A urologist treats kidney cysts, particularly those causing symptoms or showing characteristics that suggest a risk of malignancy. A kidney cyst is a fluid-filled sac that forms on or in the kidney. Most cysts are harmless and require no treatment, but a small percentage can grow large, cause discomfort, or necessitate specialist attention. When a cyst requires physical intervention, such as drainage or surgical removal, the urologist leads the treatment.
Understanding Kidney Cysts
Kidney cysts are categorized into two main groups: simple and complex. Simple cysts are the most common type, characterized by thin, smooth walls and clear, watery fluid. These cysts are almost always non-cancerous, typically cause no symptoms, and are often found incidentally during imaging for unrelated concerns.
The distinction between cyst types is formalized using the Bosniak classification system. This system assigns a score from I to IV based on imaging features like wall thickness, internal partitions, and enhancement with contrast dye. A Bosniak I cyst is the simplest, carries virtually no risk of cancer, and requires only observation.
Complex cysts (Bosniak II-F, III, and IV) have irregular features, such as thickened walls, internal calcifications, or solid components. The risk of malignancy increases significantly with higher Bosniak scores. For example, a Bosniak III cyst has an estimated cancer risk up to 50%, and a Bosniak IV cyst is considered cancerous in most cases, requiring immediate surgical removal.
Defining the Roles: Urologist vs. Nephrologist
The management of kidney health often involves two specialists with distinct focuses. A urologist is a surgical specialist focused on the urinary tract and male reproductive system. Their expertise covers structural and anatomical issues of the kidneys, ureters, bladder, and urethra. Urologists address problems requiring physical or surgical correction, such as stones, blockages, or tumors.
A nephrologist, conversely, is a medical specialist who focuses on kidney function and manages systemic conditions impacting kidney performance. This includes chronic kidney disease, hypertension, fluid and electrolyte balance, and conditions like polycystic kidney disease. Nephrologists prescribe medications and manage treatments like dialysis, but they do not perform surgery.
The management path for kidney cysts depends on the cyst’s nature. A nephrologist may oversee the long-term medical management of patients with numerous simple cysts or monitor kidney function. However, the urologist is consulted when a cyst is large, symptomatic, or classified as complex (Bosniak II-F and above). Since intervention is structural, the decision to physically drain or remove the cyst falls to the urologist, even if the patient sees both specialists.
Urological Treatment and Management of Cysts
The urologist’s approach to a kidney cyst is guided by the Bosniak classification and whether the cyst is causing symptoms like pain, infection, or urinary tract obstruction. For many simple cysts, the initial step is active surveillance. This involves regular follow-up imaging, such as a CT scan or ultrasound, to monitor for changes in size or characteristics. Treatment is initiated only when the cyst causes a problem or has features concerning for malignancy.
A common minimally invasive procedure for a large, symptomatic simple cyst is aspiration and sclerotherapy. This technique involves inserting a fine needle through the skin and into the cyst, often guided by ultrasound or CT imaging. The fluid is drained, a process called aspiration, which immediately relieves pressure and associated pain.
Following aspiration, a sclerosing agent, commonly an alcohol solution like 95% ethanol, is injected into the empty cyst cavity. The purpose of this agent is to chemically irritate and destroy the cyst’s inner lining cells, causing the walls to stick together. This prevents fluid from re-accumulating, significantly lowering the recurrence rate compared to simple aspiration alone.
For complex cysts (Bosniak III and IV) or large, symptomatic simple cysts that recur after sclerotherapy, the urologist recommends laparoscopic decortication. This is a minimally invasive operation performed through small incisions using specialized instruments and a camera. The urologist surgically removes the outer wall of the cyst (deroofing), allowing the remaining lining to collapse and drain into the surrounding tissue.
Laparoscopic decortication provides a higher long-term success rate for preventing recurrence compared to aspiration, especially for large cysts or those pressing on other organs. Surgical removal of complex cysts also allows the urologist to send the cyst wall for pathological analysis. This step determines if cancerous cells are present, which informs further necessary treatment.