Renal manifestations occur frequently in TSC. Rakowski et al
. reported renal lesions in 57.5% TSC patients; of these, AML was present in 85.4%, cysts in 44.8%, and renal cell carcinoma in 4.2%.[1
] TSC-associated AML is more likely to cause spontaneous hemorrhage compared with its sporadic counterpart, with a hemorrhagic risk of 25% to 50%.
TSC patients are also predisposed to nephrolithiasis because of both the disease and its treatments. For example, drugs like topiramate have proven to be effective for some forms of TSC-associated epilepsy; however, they also increase the risk of nephrolithiasis. Patients are also at higher risk for renal cystic disease because disruption of distal tubular function by a significant cyst burden leads to hypocitraturia. Our patient was not undergoing any treatment for epilepsy, and CT demonstrated no evidence of renal cystic lesions.
Traditional surgical treatment of renal calculi, including minimally invasive procedures like percutaneous nephrolithotomy (PNL) or extracorporeal shockwave lithotripsy (ESWL), may lead to bleeding in patients with renal AMLs. PNL remains a milestone technique with a high success rate and with a low percentage of major complications; however, the blood transfusion rate reported varies from 11.2% to 17.5%.[2
] PNL involves puncture and dilation of the renal collecting system via the renal parenchyma and poses an unacceptable risk of hemorrhage in kidneys with AML, although there are two reported cases of PNL performed directly through a renal AML.[3
] On the other hand, ESWL requires large numbers of shock waves, which can lead to capillary damage with parenchymal or subcapsular hemorrhage; ESWL-induced retroperitoneal bleeding has been reported in a patient with renal AML.[5
Recent studies have evaluated F-URS as an alternative treatment for patients with contraindications to PNL or ESWL, such as pregnant woman, obese patients, or those with coagulopathy. Indeed, F-URS using pulsed laser energy can fragment stones with less risk of hemorrhage. Furthermore, F-URS is a minimally invasive procedure that can treat <2-cm renal calculi with a low morbidity and high success rate. Our case and other reported cases indicate that F-URS can also safely treat larger stones.[6
] However, the management of lower pole renal calculi with F-URS remains debatable because of limited access and poor clearance of stone fragments.[7
] By the current literature, PNL should be considered the first line of treatment for greater than 2-cm lower pole renal calculi.[8
] Further advances in endoscopic technology and techniques are required to resolve the limitations of F-URS, including the technical difficulty in removing large stones, intrarenal influx with infected stones, and prolonged surgical duration.
In conclusion, retrograde F-URS with holmium laser lithotripsy is an effective, minimally invasive therapy for patients at high risk of renal hemorrhage.