Kidney Cysts – What do You Need to Know

by Dr. Alex Shteynshlyuger, a board-certified urologist and specialist in the treatment of urinary problems in men and women including frequent urination, burning with urination and urinary retention.  

If you have any questions, to schedule a consultation or if you need a second opinion, please contact us or call: 646-663-4151

Treatment of Renal Cysts at New York Urology Specialists

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What are Renal Cysts?

A cyst is a sac containing water-like fluid. Renal cysts are small collections of fluid encased in a thin shell that form in the kidney. They are fairly common in older individuals and are present in 50 percent of people above the age of 50. They usually do not cause any symptoms. In fact, these pouches of fluid in the kidney may be discovered incidentally during routine examinations or investigations for other problems.

Simple Renal Cysts and Complex Renal Cysts

They are two types of kidney cysts – acquired kidney cysts which are typically not inherited and genetically inherited polycystic kidney disease. Renal cysts are classified as simple and complex.

Simple cysts are thin-fluid filled sacs that develop in many people as they age. Usually acquired simple renal cysts do not cause the kidneys to enlarge in size, and they do not lead to a reduction in kidney function.

Complex renal cysts have a thicker wall and may contain solid material. Complex renal cysts are more concerning because some of them may be cancerous.

What is the Cause of Renal Cysts?

We do not completely understand why these fluid-filled sacs develop. Men and women tend to develop small cysts in their kidneys as they age. It is believed that deficient blood supply, tubular obstruction, and weakening of the kidney surface may play a role. Simple renal cysts have a very low chance of causing any problems or leading to cancer. Complex kidney cysts need to be monitored with imaging to distinguish between benign and cancerous ones.

The board-certified urologists at New York Urology Specialists have extensive experience in evaluating and treating men and women with renal cysts. We also treat associated complications, such as pain, UTIs, and kidney stones. We offer surgical treatment to drain the cysts and prevent their recurrence.

Bosniac Grading of Renal Lesions

The Bosniak system classifies lesions in the kidneys into five categories based on features seen on CT imaging. This system is a good predictor of the risk of malignancy. It helps urologists in deciding the appropriate course of follow-up and treatment.

Bosniak 1: Round, simple cysts without a perceptible wall. These are almost never malignant. No workup or follow-up is required.

Bosniak 2: Well-marginated renal cysts with minimal complexity. They may require follow-up but still have a very low chance of being malignant.

Bosniak 2F: Lesions with more septae (divisions) and calcifications and usually more than 3 cm in size. They require follow-up. About 5 percent are malignant (cancerous).

Bosniak 3: Lesions with thick, nodular septae and measurable enhancement on contrast-enhanced CT. They require workup and treatment with partial nephrectomy (removal of a part of the kidney) or radiofrequency ablation in patients who cannot undergo surgery. Many of them are associated with cancer (approximately 30-55 percent of Bosniak 3 lesions are malignant).

Bosniak 4: These are complex renal cysts that are clearly malignant. Sometimes they appear like fluid-filled sacs, but are actually renal masses with a very high chance of cancer. The diagnosis is confirmed with biopsy. Biopsy-proven renal masses that are cancerous require surgery for removal. More than 85% of Bosniac 4 lesions are cancerous.

Symptoms of Renal Cysts

Most simple renal cysts do not cause any symptoms. They may slowly grow over time, but it is not necessary to monitor them with repeat studies. Patients with minimally complex (Bosniak 2F) lesions typically require annual follow-up with a kidney ultrasound and possibly MRI.

Sometimes kidney cysts may cause pain and discomfort due to their size or because of an infection. Other symptoms may include fever, changes in urinary habits, and blood in the urine. In this situation, treatment may be required. If infection is present, antibiotic treatment is usually effective. In patients with persistent pain, percutaneous drainage and ablation with sclerotherapy, or surgical decortication of the cyst may be beneficial.

Polycystic Kidney Disease

Polycystic kidney disease (PKD) is an inherited disorder that predisposes a person to developing multiple kidney cysts. These are different from simple cysts. They cause damage to the renal tissue and enlargement in the size of the kidneys. Polycystic kidney disease is associated with a risk for developing high blood pressure, renal failure, and brain aneurysms. It is important for patients who have a history of polycystic kidney disease to be identified and monitored periodically. Symptoms of PKD include pain, hypertension, hematuria, and UTIs.

Autosomal Recessive PKD

Patients with multiple bilateral cysts identified at a young age are likely to have autosomal recessive polycystic kidney disease (ARPKD). In fact, babies with ARPKD may show signs of the disease within the first few months of life. People with this form of the disorder have cysts seen in the kidney as well as in other organs, for example, the liver and epididymis.

