後腹腔副神經瘤合併左側腎靜脈直接侵犯 - 病例報告

李懿文、陳彥達

高雄長庚紀念醫院泌尿科

 Retroperitoneal sympathetic paraganglioma with left renal vein direct invasion - Case Report

 I-Wen Lee, Yen-Ta Chen

Department of Urology, Chang Gung Memorial Hospital, Kaohsiung Medical Center,
Kaohsiung, Taiwan.

[Introduction]

Pheochromocytomas and paragangliomas are uncommon tumors that produce catecholamines, originating from paraganglia derived from neural crest cells. Pheochromocytomas develop from cells in the adrenal medulla, while paragangliomas form in paraganglia outside the adrenal glands. Most sympathetic paragangliomas are found in the abdomen (97%), with less frequent occurrences in the thorax and neck. These tumors, particularly when located outside the head and neck, are rare and often cause vague symptoms related to excessive catecholamine release, such as hypertension, headaches, and tachycardia. Imaging techniques like CT, MRI, and radionuclide scans (MIBG scintigraphy) are essential for locating these tumors. Although many paragangliomas are sporadic, up to 50% are associated with genetic mutations, including those in the SDH genes or linked to hereditary syndromes like multiple endocrine neoplasia (MEN2), neurofibromatosis type 1 (NF1), and von Hippel Lindau (VHL).

[Case history]

A 65-year-old Asian female with a history of primary hyperparathyroidism, who underwent a right lower parathyroidectomy in April 2024, was incidentally found to have a left suprarenal hypoechoic mass, 8x7 cm in size (Fig.1), during a routine renal ultrasound. The mass, lacking significant blood supply, was further evaluated with contrast-enhanced computed tomography (CT), which revealed a well-defined, heterogeneous left retroperitoneal mass with cystic components, measuring 8.3x8.1 cm. The mass was closely associated with the left renal hilum, duodenum, and pancreas (Fig.2,3). The patient was referred to the Urology Outpatient Department with a preliminary diagnosis of a left adrenal tumor or paraganglioma.

The patient reported no symptoms of hypertension, weight loss, headaches, sweating, palpitations, or family history of adrenal/retroperitoneal tumors or hereditary syndromes. Physical examination and urine analysis were unremarkable. Lab results showed a mild elevation in serum normetanephrine, while levels of metanephrine, aldosterone, and renin were within normal limits. Based on these findings, pheochromocytoma or paraganglioma was suspected. After informed consent was obtained, the patient underwent a left retroperitoneal tumor en-bloc resection via a midline transperitoneal approach. A general surgeon assisted in successfully separating the tumor from the duodenum and pancreas. However, the left renal vein was found to be severely engorged due to direct tumor invasion (Fig.4,5,6), necessitating a simultaneous left radical nephrectomy. The operation lasted 285 minutes, with a total blood loss of 300 mL, and no drainage tube was required post-hemostasis. The patient recovered well and was discharged on postoperative day 4 after Foley catheter removal.

The final pathology confirmed a sympathetic paraganglioma with direct invasion of the left renal vein, classified as AJCC 8th Pathological Stage III (pT3N0). The left kidney, ureter, adrenal gland, and renal sinus lymph nodes (0/1) were free of malignancy, and surgical margins were clear. Immunohistochemical studies supported the diagnosis of a sympathetic paraganglioma. The patient remains disease-free one-month post-surgery.

[Discussion and Conclusion]

Paragangliomas are rare neuroendocrine tumors derived from chromaffin cells and represent 10% of neuroendocrine tumors, primarily located along the sympathetic chain. Most commonly found in men aged 30-45, these tumors can be associated with familial syndromes such as multiple endocrine neoplasia, von Hippel-Lindau disease, and neurofibromatosis, often presenting bilaterally in inherited cases. The preferred surgical approach for resecting abdominal paragangliomas is endoscopic, including laparoscopic and retroperitoneal techniques, which reduce postoperative morbidity, hospital stays, and costs compared to open surgery. However, larger or invasive tumors, such as this case with renal vein invasion, may require open procedures. While 15-35% of paragangliomas are malignant, distinguishing benign from malignant forms is challenging due to the lack of reliable markers; metastasis indicates a poor prognosis, with a 5-year survival rate of 20-45%. Long-term follow-up is essential, including imaging and biochemical tests 3–4 months post-surgery. Regular biochemical monitoring is necessary for at least three years for catecholamine-secreting tumors, with lifelong testing recommended for both functional and nonfunctional tumors. We present a case of a retroperitoneal paraganglioma with direct invasion of the left renal vein that was completely excised. This case highlights the importance of considering extra-adrenal paragangliomas in the differential diagnosis of retroperitoneal masses, particularly those near the abdominal aorta.