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

Abstract

BACKGROUNDThere 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.OBJECTIVETo assess the estimated glomerular filtration rate (eGFR) in patients with bilateral renal AMLs and the impact of tumor burden and intervention on renal function.DESIGNRetrospective study.SETTINGUrology department of a tertiary care hospital.PATIENTS AND METHODSAll 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 MEASURESThe eGFR, renal volume, and number and type of interventions.RESULTSWe 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 m2. 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.CONCLUSIONSTSC-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.LIMITATIONSThe 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.

Renal Manifestations of Tuberous Sclerosis Complex: Key Findings From the Final Analysis of the TOSCA Study Focussing Mainly on Renal Angiomyolipomas

“…In our study, the prevalence of angiomyolipoma was significantly higher in those with TSC2 mutations. This was in line with the previous other reports (7,8,17,23). We also observed that patients with TSC2 mutations had angiomyolipoma at early age and experienced higher rates of bleeding complications (haematuria and hemorrhage).…”

“…In our previous publication from the TOSCA core section interim analysis ( 13 ), we reported that the occurrence rate of renal angiomyolipomas was lower in the TOSCA cohort compared to other published literature ( 8 , 9 ). Rates of haematuria and hypertension were also lower compared with those reported in TSC patients in other studies ( 6 , 7 , 21 , 22 ), this may be a reflection of the age relatively young age of our subjects and possibly under-ascertainment. These lower rates of occurrence of renal angiomyolipomas and angiomyolipoma-related complications could be explained by a different (younger) age range of our population; however the current analysis shows that angiomyolipoma prevalence rose progressively with age, to 77.7% in those over 40 years of age, whereas complication rates remained much lower than in other studies.…”

“…Renal manifestations are one of the most common causes of morbidity and were historically reported as the primary cause of death in adult TSC patients ( 3 – 5 ). The relative importance of mechanisms postulated to lead to impaired renal function are unknown ( 6 ) but a major risk factor may be intervention for renal angiomyolipomas ( 7 ).…”

Renal angiomyolipoma presenting as acute abdomen in a previously undiagnosed patient of tuberous sclerosis

“…Because AML has a highly vascular tissue, repeated embolisation procedures may lead to rapid kidney function decline through ischaemic acute tubular necrosis. 3 Acute kidney injury (AKI) post embolisation can be due to contrast related AKI, vascular compromise of nephrons due to coiling of vessels, inflammation caused due to embolisation agents, formation of haematoma, perioperative haemodynamic instability and atheroembolic phenomenon.…”

The Risks of Renal Angiomyolipoma: Reviewing the Evidence

“…Some reports indicated that intervention was not associated with renal impairment, while others showed that inter vention/surgery rather than the AML lesions was associated with deterioration of renal function ( 119 , 120 ). The discrepancy may be related to the relative proportions of sporadic versus TSC-RAML, where most of the reports associating renal impairment with RAML involve TSC patients.…”