Higher Risk Renal Angiomyolipomas: Surveillance Remains a Safe Management Option.

Introduction: This retrospective study furthers our understanding of risk factors associated with hemorrhage and intervention in renal angiomyolipomas (R-AMLs), particularly in larger tumors (≥4 cm) and in childbearing-age (CBA; younger than 50 years) women. The objective was to refine risk stratification and optimize patient management.

Methods: Review of our institutional database identified patients with radiographic R-AML from 1997 to 2023. Patient characteristics, R-AML characteristics, and clinical course were collected. Patients were grouped by management trajectories and analyzed across R-AML size, sex, and CBA woman status. Growth rates were modeled using linear mixed-effects regression.

Results: Of the 162 patients in this cohort, 22% had large R-AMLs (≥4 cm), of which the majority (66%) were managed with surveillance and a substantial portion (43%) never underwent intervention. The 23% of the cohort who were CBA women were similarly primarily managed with surveillance (74%), and more than half never underwent intervention (53%). The median follow-up on surveillance was 5.4 years. There was a significantly higher modeled growth rate with larger baseline tumor size, but growth rate was not affected by CBA woman status. Most cases of bleeding were in patients with markedly enlarged R-AMLs with multiple risk factors, but there were no serious adverse events.

Conclusions: This study is enriched for large R-AMLs and uniquely focuses on CBA women. It reinforces the notion that most large R-AMLs are treated asymptomatically and do not necessarily represent the bleeding risk historically ascribed to them. It suggests that CBA woman status alone should not motivate R-AML treatment.