From the Research
The fat anterior to the psoas muscle below the lower pole of the left kidney is not typically considered part of the primary lymphatic drainage pathway for left kidney cancer metastasis. Left renal cancer primarily drains to the left renal hilar, para-aortic, and left para-aortic lymph nodes, which are located more medially and superiorly. The area you're describing, anterior to the psoas below the kidney's lower pole, contains retroperitoneal fat that may include some scattered lymph nodes, but these are not the main nodes involved in the initial spread of left renal cell carcinoma. The primary lymphatic drainage of the left kidney follows a predictable pattern along the left renal vein toward the aorta and then up and down along the para-aortic chains, as supported by studies on lymph node metastases in renal cell carcinoma 1. This anatomical understanding is important for surgical planning and lymph node dissection in cases of left renal cancer, as surgeons typically focus on the hilar and para-aortic regions rather than the fat anterior to the psoas muscle below the kidney's lower pole when performing lymphadenectomy for staging or treatment purposes. Some studies have reported cases of metastasis to the psoas muscle or surrounding areas, but these are not the primary sites of lymphatic drainage for left kidney cancer 2, 3. In the context of lymph node metastasis, the presence of subdiaphragmatic lymph node metastases has been associated with poor prognosis in metastatic renal cell carcinoma patients treated with targeted therapies 1. However, the fat anterior to the psoas muscle below the lower pole of the left kidney is not a primary site of lymphatic drainage, and its involvement in metastasis would be considered secondary or distant metastasis. Therefore, the primary focus for lymph node dissection in left renal cancer should remain on the hilar and para-aortic regions, with the understanding that scattered lymph nodes in the retroperitoneal fat, including the area anterior to the psoas muscle, may be involved in advanced or metastatic disease.