嗜鉻細胞瘤為一罕見之腫瘤，約0.1%之高血壓病人可發現有此腫瘤。轉移性之惡性嗜鉻細胞瘤約佔全體嗜鉻細胞瘤之10-15%。惡性嗜鉻細胞瘤預後相當不良，其五年存活率僅約40%。儘管原發性之手術切除是首要之治療方式，在某些情況下，體外放射線治療仍不失為替代性之治療方法。本研究提出兩例惡性嗜鉻細胞瘤病患分別接受手術後放射治療或緩和性放射治療，並針對過去惡性嗜鉻細胞瘤病患接受放射治療之結果進行文獻回顧。

Pheochromocytomas are rare tumors that occur in approximately 0.1% of patients with hypertension. About 10-15% of pheochromocytomas presents with metastasis. Patients with malignant pheochromocytoma have a poor prognosis with an average 5-year survival of about 40%. Primary surgical resection is the treatment of choice whenever possible. External beam radiation may also be the alternative treatment modality for some situations. We reported two cases of malignant pheochromocytomas who received radiotherapy as postoperative adjuvant treatment and palliation. Relevant literatures are also reviewed.