Kidney tumors can be benign or malignant, with different types including renal adenoma, renal oncocytoma, angiomyolipoma, fibroma, and lipoma. Malignant tumors most commonly arise from renal cell carcinoma, with clear cell RCC being the most common. Other types of malignancies include Wilms tumor, transitional cell carcinoma, and renal sarcoma. Treatment options include surgical removal, chemotherapy, and radiation.
A kidney tumor is a swelling or lesion in the kidney that occurs due to abnormal cell growth. The kidney is a paired organ in the back, or rear, part of the abdomen that is responsible for urine production, blood filtration, and reabsorption of necessary water, salts, and sugars into the bloodstream, among other functions. There are different types of kidney tumors, which can be benign or malignant. If the tumor is benign, it is not cancerous and does not metastasize, spread to other tissue, or grow uncontrollably. If the tumor is malignant, it gets progressively worse due to abnormal growth and spreads to other tissues via blood, lymph, or direct invasion.
Benign renal tumors include renal adenoma, renal oncocytoma, angiomyolipoma, fibroma, and lipoma. Although renal adenomas are small and benign, they closely resemble malignant renal cell carcinoma (RCC) cells and are widely considered precancerous. Like renal adenomas, renal oncocytomas are also considered precancerous, look like RCC cells under a microscope, and usually have no symptoms. Unlike renal adenomas, renal oncocytomas are not exclusive to the kidney and often grow large. To prevent the development of cancer, doctors usually recommend surgical removal of both renal adenomas and renal oncocytomas if the patient’s general health permits.
An angiomyolipoma, also called a renal hamartoma, is a benign tumor resulting from a rare genetic mutation that usually occurs in middle-aged women. While not precancerous, a large angiomyolipoma is potentially fatal if it ruptures. If this tumor is large, starting to grow, or has symptoms, doctors will likely recommend surgical removal or an arterial embolization procedure.
A fibroid is another rare benign tumor of the kidney, more common in women. This tumor is often asymptomatic, occurs at the edge of the kidney and resembles malignant tumors. Because it’s difficult to diagnose whether the tumor is malignant or benign, doctors often recommend surgical removal. Lipomas are also rare and more common in middle-aged women. This cancer affects the fat cells in the kidney, can have symptoms of regional pain and blood in the urine, and can be precancerous.
Malignant tumors most commonly arise from a cancer called renal cell carcinoma (RCC), which originates in the proximal tubule epithelium in the nephron of the kidney. The types of malignant tumors are classified according to the appearance of the cancerous cells under a microscope. The four specific types are clear cell renal cell carcinoma, papillary renal cell carcinoma, chromophobe renal cell carcinoma, collecting duct. RCCs that do not fit the characteristics of these four types are called unclassified renal cell carcinomas. Surgical removal in a procedure known as a nephrectomy is recommended for all types of RCC when the tumor is limited to the kidney.
Clear cell RCC is by far the most common. The cells of these tumors appear pale or clear under a microscope. Papillary RCC shows finger-like projections from the cancerous cells and is divided into two groups, type I and type II. Type II is more likely to metastasize. The cells of chromophobic RCC resemble clear cell RCC, but usually metastasize less than clear cell RCC. Collecting duct carcinoma is very rare, very aggressive, and resembles papillary RCC.
Other types of malignancies include Wilms tumor, transitional cell carcinoma, and renal sarcoma. Wilm’s tumor, also known as nephroblastoma, is a fairly rare cancer that affects young children. This kidney cancer can spread to other tissue, but is highly treatable with methods such as surgery, chemotherapy, and radiation.
Transitional cell carcinoma is cancer of the kidney that originates in the renal pelvis, where the kidney articulates with the ureter. This tumor is probably caused by cigarette smoking and is treated with nephrectomy, chemotherapy, and radiation. Nephrectomy is the first line of treatment and usually includes surgical removal of the affected kidney, ureter, and part or all of the bladder.
A renal sarcoma is a rare tumor that affects the connective tissue of the kidney. This kidney tumor may have symptoms of blood in the urine, a palpable lump in the abdomen, and lower back pain. If the kidney tumor is localized and the patient can handle surgery, doctors will likely recommend nephrectomy. Chemotherapy and radiation may also be used.
Protect your devices with Threat Protection by NordVPN
