From the Guidelines
The 3 mm nodule in the fat anterior to the psoas muscle is likely a benign post-surgical change rather than a recurrence of renal cell carcinoma, and continued routine surveillance is appropriate rather than more aggressive intervention. This nodule was not present before the partial nephrectomy but appeared after surgery and has remained stable at 3 mm over three years of surveillance. The stability of this finding, along with the fact that the original chromophobe RCC was small (1.3 cm) and low stage (T1A) with favorable pathologic features, supports a low risk of recurrence 1.
According to the most recent guidelines, for low-risk/T1 tumors, chest imaging is recommended every 12 to 24 months for 3 to 5 years, and abdominal imaging can be performed yearly for 3 to 5 years 1. The fact that this nodule has not grown in size over three years is reassuring, and the term "matured" used by the radiologist suggests it has developed a more defined appearance over time, which is consistent with a benign post-surgical change.
The American College of Radiology and other major international urological and oncological societies recommend imaging surveillance of the chest and abdomen after primary treatment for RCC, but the guidelines vary in the recommended imaging modalities and timelines 1. However, given the low risk of recurrence in this patient, a more conservative approach with continued routine surveillance is justified.
It is also important to note that the growth rate of renal tumors is low in most cases, with a mean growth rate of 3 mm/year, and progression to metastatic disease is reported in 1%-2% of patients 1. Therefore, continued routine surveillance rather than more aggressive intervention is the most appropriate course of action, taking into account the patient's low risk of recurrence and the potential risks and benefits of further treatment 1.
From the Research
Significance of a 3mm Nodule
The significance of a 3mm nodule in the fat anterior to the psoas muscle, which appeared after partial nephrectomy for a 1.3cm chromophobe renal cell carcinoma (RCC) and has remained stable over three years, can be considered in the context of soft tissue tumor evaluation.
- The nodule's small size and stability over time are important factors in assessing its potential significance.
- According to 2, MRI is the most important and sensitive imaging modality in the differentiation of unclear soft tissue tumors, and a systematic approach can help narrow down the differential diagnoses.
- However, the provided studies do not specifically address the significance of a small, stable nodule in this context.
Evaluation of Soft Tissue Masses
In general, the evaluation of soft tissue masses involves a systematic approach to determine whether the mass is benign or malignant.
- As noted in 3, most soft-tissue tumors have characteristic signal characteristics on MRI, but some masses may be indeterminate and require biopsy for diagnosis.
- 4 emphasizes the importance of a systematic approach to the evaluation and management of soft tissue masses, given the overlap in presentation between benign and malignant tumors.
- The decision to perform a biopsy or other diagnostic tests depends on the specific characteristics of the mass and the patient's clinical history.
Surveillance and Monitoring
The use of surveillance imaging to monitor for potential recurrence or new tumors is a topic of ongoing debate.
- 5 discusses the controversy surrounding the use of surveillance scans in lymphoma patients, highlighting concerns about radiation-associated health risks and the potential psychological impact on patients.
- In contrast, 6 reviews the evidence for surveillance imaging in breast cancer survivors, emphasizing the importance of balancing benefits and harms in this population.
- However, these studies do not directly address the significance of a small, stable nodule in the context of a patient with a history of RCC.