Large calcified renal artery aneurysm in the renal sinus misdiagnosed as an intrapelvic calculus followed by mistakenly performed PCNL: a case report.

Background: Renal artery aneurysms (RAAs) are rare and usually asymptomatic, and some RAAs can be associated with calcifications, which may lead to misdiagnoses as renal calculi, which are then mistakenly treated.

Case Presentation: A 69-year-old female patient was admitted to the hospital with no discomfort and was diagnosed with a large right renal calculus. The ultrasound and computed tomography urography (CTU) scan suggested a large calculus in the right pelvis with hydrops of the kidney. Therefore, we chose percutaneous nephrolithotomy (PCNL) to treat the right renal calculus, but no calculi were found in the renal pelvis. When we removed the mucosa of the renal pelvis with a holmium laser, we observed a fluctuating unruptured aneurysm with calcification. Therefore, the previous diagnosis of a renal calculus was disregarded. The operation was stopped immediately, and then computed tomography (CT) angiography was performed, confirming the right renal aneurysm with calcification. Then, Renal artery aneurysm (RAA) coil embolization was performed. After a long-term follow-up, the patient recovered well.

Conclusions: The RAA of this patient had calcific changes, which led us to errors in the diagnosis. Hence, it is very important for surgeons to effectively distinguish between renal calculi and aneurysms with ring-like calcifications. Our case report looks back at the thrilling situation during the operation and advises surgeons on how to deal with this situation properly.