From the Guidelines
The 3 mm nodule found anterior to the psoas muscle below the left kidney is likely benign and represents either a small lymph node or residual post-surgical change rather than recurrent cancer. Given its small size, stability since the post-operative period, and the favorable characteristics of the original chromophobe renal cell carcinoma (small size, no sarcomatoid features, no necrosis, stage T1a), this finding does not warrant immediate intervention. Continued surveillance with regular imaging according to the urologist's follow-up protocol is recommended, as suggested by the American College of Radiology guidelines 1.
Key Considerations
- The patient's original tumor was a 1.3 cm exophytic Chromophobe renal cell carcinoma, which generally has an excellent prognosis with low recurrence rates after complete resection of a T1a tumor 1.
- The nodule's small size and stability since the post-operative period suggest it is related to post-surgical healing rather than cancer recurrence.
- The American College of Radiology guidelines recommend imaging surveillance of the chest and abdomen after primary treatment for RCC, with the frequency and modality of imaging depending on the patient's risk factors and tumor characteristics 1.
Recommended Course of Action
- Maintain scheduled follow-up appointments and imaging studies as directed by the urologist to track any potential changes in the nodule over time.
- Follow the recommended imaging surveillance protocol for low-risk/T1 tumors, which includes chest imaging every 12 to 24 months for 3 to 5 years and abdominal imaging yearly for 3 to 5 years 1.
- Consider the use of CT or MRI of the abdomen for surveillance, as these modalities are more frequently used than ultrasound for abdominal imaging in this context 1.
From the Research
Significance of a 3 mm Nodule
- The presence of a 3 mm nodule found in the fat anterior to the psoas muscle, below the lower pole of the left kidney, on imaging 3 years after a partial nephrectomy for a 1.3 cm exophytic Chromophobe renal cell carcinoma (RCC) is a significant finding that requires further evaluation 2, 3, 4, 5, 6.
- Chromophobe RCC is a distinct subtype of renal cell carcinoma with characteristic light microscopic, histochemical, and ultrastructural features, typically having a favorable clinical course 2.
- The nodule's location and size suggest the possibility of a local recurrence or a new primary tumor, which is a concern in patients with a history of RCC 3, 5.
Clinical Implications
- The patient's history of partial nephrectomy for Chromophobe RCC increases the risk of local recurrence or development of a new primary tumor 3, 5.
- Regular imaging follow-up is essential for early detection of potential recurrences or new tumors, as seen in this case 3, 5.
- The nodule's small size (3 mm) may indicate an early stage of disease, and prompt evaluation and management are crucial to prevent progression 5.
Diagnostic Considerations
- The differential diagnosis for the nodule includes local recurrence of Chromophobe RCC, new primary tumor, or other benign or malignant lesions 4, 6.
- Further imaging studies, such as MRI or CT scans, and possibly a biopsy may be necessary to determine the nature of the nodule 3, 5.
- The patient's clinical history, imaging findings, and biopsy results (if obtained) will guide the management of the nodule 2, 3, 4, 5, 6.