From the Guidelines
The presence of lymph nodes in the fat anterior or lateral to the psoas muscle caudal to the lower pole of the left kidney is a common site for lymph node metastasis in kidney cancer.
Background
Renal cell carcinoma (RCC) typically spreads via lymphatic and hematogenous routes, with regional lymph node involvement being a significant pattern of metastasis. The retroperitoneal lymph nodes, particularly those around the renal hilum, para-aortic, and paracaval regions (which include the area anterior and lateral to the psoas muscle below the kidney), are primary sites for lymphatic spread from kidney tumors.
Key Points
- The anatomical region contains important lymphatic drainage pathways from the kidney.
- Left-sided kidney tumors often metastasize to lymph nodes along the left renal vein, para-aortic chains, and the area around the psoas muscle.
- The presence of enlarged or abnormal lymph nodes in this location should raise suspicion for metastatic disease in patients with known kidney cancer and warrants careful evaluation during staging and follow-up imaging, as noted in studies evaluating the accuracy of CT in detecting metastatic retroperitoneal lymph nodes 1.
Imaging Considerations
- CT is the reference standard imaging test used for assessing the retroperitoneum for the presence of metastatic lymphadenopathy, providing excellent imaging assessment of the para-aortic and paracaval regions 1.
- Lymph nodes >1 cm in short axis are highly suspicious for metastatic disease, particularly if they are located in the hilar regions of the kidney or in the para-aortic or caval areas 1.
- The use of iodinated IV contrast media, as well as oral contrast media, may aid in detection of retroperitoneal lymph nodes, clarifying the adjacent normal anatomic structures including blood vessels and the duodenum 1.
From the Research
Lymph Node Metastasis in Kidney Cancer
- The provided studies do not directly address the commonality of lymph node metastasis in the fat anterior or lateral to the psoas muscle caudal to the lower pole of the left kidney in kidney cancer 2, 3, 4, 5, 6.
- However, it is known that metastasis to lymph nodes is a common feature of disease progression in most solid organ malignancies, including kidney cancer 3.
- The location of lymph node metastasis can vary, but there is no specific information available in the provided studies regarding the fat anterior or lateral to the psoas muscle caudal to the lower pole of the left kidney.
- Studies have reported on the imaging features of neoplastic iliopsoas masses and the association with other metastatic sites in the abdomen, but these do not provide direct evidence on the commonality of lymph node metastasis in the specified location 4.
- Other studies have focused on the diagnostic value of apparent diffusion coefficient of psoas muscles for evaluating complications in patients with Crohn's disease, which is not directly relevant to the question of lymph node metastasis in kidney cancer 6.