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I have a cyst on my kidney — what do I do?
Kidney Health5 min read

I have a cyst on my kidney — what do I do?

A scan found a cyst on your kidney and nobody explained it. Here are the five steps that actually matter — starting with one line in your radiology report.

The scan wasn't even for your kidneys.

Maybe it was belly pain that turned out to be nothing much. Maybe a stone. Maybe a surgeon wanted imaging before an operation on something else entirely. Either way, a few days later a report lands in your patient portal, and somewhere in it is a sentence about a cyst on your kidney that nobody has called you about.

Then it's eleven at night and you're on your phone reading things that are making it worse.

I see some version of this most weeks. Here is the order I'd actually go in.

First: get the whole report, not the portal summary

Most portals show you the impression, which is the radiologist's two or three line conclusion at the bottom. The part you want is usually higher up, in the findings.

What you're looking for is a Bosniak category. Radiologists sort cystic kidney lesions on a scale of I to IV, revised in 2019. That number does more work than the size of the cyst, your symptoms, or anything anyone can feel on an exam.

CategoryWhat it means for you
IThin wall, fluid only. Not cancer. No follow-up imaging.
IIA few thin internal divisions or fine calcium. Not cancer. No routine follow-up.
IIFSlightly more complex. Needs repeat imaging on a schedule.
IIIThickened, irregular, enhancing features. Needs a urologist. Often surgical.
IVSolid enhancing components. Treated as kidney cancer until proven otherwise.

If your report names a category, you already have most of your answer. If it doesn't, that's a fair thing to ask about, and it's worth asking twice if your scan was an ultrasound.

There's more detail on how the categories are defined on our renal cysts page.

Second: know what your scan could actually see

Ultrasound is very good at one thing. It tells fluid from solid. For a plain, thin-walled, fluid-filled cyst, that is genuinely enough, and nothing further is needed.

What ultrasound can't do is show whether any part of a lesion takes up contrast dye. Enhancement is the finding that separates a harmless complex cyst from a cystic kidney cancer, and seeing it takes CT or MRI with contrast.

So if your ultrasound mentioned septations, a thickened wall, calcium, or solid areas, the next step is a different scan. Not the same scan again in six months.

One more thing. A lot of reports end with "clinical correlation recommended." That isn't filler. It means the radiologist has described what they see and someone still has to sit down with the images and with you.

Third: ignore what you've read about food

I want to be blunt here, because the internet isn't.

Nothing you eat or drink shrinks a kidney cyst. Not lemon water, not alkaline water, not dandelion root, not apple cider vinegar, not three liters a day. There is no study behind any of it.

Cysts don't work that way. They're lined with epithelium, they fill on their own schedule, and nothing that goes through your stomach reaches them.

When a cyst does disappear on a later scan, it had almost always bled or gotten infected and then reabsorbed. It wasn't the juice.

Diet does matter for your kidneys. Salt, blood pressure and blood sugar shape kidney function over decades, and that's worth a real conversation. It's just a completely different conversation from this one.

Fourth: work out which specialist you need

People lose weeks here, and they shouldn't have to.

Urologists operate. Draining a cyst, injecting it so it doesn't refill, removing it, taking out part or all of a kidney for a Bosniak III or IV lesion. Those are urologic procedures. If something has to come out, you want a urologist.

Nephrologists ask what it means. That's my side of it. Is this one finding or a pattern? Is your filtration rate where it should be? Is there protein or blood in the urine? Is your blood pressure doing something it shouldn't? Has anyone in your family been on dialysis?

One cyst on an otherwise healthy kidney in someone in their sixties is a genuinely different situation from four cysts across both kidneys in someone in their thirties. The second one is the appointment I want to see.

Fifth: ask your family some direct questions

If your scan showed cysts in both kidneys, and more than one or two, call a relative this week.

Has anyone needed dialysis. Has anyone had a transplant. Has anyone been told they have cysts, or been told they had "kidney trouble" that nobody ever properly explained.

That pattern raises the question of autosomal dominant polycystic kidney disease. It's inherited, it works on blood pressure and kidney function slowly over decades, and it matters for your siblings and your children as much as for you. It's diagnosed and managed by a nephrologist, and finding it early genuinely changes how the next thirty years go.

A lot of families carry this without ever having a name for it. Someone's father "had kidney problems." That is often exactly where the story starts.

When to stop reading and call someone

Short of that, get hold of the full report rather than the summary, and bring it to someone who will read all of it.

This article is for general education and is not a substitute for medical advice from your physician. If you have questions about your specific situation, contact a Remix Medical clinician.

Updated August 2, 2026. Medically reviewed by Uday Khosla, MD on August 2, 2026.

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