What is the significance of a stable, 3mm nodular lesion in the fat anterior to the psoas, caudal to the lower pole of the left kidney, first identified 1.5 months after partial nephrectomy for a 1.3 cm low-grade Chromophobe Renal Cell Carcinoma (RCC), which has not demonstrated apparent growth over 3 years?

From the Guidelines

The 3mm nodule located in the fat anterior to the psoas and caudal to the lower pole of the left kidney is most likely benign and represents either post-surgical changes or a benign lymph node rather than recurrent or metastatic disease, given its stability over a 3-year period. This assessment is based on the fact that the nodule has not demonstrated apparent growth over 3 years, which is a key factor in differentiating benign from malignant lesions, as malignant lesions typically show progressive enlargement over time 1. The patient's original cancer was also favorable, being a small, low-grade chromophobe renal cell carcinoma, which further supports a low risk of recurrence or metastasis.

Key Considerations

• The nodule's stability in size over 3 years is a strong indicator of its benign nature.
• The lack of growth is reassuring, as malignant lesions typically demonstrate progressive enlargement.
• The patient's original cancer was favorable, with a small size and low grade, which supports a low risk of recurrence or metastasis.
• Continued surveillance with regular imaging, typically annual CT scans, is still recommended to monitor both the surgical site and this stable nodule, as per guidelines for post-treatment follow-up and active surveillance of clinically localized renal cell carcinoma 1.

Surveillance Recommendations

• Annual CT scans of the abdomen are recommended for at least 5 years after treatment for clinically localized renal cell carcinoma, as outlined in guidelines for follow-up and surveillance 1.
• The use of CT scans with and without IV contrast is preferred, unless contraindicated, to assess for recurrence or metastasis.
• Patients with a history of renal cell carcinoma should also undergo regular assessment for pulmonary metastases, typically with annual chest X-rays for 5 years, especially if they have low-risk RCC or oncocytic features 1.

Clinical Implications

• The management of this patient should follow the guidelines for post-treatment follow-up and active surveillance, with a focus on monitoring for recurrence or metastasis while minimizing unnecessary interventions.
• The stable nature of the nodule and the patient's favorable original cancer profile support a conservative approach, with continued surveillance rather than immediate intervention.
• Any changes in the nodule's size or appearance on future imaging should be carefully evaluated, and further investigation, such as biopsy, should be considered if there is suspicion of recurrence or metastasis 1.

From the Research

Significance of a Stable Nodular Lesion

The significance of a stable, 3mm nodular lesion in the fat anterior to the psoas, caudal to the lower pole of the left kidney, first identified 1.5 months after partial nephrectomy for a 1.3 cm low-grade Chromophobe Renal Cell Carcinoma (RCC), which has not demonstrated apparent growth over 3 years, is uncertain based on the provided studies.

• The studies provided do not directly address the significance of a stable nodular lesion in this specific location and context 2, 3, 4, 5, 6.
• However, studies on lung nodules suggest that small nodules (<3mm) may not always be indicative of benignity, and further evaluation may be necessary to determine their nature 3, 4, 5.
• In the context of liver nodules, any nodule in a cirrhotic liver should be considered as hepatocellular carcinoma until otherwise proved, but this may not be directly applicable to a nodular lesion in the fat anterior to the psoas 6.
• The management of probably benign nodular lesions should not only be guided by imaging classification, but also by clinical and anamnestic data, and a multidisciplinary approach may be necessary to select cases that require histologic verification instead of follow-up 2.

Clinical Implications

• The presence of a stable nodular lesion in the fat anterior to the psoas, caudal to the lower pole of the left kidney, may require further evaluation to determine its nature and significance.
• Clinical decision making should be guided by a combination of imaging findings, clinical data, and anamnestic information, rather than relying solely on imaging classification 2, 4.
• A multidisciplinary approach may be necessary to determine the best course of action for managing the nodular lesion, including the possibility of histologic verification or continued follow-up 2, 4, 5.