Background <p>Paraganglioma (PGL) are rare neuroendocrine tumors arising from extra-adrenal paraganglia. Renal hilar PGLs are exceptionally uncommon in children, and acute renal hypoperfusion with apparent renal atrophy due to extrinsic vascular compression has rarely been reported.</p> Case presentation <p>We report a child presenting with episodic hypertension, headache, dizziness, vomiting, and diaphoresis. Serial imaging demonstrated a small renal hilar mass associated with rapidly progressive renal hypoperfusion and acute reduction in left renal size. Renal angiography revealed focal compression of the left renal artery. Biochemical evaluation showed elevated catecholamines with activation of the renin–angiotensin–aldosterone system. Laparoscopic kidney-preserving tumor resection was performed, and histopathology confirmed a sympathetic PGL. Postoperatively, blood pressure normalized, and 6-month follow-up CT demonstrated restoration of left renal perfusion with marked recovery of renal size after complete tumor resection.</p> Conclusions <p>Acute renal hypoperfusion and apparent renal atrophy caused by extrinsic vascular compression may be reversible. Early recognition of renovascular compromise and timely kidney-preserving surgical intervention may prevent irreversible nephron loss in children. Genetic counseling, germline mutation screening, and long-term surveillance should also be considered in postoperative management.</p>