Spontaneous Retroperitoneal Hemorrhage Causing Page Kidney as the Initial Presentation of Clear Cell Renal Cell Carcinoma

Spontaneous retroperitoneal hemorrhage is an uncommon presentation of renal pathology, and its association with Page kidney secondary to underlying renal cell carcinoma is exceedingly rare. We describe a 56-year-old man with no prior comorbidities who presented with acute abdominal pain, hemodynamic instability, and a significant hemoglobin drop. CT angiography revealed a massive left retroperitoneal hematoma measuring 16 × 12 × 32 cm, associated with Page kidney physiology, and a 7.7 × 8.6 × 8.7 cm exophytic complex hemorrhagic cystic lesion arising from the lower pole of the left kidney. Emergency super-selective angioembolization successfully controlled active bleeding. Serial imaging over subsequent weeks demonstrated hematoma regression and interval necrosis of the renal lesion without further contrast extravasation. Despite initial obscuration by hemorrhage, the lesion remained radiologically suspicious, prompting repeated multidisciplinary review. Functional studies showed preserved but reduced split renal function. Given persistent concern for malignancy, the patient underwent laparoscopic radical nephrectomy. Histopathology confirmed clear cell renal cell carcinoma with perinephric extension (pT3a) and no lymphovascular or nodal invasion. He was subsequently referred for adjuvant pembrolizumab therapy. This case underscores the importance of recognizing Page kidney in spontaneous renal hemorrhage, maintaining vigilance for occult malignancy, and adopting a staged multidisciplinary approach that prioritizes hemorrhage control while preserving oncologic decision-making.