Are kidney cysts truly benign?

According to Dr. Tran Quoc Phong, MSc, Head of the Urology Unit at An Binh Hospital (Ho Chi Minh City), not every “cyst” found in the kidney is harmless. A significant proportion of these lesions may actually represent suspicious cystic kidney tumors that require close monitoring or early intervention to preserve renal function and prevent malignant transformation.

At An Binh Hospital, the number of patients referred for “kidney cysts” that are later identified as cystic renal tumors has been increasing. These lesions initially resemble simple cysts but possess more dangerous characteristics—such as thickened walls, calcifications, increased vascularity, or solid components—suggestive of cystic renal cell carcinoma, a malignant form that is often difficult to detect through conventional ultrasound.

Dr. Phong explains that most simple kidney cysts are benign and require no treatment beyond periodic monitoring. However, many patients do not understand the difference between simple cysts and cystic lesions suspicious for cancer. Even ultrasound imaging is sometimes insufficiently detailed to make an accurate distinction. Many cases require contrast-enhanced CT scans or MRI to evaluate the complexity of the cyst and assess cancer risk.

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Many patients seek care too late, increasing the risk of complications

Dr. Phong recalls receiving patients who brought ultrasound results from the previous year showing only a “kidney cyst.” However, upon re-examination at An Binh Hospital, the lesion had developed abnormal septations, wall thickening, and increased blood flow—high-risk features for kidney cancer. In some cases, the tumor had grown large enough to require partial nephrectomy to completely remove the lesion while preserving as much healthy kidney tissue as possible.

For complex or cancer-suspected cystic lesions, nephron-sparing surgery is the preferred approach, especially when the tumor is still small. This technique requires high surgical expertise, as the surgeon must remove all malignant tissue while preserving the remaining normal kidney. If discovered late—when the tumor has grown or invaded surrounding structures—patients may be forced to undergo total nephrectomy, a regrettable outcome that could have been prevented with earlier detection.

One major challenge is patient complacency. Many people assume that any “kidney cyst” must be benign and therefore skip follow-up appointments. Others worry about cost or fear CT scans, leading to vague or inconsistent monitoring. Some even rely on folk remedies, herbal treatments, or hope that the cyst will disappear on its own—something Dr. Phong emphasizes has no scientific basis whatsoever.

“There is no natural remedy that can dissolve a kidney cyst or prevent kidney cancer,” Dr. Phong stresses. “A cyst is an anatomical structure—it cannot ‘disappear’ with herbal teas or traditional home treatments. The most important step is correct classification from the beginning. Benign cysts only require monitoring; suspicious lesions must be treated promptly.”

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Silent progression highlights the importance of regular health check-ups

Experts warn that cystic renal cancer often causes no symptoms in its early stages. Patients typically experience no pain, no blood in the urine, and no obvious warning signs. Tumors are often discovered incidentally during ultrasound examinations, or only after they grow large enough to cause back pain, fatigue, or weight loss. This makes regular health screenings especially important, as kidney ultrasound is a simple, low-cost test that is highly effective in detecting early abnormalities.

“Any abnormal lesion in the kidney, even very small, needs proper monitoring,” Dr. Phong advises. “Patients must return for follow-up as scheduled, avoid delaying appointments, and undergo recommended imaging tests. A few months of neglect is enough for a benign cyst to evolve into a complex lesion that is far more difficult to treat.”