Antopol-Goldman (AG) lesion is a benign condition characterized by flank pain, hematuria, and radiologically detected filling defect in the renal pelvis. It is clinically important because it is confused with renal parenchymal and collecting system tumors. In this case report, we present a 75-year-old male patient who was evaluated with the suspicion of renal pelvis tumor but was diagnosed with AG lesion and treated conservatively after excluding malignancy with radiology, endoscopy, and pathology. Our aim is to emphasize the importance of diagnostic flexible ureterorenoscopy before planning radical treatment in patients with hematuria, flank pain, and radiological signs of filling defect in the renal pelvis.