[Radiologic findings in renal metastases]

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Renal metastases are secondary malignant tumors in the kidney.
• Distinguishing the primary source of renal metastases is crucial for patient management.
• Ultrasound (US) and Computed Tomography (CT) are common imaging modalities for evaluating renal lesions.

Purpose of the Study:

• To retrospectively analyze and compare the US and CT findings of renal metastases.
• To identify characteristic imaging features differentiating renal metastases from different primary malignancies, specifically lymphoma and pulmonary carcinoma.
• To assess the sensitivity and accuracy of US compared to CT in detecting renal metastases.

Main Methods:

• Retrospective analysis of 41 cases with known primary malignancies (lymphoma, pulmonary carcinoma) and renal metastases.
• Review of US findings in all 41 cases and CT findings in 22 cases.
• Categorization of renal metastases based on laterality, multiplicity, echogenicity, and echo structure (US), and density and enhancement patterns (CT).

Main Results:

• Renal metastases were frequently bilateral (20/41) and multiple (21/41).
• Lymphoma metastases typically appeared infiltrative, homogeneous, and echo-poor on US.
• Pulmonary carcinoma metastases were often non-infiltrative, non-homogeneous, echo-poor, and sometimes hyperechoic on US.
• CT identified smaller and more numerous lesions than US, with one false-negative US finding and four cases where US detected only a subset of CT-identified lesions.
• Hyperechoic metastases were not observed in lymphoma cases.

Conclusions:

• US and CT exhibit distinct patterns for renal metastases from lymphoma and pulmonary carcinoma.
• CT demonstrates superior sensitivity in detecting smaller and more numerous renal metastatic lesions compared to US.
• Imaging characteristics can aid in differentiating the primary origin of renal metastases, guiding further clinical decisions.