Etiology and clinical guidelines for the diagnosis and treatment of pheochromocytoma in Japan

: Although pheochromocytoma is one curable cause of endocrine hypertension, approximately 10% of patients have malignant disease. Since the histopathologic diagnosis of malignancy at the time of first surgery is difficult and malignancy is confirmed only after the detection of metastasis, it is a representative intractable rare disease without effective treatment. A nationwide survey in Japan in 2009 found 2,600 cases of benign pheochromocytoma and 320 of malignant pheochromocytoma. There was no gender bias among patients, and the average age of onset was 40 to 45 years. Sixty-five percent were symptomatic including hypertension, but 35% were asymptomatic and found occasionally as incidentaloma Extraadrenal, bilateral, malignant, and familial cases each represented 10% of the total. A task force of the Ministry of Health, Labour and Welfare of Japan established the diagnostic criteria and clinical guidelines for pheochromocytoma/paraganglioma and malignant pheochromocytoma/paraganglioma. Typical cases of pheochromocytoma are readily diagnosed based on high catecholamine levels and imaging of tumor localization and can be cured by surgical resection of the tumor. In contrast, since no effective treatment for malignant pheochromocytoma has been established, a combination of various treatments including the administration of a-blockers, 131-MIBG irradiation, and cisplatin/vinblastine/dacarbazine chemotherapy, and radiation of bone metastases is recommended. Careful long-term follow-up is essential even in patients with benign pheochromocytoma.