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 (RCC)?

From the Guidelines

The presence 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 (RCC) does not appear to be concerning for cancer recurrence, and therefore, does not warrant additional intervention at this time. The patient's history of partial nephrectomy for chromophobe RCC is relevant, as the risk of recurrence is a concern in these patients 1. However, the findings of a benign soft tissue mass and a stable 3 mm nodule in the fat anterior to the psoas muscle are likely post-surgical changes rather than metastases. The American College of Radiology guidelines for post-treatment follow-up and active surveillance of clinically localized renal cell carcinoma recommend imaging surveillance of the chest and abdomen after primary treatment for RCC 1. For low-risk/T1 tumors, chest imaging is recommended every 12 to 24 months for 3 to 5 years, and abdominal imaging is recommended yearly for 3 to 5 years 1. Given the small size of the original tumor and its favorable histology, the negative biopsy of the larger mass, and the stable nature of the small nodule since surgery, these findings most likely represent benign post-surgical changes rather than recurrent disease 1. Key points to consider in this patient's case include:

• The patient's history of partial nephrectomy for chromophobe RCC
• The presence of a benign soft tissue mass and a stable 3 mm nodule in the fat anterior to the psoas muscle
• The lack of concerning features for cancer recurrence
• The recommendation for continued surveillance according to standard protocols for T1A RCC
• The use of CT abdomen as a sensitive method for detecting recurrences in the treatment bed and other common sites of metastases in the abdomen 1. Overall, the patient's findings do not warrant additional intervention at this time, and continued surveillance according to standard protocols for T1A RCC is appropriate.

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 (RCC) is not directly discussed in the provided studies 2, 3, 4, 5, 6.
• The studies primarily focus on the diagnosis and characterization of nodules in different organs, such as the liver 2, 6, thyroid 3, and lungs 4, 5.
• However, the studies do provide information on the importance of imaging modalities, such as CT and MRI, in detecting and characterizing nodules 2, 3, 4, 5, 6.
• The studies also highlight the role of biopsy in providing an accurate diagnosis when imaging findings are inconclusive or discordant 6.

Imaging Modalities and Nodule Characterization

• The studies discuss the use of various imaging modalities, including CT, MRI, and ultrasonography, in detecting and characterizing nodules 2, 3, 4, 5, 6.
• The importance of contrast-enhanced imaging in detecting arterial hypervascularity and washout, which are considered classical imaging features of hepatocellular carcinoma (HCC), is highlighted in 2 and 6.
• The use of non-enhanced MRI sequences, such as T2-STIR and T2, in characterizing pulmonary nodules is discussed in 5.

Role of Biopsy

• The study 6 emphasizes the role of biopsy in providing an accurate diagnosis when imaging findings are inconclusive or discordant.
• The study found that biopsy provided an initial accurate diagnosis in patients with discordant imaging findings between CT and MRI 6.