Renal lymphangiectasia, a rare entity of the renal lymphatic system affecting both genders and all ages, can manifest bilaterally or unilaterally and has been referred to by various terms, such as renal lymphangiomatosis, renal lymphangioma, and others. Distinguishing this condition from common pathologies, such as polycystic kidney disease or hydronephrosis, is crucial. This article presents an innovative clinical case of unilateral renal lymphangiectasia in a 67-year-old woman with a relevant medical history. Detection was achieved by ultrasound in primary care using the point-of-care ultrasound (POCUS) technique under the focused assessment with sonography in trauma (FAST) protocol, revealing findings suggestive of renal lymphangiomatosis. This case highlights the utility of advanced technologies, such as bedside ultrasound, in addressing and transforming the approach to rare medical conditions, offering a compelling reminder of the positive influence of technological innovation in clinical practice.