysts.
How is a solid kidney mass diagnosed?
Solid masses of the kidney are often diagnosed on imaging studies like ultrasound, CT and MRI.
A mass of the kidney often needs a CT or MRI with and without contrast for definitive diagnosis.
Symptoms of a solid renal mass
They can be asymptomatic. When there are symptoms, they can consist of pain and urinary symptoms. Cancer can lead to weight loss, fatigue and feeling unwell in addition to urinary symptoms.
How does contrast help us determine a kidney mass is solid?
The idea is that a solid or cancerous mass will take up the contrast given into your vein. The solid mass will enhance or become brighter after the contrast is administered. Solid tissues receive blood and contrast goes where blood goes. Cysts or water filled masses don’t have blood enter internally so they stay the same after contrast is administered.
Solid kidney mass causes
Solid masses of the kidney are concerning for cancer and will often be removed. Simple cysts will be left alone. The distinction between solid and cystic masses of the kidney is therefore of most importance.
Solid masses are often renal cell carcinomas or cancers of the kidney. They can also be cancers of the collecting system where urine is collected. These are called transitional cell cancers.
Is a solid kidney mass always cancer?
No, solid masses can also be benign, but can not always be diagnosed before surgery. One example is an oncocytoma which can look like a renal cell cancer. Another is an angiomyolipoma.
Can a solid mass spread to other parts of the body?
Once a solid mass is diagnosed the radiologist will see if it has spread. Tumors of the kidney can spread into the vein of the kidney and inferior vena cava.
Tumors can also spread to lymph nodes, bones, and organs such as the liver. This is important to identify as the treatment will often change.
Solid kidney mass on Ultrasound
Ultrasound is an often used test to look at the kidneys and kidney masses. Ultrasound is very good at telling if a kidney mass is suspicious for cancer or if it’s simply a cyst filled with fluid.
Ultrasound may be ordered after your doctor detects blood in the urine or after another test like a CT identifies a kidney mass which needs to be further evaluated.
On ultrasound, a kidney mass that is solid and suspicious will not meet the criteria for a cyst or fluid filled mass. The internal contents may appear partially cystic or complex. There may sometimes be internal blood flow which cysts do not have.
The larger the size, the easier the distinction is made between cysts and solid masses. Small less than 1 cm lesions may be difficult to characterize on ultrasound. The exam may also be limited in obese patients.
Solid kidney mass on CT and MRI
A CT and MRI allows us to determine whether there is enhancement or solid components in the mass. A CT or MRI with and without contrast placed into your vein is done.
The idea is that the contrast will make any solid areas appear brighter indicating that the mass is not simply a cyst. A cyst only has fluid inside so it should not enhance or become brighter after administering contrast.
Solid kidney mass treatment
Referral to a urology doctor will be needed for surgery. He will determine whether your entire kidney or part of it needs to be removed.
If the tumor has spread, then an oncologist will be needed for chemotherapy treatment.
Often patients will get follow up imaging after surgery to make sure the tumor hasn’t come back or spread. Follow up imaging is also done for patients who’s tumor has spread to see how they are responding to treatment.
Solid kidney mass on imaging: summary
Solid kidney masses are composed of solid tissues instead of fluid like a cyst. Solid masses are more concerning for kidney cancer. They are diagnosed using imaging studies. We can not be certain they represent cancer or a benign diagnosis until they are resected surgically.