From the Research
Metastatic lymph nodes from low-grade Renal Cell Carcinoma (RCC) can occur in the retroperitoneal space, including the area anterior to the psoas muscle below the lower pole of the left kidney, but this specific location is not among the most common sites for RCC metastasis. RCC typically metastasizes first to regional lymph nodes in the renal hilum and para-aortic region, then potentially to distant sites like lungs, bone, liver, and brain. The retroperitoneal lymphatic drainage patterns of the kidneys make hilar, paracaval, and para-aortic nodes the primary sites for lymphatic spread. While metastasis to lymph nodes in the fat anterior to the psoas muscle can occur, especially with left-sided tumors that may spread along the left-sided lymphatic channels, it would be considered less common than metastasis to the hilar and para-aortic nodes.
Key Points to Consider
- The likelihood of metastasis increases with higher grade tumors, larger primary tumors, and those with venous invasion 1.
- Any suspicious lymph node in this region in a patient with known RCC should be evaluated with appropriate imaging and potentially biopsy for definitive diagnosis.
- It is essential to note that not all enlarged lymph nodes are due to metastases, as inflammatory changes and/or follicular hyperplasia can also cause enlargement, especially in the presence of tumor necrosis 2.
- The treatment options for metastatic RCC have evolved, with combinations of immune checkpoint inhibitors or the combination of immune checkpoint inhibitors with tyrosine kinase inhibitors showing promising results 3, 1.
Clinical Implications
- Clinicians should be aware of the potential for metastatic RCC in unusual locations, even in the absence of a known primary kidney lesion 4.
- A thorough evaluation, including imaging and potentially biopsy, is necessary to determine the presence of metastatic disease.
- The choice of treatment for metastatic RCC depends on various factors, including the patient's overall health, the extent of the disease, and the presence of specific biomarkers 3, 1.