The impact of renal angiomyolipoma on estimated glomerular filtration rate in patients with tuberous sclerosis complex

BACKGROUND: There is a growing concern that renal impairment may develop in patients with renal angiomyolipomas (AMLs) associated with tuberous sclerosis complex (TSC) as a consequence of the disease itself and/or the interventions to mitigate the risk of hemorrhage. OBJECTIVE: To assess the estimated glomerular filtration rate (eGFR) in patients with bilateral renal AMLs and the impact of tumor burden and intervention on renal function. DESIGN: Retrospective study. SETTING: Urology department of a tertiary care hospital. PATIENTS AND METHODS: All adult patients (≥18 years of age) with TSC-associated renal AMLs seen from October 1998 to June 2015. We included only patients with bilateral tumors or solitary kidneys at the last follow-up. MAIN OUTCOME MEASURES: The eGFR, renal volume, and number and type of interventions. RESULTS: We identified 12 patients (median age 27.6, interquartile range 23.7–39.9 years), a median follow-up period of 1266 days (33–3133), and a median renal size of 454.7 mL (interquartile range 344.7–1016.9 on the right side; 558.1 mL, interquartile range 253.7–1001.4 on the left). In 11 (91.7%) patients, the eGFR was >60 mL/min/1.77 m(2). Six patients had three total nephrectomies, one had a contralateral partial nephrectomy, and seven had selective arterial embolizations. Intervention was associated with a significantly reduced eGFR. The renal size did not correlate with the eGFR. CONCLUSIONS: TSC-associated renal AMLs may attain a large size but normal renal function is maintained in 92% of patients. Interventions to mitigate the risk of hemorrhage are associated with decreased renal function. LIMITATIONS: The renal size was used as a surrogate for tumor size. Other limitations were the limited number of patients and lack of split renal function testing.