What is the significance of a 3 mm nodule near the left kidney in a patient with a history of partial nephrectomy for Chromophobe renal cell carcinoma (RCC)?

From the Guidelines

The 3 mm nodule near the left kidney in a patient with a history of partial nephrectomy for Chromophobe renal cell carcinoma (RCC) is likely a benign finding that does not require immediate intervention, and active surveillance with serial imaging is recommended. Given the patient's history of partial nephrectomy for Chromophobe RCC, the presence of a 3 mm nodule near the left kidney is a finding that warrants careful consideration. According to the European Association of Urology guidelines on renal cell carcinoma, active surveillance is a viable option for patients with small renal masses, especially in elderly and comorbid patients who have a low RCC-specific mortality and significant competing-cause mortality 1.

The guidelines recommend serial abdominal imaging (US, CT, or MRI) with delayed intervention reserved for those who show clinical progression during follow-up, and a renal biopsy is recommended before surveillance 1. The growth rate of small renal masses is typically slow, with a mean growth rate of 3 mm/yr, and progression to metastatic RCC is rare (1-2%) 1.

In the context of this patient's history and the current guidelines, active surveillance with serial imaging at 3 and 6 months, then every 6 months up to 3 years, and annually thereafter, is a reasonable approach. This approach allows for monitoring of the nodule's size and growth rate while minimizing the risks associated with unnecessary interventions. If the patient experiences any new symptoms such as flank pain, blood in urine, or unexplained weight loss, they should contact their urologist promptly for evaluation.

It is essential to note that the patient's original cancer was a small (likely less than 4 cm, although exact size not specified) chromophobe RCC without aggressive features, which generally has an excellent prognosis with low recurrence rates after complete surgical removal, especially for small, early-stage tumors 1. However, continued monitoring is crucial to ensure the nodule remains stable and to detect any potential changes that may indicate cancer recurrence.

Key points to consider in the management of this patient include:

• The patient's history of partial nephrectomy for Chromophobe RCC
• The presence of a 3 mm nodule near the left kidney
• The recommendation for active surveillance with serial imaging
• The importance of monitoring for new symptoms and potential changes in the nodule's size or growth rate
• The excellent prognosis associated with small, early-stage chromophobe RCC tumors after complete surgical removal.

From the Research

Clinical Significance of a 3 mm Nodule near the Left Kidney

The presence of a 3 mm nodule near the left kidney in a patient with a history of partial nephrectomy for Chromophobe renal cell carcinoma (RCC) warrants careful consideration.

• The nodule's small size and location near the left kidney may indicate a potential recurrence or metastasis of the original tumor 2.
• Chromophobe RCC is generally considered to have a favorable prognosis, but it can still exhibit aggressive behavior, particularly if it shows retrograde venous invasion or gain of chromosome 21 2.
• The diagnosis of Chromophobe RCC is typically established based on histological examination, which may reveal characteristic features such as a well-defined homogeneous mass and hypo-vascular soft tissue enhancement 3.
• In some cases, Chromophobe RCC may present as a cystic renal mass with mural nodules, which can make diagnosis more challenging 3.

Diagnostic Considerations

• The differential diagnosis for a cystic renal mass includes benign entities such as oncocytoma, as well as malignant neoplasms like clear cell RCC and Chromophobe RCC 3.
• Histological examination and immunohistochemical staining can help distinguish between these entities, with Chromophobe RCC typically expressing diffuse and uniform CK7 and positive CD117 expression 4.
• Genetic profiling may also be useful in diagnosing and predicting the behavior of Chromophobe RCC, with multiple losses of chromosomes 1,2,6,10,13,17, and 21 considered to be genetic hallmarks of this tumor subtype 4.

Management and Prognosis

• The management of a patient with a history of Chromophobe RCC and a new 3 mm nodule near the left kidney will depend on various factors, including the nodule's characteristics, the patient's overall health, and the presence of any metastatic disease 2.
• In general, Chromophobe RCC is considered to have a favorable prognosis, but the presence of aggressive features such as retrograde venous invasion or gain of chromosome 21 may indicate a poorer outcome 2.
• Close monitoring and regular follow-up imaging may be necessary to detect any changes in the nodule's size or characteristics, and to guide further management decisions 5, 3, 6.