Renal oncocytoma

Renal oncocytoma is a benign (noncancerous) growth of the kidney. They generally do not cause any signs or symptoms and are often discovered incidentally (by chance) while a person is undergoing diagnostic imaging for other conditions. Some people with renal oncocytoma will have abdominal or flank pain; blood in the urine; and/or an abdominal mass. Although these tumors can occur in people of all ages, they most commonly develop in men who are over age 50. The exact underlying cause of most isolated (single tumor affecting one kidney) renal oncocytomas is unknown; however, multiple and bilateral (affecting both kidneys) renal oncocytomas sometimes occur in people with certain genetic syndromes such as tuberous sclerosis complex and Birt-Hogg-Dube syndrome.^[1][2] Although many benign tumors do not require treatment unless they are causing unpleasant symptoms, it can be difficult to confidently differentiate a renal oncocytoma from renal cell carcinoma. Most affected people are, therefore, treated with surgery which allows for confirmation of the diagnosis.^[3][4]

Though there does not appear to be a consensus in the medical literature, we did identify several retrospective studies reporting the range of tumor sizes in included subjects. This information may be lacking as oncocytoma are typically managed with surgery as part of the diagnostic process and/or once symptoms are present.^[1] The largest measurement we found in our review was 16 cm, although many of the studies reported a tumor measurement between 8-11 cm as the largest.^{[1][5][6][7][8]}

Management of renal oncocytoma varies on a case-by-case basis. While studies suggest that most individuals with renal oncocytoma report symptoms once tumor size is greater than 5 cm, there are several factors taken into account when considering management options. These factors might include: manifesting symptoms, tumor growth rate, existing comorbidities, and the development of metastasis. ^[1][5] We would recommend that you discuss your concerns with your physicians as they are aware of your medical history and whether the renal oncocytoma is progressing.

Most renal oncocytomas are benign (non-cancerous) and metastasis is very rare. Although many benign tumors do not require treatment unless they are causing unpleasant symptoms, it can be difficult to confidently differentiate a renal oncocytoma from renal cell carcinoma based on diagnostic imaging tests alone. Most people are, therefore, treated with surgery which allows for confirmation of the diagnosis. If a renal oncocytoma is strongly suspected prior to surgery, a more conservative procedure such as a partial nephrectomy, may be performed.^[4][3]