Does Size Predict Aggressiveness?: Exploring Sporadic Multifocal Tumors in a 10-Year Retrospective Analysis

Area of Science:

• Urologic Oncology
• Nephrology
• Surgical Pathology

Background:

• Localized kidney tumors' malignant potential is typically predicted by size and growth.
• Treatment for multifocal renal masses often prioritizes the largest or index tumor.
• The aggressiveness of sporadic multifocal renal tumors requires further investigation.

Purpose of the Study:

• To examine the histologic concordance of sporadic multifocal renal tumors.
• To determine if tumor size is the primary determinant of aggressiveness in multifocal renal tumors.

Main Methods:

• Retrospective chart review of 128 patients with sporadic multifocal renal tumors undergoing nephrectomy.
• Analysis of surgical pathology parameters including tumor size, TNM grading, and staging.
• Exclusion of patients with syndromic diseases.

Main Results:

• 64% of multifocal renal tumors exhibited concordant histology; 36% were discordant.
• The index tumor showed more aggressive histology in 77.3% of patients.
• 16% of patients with a benign index tumor had a malignant secondary tumor.

Conclusions:

• Multifocal renal tumors frequently present with discordant histology.
• Tumor size is not always the greatest determinant of aggressiveness.
• Managing sporadic multifocal renal cell carcinoma (RCC) requires considering nonindex lesions due to potential for more aggressive disease.