Rare presentation of intraparenchymal renal artery aneurysm disguised as renal cell carcinoma: a case report and literature review.

Renal artery aneurysms (RAAs) are rare vascular abnormalities that are often detected incidentally, as most patients are asymptomatic and the lesions are discovered during imaging for unrelated conditions. Differentiating intraparenchymal RAAs (IPRAAs) from renal tumors using non-invasive imaging techniques remains challenging. Misdiagnosis as a renal malignancy, such as renal cell carcinoma (RCC), poses a significant risk of catastrophic hemorrhage if inadvertently subjected to biopsy or surgical procedures. We reported the case of a 75-year-old female with an IPRAA that mimicked RCC on contrast-enhanced computed tomography (CECT). However, a suspicious feeding artery to the renal mass was identified on computed tomography angiography (CTA) images. Further evaluation with positron emission tomography/magnetic resonance imaging (PET/MR) suggests the diagnosis of IPRAA. This was confirmed by digital subtraction angiography (DSA), and the aneurysm was successfully treated with transcatheter embolization. This case highlights the importance of including IPRAA in the differential diagnosis of renal masses and emphasizes the need for careful imaging evaluation to avoid potentially life-threatening complications from misdiagnosis.