Diagnosis of ARPKD in at-risk individuals between 15 and 30 years of age is made when at least two unilateral or bilateral kidney cysts are present. In individuals between 30 and 59 years of age, two cysts in each kidney should be present to qualify as ARPKD. In individuals older than 60 years, at least four cysts in each kidney are needed to make a diagnosis.

Autosomal Dominant PKD

In patients with ADPKD, cysts are present only in the kidneys. They are usually discovered when the individual is an adult (typically between 30 and 50 years of age).

Diagnosis of Kidney Cysts

Simple fluid-filled sacs in the kidneys are usually discovered incidentally during imaging studies for other reasons. When one or more cysts are discovered in the kidneys, further imaging may be required to differentiate between benign and malignant lesions. The urologist may order an ultrasound, MRI, or CT scan to distinguish harmless lesions from more serious and potentially cancerous ones.

Treatment of Renal Cysts


No treatment is needed for simple kidney cysts that are not causing any symptoms. The urologist may choose to observe cysts that are minimally complex periodically with ultrasound or MRI.

Sclerotherapy of Kidney Cysts

If a patient is experiencing symptoms such as pain and discomfort, treatment may be required. A procedure called sclerotherapy may be recommended. This involves draining the cyst with a fine needle under ultrasound-guidance. Alcohol is then instilled into the area to harden up the tissue. This is an outpatient procedure that is done under local anesthesia. The cysts can recur in up to 50 percent of cases following sclerotherapy.

Renal Cyst Decortication

For larger cysts or cysts that recurred after sclerotherapy, surgery is required. This is mostly done in a minimally invasive manner with 3-4 tiny incisions in the abdominal area or a single incision in the belly button. The surgeon drains the cyst and dissects it away from surrounding structures. The outer tissue is burned away and a drain is left in place for a few days. Cure rates with decortication are up to 95 percent. The laparoscopic approach is associated with a shorter hospital stay (1-2 days), less pain, faster recovery, and a better cosmetic result compared to an open surgical approach.

Treatment of Kidney Cysts at New York Urology Specialists

At New York Urology Specialists, we use renal ultrasound for evaluation and management of kidney cysts. If necessary, a renal MRI is used to evaluate multiple cysts, especially in patients with polycystic kidney disease. Patients who develop UTIs are treated with antibiotics. Patient with large symptomatic kidney cysts that are causing persistent or recurrent flank pain may require percutaneous drainage or decortication.


Why Choose New York Urology Specialists for Treatment of Kidney Cysts?

  • All treatment is performed by a Board-certified urologist experienced in treating men with symptoms of frequent urination, urinary urgency, urinary incontinence and bladder pain using medical therapy, minimally invasive therapies, lasers, and open surgery.
  • We are one of the few practices in the region to offer a full range of options for treatment of urinary problems in men and women
  • We offer treatment options for overactive bladder, UTI, and urinary incontinence in our office which avoids the risks, costs, and recovery from general anesthesia.  
  • Extensive Experience: Hundreds of men and women have treated successfully using medical therapy, Botox for overactive bladder, Interstim for frequent urination and tibial neuromodulation.

Excellence-Urology_Care VasectomyWhen it comes to experience and innovation – New York Urology Specialists are a step ahead.  Better Science Means Better Care.  We specialize in minimally invasive highly effective treatment for symptoms of bladder pain, urethral burning, pelvic discomfort, incomplete bladder emptying, urinary frequency, and urgency. Many treatment procedures are performed in the convenience and privacy of office settings under local anesthesia.

If you have any questions, to schedule a consultation or if you need a second opinion, please contact us or call: 646-663-4151

Medicare and major insurances accepted.   We offer affordable rates and financing options.

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Call today: 646-663-4151 or make an appointment online

Dr. Alex Shteynshlyuger is a fellowship trained board-certified urologist with expertise in evaluation and treatment of urinary problems.  He uses modern effective and proven treatment methods including Botox for OAB, Interstim neuromodulation.  He is highly recommended by top primary care physicians in the New York area.

He has successfully treated hundreds of men and women of all ages with urinary problems including bladder problems, kidney problems, urethral and ureteral problems. 

If you or someone you know has been experiencing urological symptoms, make an appointment to take advantage of Dr. Shteynshlyuger’s expert advice. Please feel free to contact us with any questions.


If you have any questions, to schedule a consultation or if you need a second opinion, please contact us or call: 646-663-4151

We offer affordable, highest-quality urology care with or without insurance.   Find out our office hours or directions to our office. We offer weekday, weekend, and evening office hours.

If you have any questions, to schedule a consultation or if you need a second opinion, please contact us or call: 646-663-4151

Dr. Alex Shteynshlyuger is a board-certified urologist in NYC who specializes in treating men and women with urinary problems including frequent urination, difficulty emptying the bladder, urinary urgency and incontinence.