What is the workup for an exophytic (growth protruding outward) mass on the kidney?

From the Guidelines

The workup for an exophytic growth on the kidney should begin with a comprehensive imaging evaluation, typically starting with a contrast-enhanced CT scan of the abdomen and pelvis, as recommended by the most recent guidelines 1. This approach is supported by the American Urological Association (AUA) guidelines, which emphasize the importance of individualized counseling and management for patients with clinically localized renal masses 1. The initial imaging evaluation provides detailed information about the size, location, and characteristics of the growth, which is crucial for determining the next steps in management. For lesions larger than 1 cm, a dedicated renal protocol CT or MRI with and without contrast is recommended to better characterize the mass, as suggested by the ACR Appropriateness Criteria 1. Laboratory tests, including urinalysis, complete blood count, comprehensive metabolic panel, and renal function tests, should also be performed to assess the patient's overall health and renal function. If the imaging suggests a solid mass, particularly if it's larger than 4 cm or has concerning features like irregular borders or heterogeneous enhancement, a urologic consultation is warranted for consideration of biopsy or surgical intervention, as recommended by the AUA guidelines 1. For smaller lesions (less than 1 cm) that appear benign (like simple cysts), follow-up imaging in 6-12 months may be appropriate, as suggested by the ACR Appropriateness Criteria 1. The approach varies based on patient factors, including age, comorbidities, and renal function, and should be individualized to ensure optimal outcomes. Key considerations in the workup and management of exophytic renal growths include:

• The potential for malignancy, particularly renal cell carcinoma, which requires prompt intervention for optimal outcomes
• The importance of preserving renal function and minimizing morbidity
• The role of active surveillance and follow-up imaging in managing small renal masses
• The need for individualized counseling and management based on patient factors and tumor characteristics. Overall, a comprehensive and individualized approach to the workup and management of exophytic renal growths is essential for optimizing outcomes and minimizing morbidity and mortality, as emphasized by the most recent guidelines 1.

From the Research

Exophytic Growth on Kidney Workup

• The workup for exophytic growth on the kidney typically involves imaging studies to determine the size and location of the tumor, as well as its potential impact on kidney function 2.
• A study published in the Journal of Endourology found that exophytic renal tumors are more likely to be of lower pathologic grade and of the papillary RCC subtype when compared with endophytic renal tumors 2.
• Computer-aided detection systems have been developed to detect exophytic renal lesions on non-contrast CT images, with a reported sensitivity of 95% and 15 false positives per patient 3.

Surgical Management

• The surgical management of exophytic growth on the kidney typically involves either partial nephrectomy or radical nephrectomy, with the choice of procedure depending on the size and location of the tumor, as well as the patient's overall health 4, 5.
• A study published in the European Urology journal found that partial nephrectomy is not associated with markedly improved survival compared with radical nephrectomy for patients with cT1 renal cell carcinoma 5.
• A systematic review published in the Cochrane Database of Systematic Reviews found that partial nephrectomy may be associated with a decreased time-to-death of any cause, but appears to result in little to no difference in terms of surgery-related mortality, cancer-specific survival, and time-to-recurrence 6.

Diagnostic Considerations

• The diagnosis of exophytic growth on the kidney typically involves a combination of imaging studies, including CT and MRI, as well as biopsy and histopathological examination 2, 3.
• The use of computer-aided detection systems can help improve the accuracy of diagnosis and reduce the risk of false positives 3.
• The choice of surgical procedure will depend on the size and location of the tumor, as well as the patient's overall health and kidney function 4, 5.