Everolimus improved renal function without reducing the size of a kidney angiomyolipoma in a patient with tuberous sclerosis complex: a case report

Background Tuberous sclerosis complex is an autosomal dominant genetic disorder that affects multiple organ systems and can result in tumors in the brain, skin, heart, and kidneys; it may also cause neurological symptoms. About 1 to 7% of patients develop end-stage renal disease due to bilateral renal angiomyolipoma. We herein describe a patient with a bilateral large kidney angiomyolipoma whose residual renal function was temporarily improved with everolimus treatment. Case presentation A 39-year-old man was diagnosed with tuberous sclerosis complex associated with an angiomyolipoma that was first detected at 12 years of age and had enlarged to a size that completely filled the bilateral kidneys. Although his kidney function was poor at the start of everolimus treatment as indicated by a creatinine-based estimated glomerular filtration rate of 13.7 mL/min/1.73 m2, his kidney function recovered with an annual increase in the glomerular filtration rate of 4.57 mL/min/1.73 m2 without morphological changes or a reduction in the size of the angiomyolipoma after everolimus treatment. As a result, we were able to delay the initiation of renal replacement therapy for more than 1 year. Conclusions Even in patients with tuberous sclerosis complex who exhibit decreased renal function, everolimus treatment can retain the renal function and delay introduction of dialysis without a reduction in the size of the renal angiomyolipoma. The pathophysiological mechanisms for the deterioration of renal function in patients with tuberous sclerosis complex may not involve renal parenchymal loss secondary to angiomyolipoma growth only but may also involve other mechanisms including glomerular hypertrophy and hyperfiltration associated with mTOR complex 1 overactivity.