What is the clinical significance of a benign soft tissue mass and a stable 3 mm nodule in the fat anterior to the psoas muscle in a patient with a history of partial nephrectomy for chromophobe renal cell carcinoma?

From the Guidelines

The clinical significance of a benign soft tissue mass and a stable 3 mm nodule in the fat anterior to the psoas muscle in a patient with a history of partial nephrectomy for chromophobe renal cell carcinoma is minimal, and no intervention is needed at this time. The patient's history of partial nephrectomy for chromophobe renal cell carcinoma and the presence of a benign soft tissue mass and a stable 3 mm nodule are being evaluated in the context of potential recurrence or metastasis. According to the American Society of Clinical Oncology clinical practice guideline 1, small renal masses (SRMs) are often incidentally detected and may be benign or have limited metastatic potential. The guideline also notes that certain renal tumor histologies have distinct imaging characteristics, but current radiologic imaging cannot reliably discriminate.

Given the stability of the 3 mm nodule over time and its small size, it is likely a post-surgical change rather than a metastasis. The European Society for Medical Oncology (ESMO) clinical practice guideline for diagnosis, treatment, and follow-up of renal cell carcinoma 1 recommends partial nephrectomy as the preferred option for T1 tumors and suggests that active surveillance is an option for those with a short life expectancy and for patients with small renal masses. The guideline also notes that the growth rate of renal tumors is low in most cases, and progression to metastatic disease is reported in 1%-2% of patients.

In this case, the patient's excellent prognosis for T1A chromophobe RCC (over 95% 5-year survival) and the absence of adverse features like sarcomatoid differentiation or necrosis in the original tumor further support that these findings represent benign post-surgical changes rather than recurrence or metastasis.

• Key points to consider:
  • The patient's history of partial nephrectomy for chromophobe renal cell carcinoma
  • The presence of a benign soft tissue mass and a stable 3 mm nodule
  • The stability of the 3 mm nodule over time and its small size
  • The excellent prognosis for T1A chromophobe RCC
  • The absence of adverse features like sarcomatoid differentiation or necrosis in the original tumor Continued routine surveillance is recommended following the standard protocol for T1A RCC, which typically involves imaging every 12 months for at least 5 years.

From the Research

Clinical Significance of Benign Soft Tissue Mass and Stable 3 mm Nodule

• The clinical significance of a benign soft tissue mass and a stable 3 mm nodule in the fat anterior to the psoas muscle in a patient with a history of partial nephrectomy for chromophobe renal cell carcinoma is not directly addressed in the provided studies.
• However, studies have shown that solid renal masses, which can be benign or malignant, are often incidentally detected at imaging as small localized lesions 2.
• The ability of imaging to differentiate between benign and malignant lesions is limited, and surgical resection is often performed due to the uncertainty of the diagnosis 2.
• In the case of angiomyolipomas, which are a type of benign renal tumor, imaging features such as high attenuation on unenhanced CT sequences and homogeneous enhancement on CT can be suggestive of a benign lesion 3.
• However, the presence of a stable 3 mm nodule in the fat anterior to the psoas muscle is not specifically addressed in the provided studies, and its clinical significance is unclear.

Surveillance and Management

• Surveillance imaging strategies are important in the management of various types of tumors, including pituitary adenomas 4 and lung adenocarcinomas 5.
• The optimal strategy for surveillance imaging is not clearly established and should be individualized based on clinical presentation, history, and tumor characteristics 4.
• Active surveillance has emerged as an alternative to operative management for low-risk tumors, such as papillary thyroid microcarcinoma 6.
• However, the provided studies do not specifically address the surveillance and management of a benign soft tissue mass and a stable 3 mm nodule in the fat anterior to the psoas muscle in a patient with a history of partial nephrectomy for chromophobe renal cell carcinoma.