Functioning Retroperitoneal Paraganglioma, Paracaval in Location: Complete Resection Without Vascular Graft Interposition. Case Report.

Retroperitoneal paragangliomas are rare neuroendocrine tumors derived from neural crest cells. When functional, they secrete catecholamines that cause severe hypertensive crises. Their location near the inferior vena cava increases the complexity of surgical treatment. We present the clinical case of a 60-year-old female patient with a history of partial nephrectomy for renal carcinoma and chronic diseases, such as diabetes and hypertension. She presented with recurrent episodes of palpitations, sustained tachycardia, diaphoresis, and anxiety. Imaging revealed a solid-cystic paracaval mass, in addition to the presence of plasma metanephrines, confirming its functionality. Complete resection was performed prior to pharmacological treatment with alpha- and beta-adrenergic blockers. Timely diagnosis, multidisciplinary evaluation, and adequate preoperative preparation allow for safe surgical resection without major complications.