From the Guidelines
A small lesion in the fat anterior to the psoas muscle below the lower pole of the left kidney shortly after a partial nephrectomy for stage 1 Renal Cell Carcinoma (RCC) is concerning and warrants further evaluation, though it may not necessarily represent metastatic disease. According to the American College of Radiology's 2021 update on post-treatment follow-up and active surveillance of clinically localized renal cell carcinoma 1, radiologic imaging is the most useful component of surveillance, as most relapses and cases of disease progression are identified when patients are asymptomatic.
Key Considerations
- The location described could represent a reactive lymph node, post-surgical change, or normal anatomic variant rather than metastasis.
- Stage 1 RCC generally has a low risk of metastasis (less than 10%), making lymph node involvement less likely in this scenario.
- Several factors should be considered when evaluating this finding, including the lesion's size, enhancement pattern, and whether it was present on pre-operative imaging.
Recommended Approach
- I recommend obtaining a dedicated MRI with contrast of the abdomen and pelvis to better characterize the lesion, followed by possible biopsy if the imaging features are suspicious.
- Close surveillance with follow-up imaging in 3-6 months would be appropriate to assess for any changes in size or characteristics.
- Discussing these findings with a multidisciplinary team including your urologist, radiologist, and possibly an oncologist would help determine the most appropriate management approach, as suggested by the guidelines for follow-up of patients with treated or untreated RCC 1.
From the Research
Concerns for Metastatic Lymph Node
- A small lesion in the fat anterior to the psoas muscle below the lower pole of the left kidney shortly after a partial nephrectomy may be concerning for a metastatic lymph node in a patient with stage 1 Renal Cell Carcinoma (RCC) 2, 3.
- The presence of such a lesion could indicate the spread of cancer, which is a common occurrence in patients with RCC, especially in those with a history of partial nephrectomy 4, 5.
Diagnostic Considerations
- The use of imaging modalities such as FDG PET-CT can help diagnose the recurrence of RCC and identify potential metastatic sites, including lymph nodes 2.
- However, the accuracy of these imaging modalities may vary, and further evaluation, such as histological examination, may be necessary to confirm the diagnosis 2, 3.
Treatment and Prognosis
- The treatment and prognosis for patients with metastatic RCC depend on various factors, including the extent of disease, the presence of metastatic sites, and the patient's overall health 6, 4, 5.
- In some cases, partial nephrectomy may be considered as a cytoreductive procedure to reduce tumor burden and improve patient outcomes 6, 5.
- However, the decision to perform partial nephrectomy in the setting of metastatic RCC should be made on a case-by-case basis, taking into account the patient's individual circumstances and the potential benefits and risks of the procedure 6, 5.