METASTATIC PHEOCHROMOCYTOMA WITH A LONG-TERM RESPONSE AFTER I-131 METAIODOBENZYLGUANIDINE THERAPY

Iodine-131 metaiodobenzylguanidine ([I-131] MIBG), a radiopharmaceutic al agent, is used for treating malignant phaeochromocytoma. [I-131]MIB G therapy results in a hormone response rate of approximately 50%, but generally it yields only a partial or no tumour response, We present a case of a 46-year-old woman with a familial history of von Hippel-Li ndau disease, who was treated with [I-131]MIBG for a metastatic phaeoc hromocytoma involving the lungs, liver and bones, The patient received a cumulative dose of 33.3 GBq (900 mCi) and a complete hormone respon se was observed, as evaluated on the basis of catecholamine and metane phrine levels, Conventional radiography, computerized tomography and [ I-131]MIBG scintigraphy indicated that a near-complete tumour regressi on was achieved, with no evidence of relapse during a dr-year follow-u p period. This case thus demonstrates that treatment with [I-131]MIBG may lead to a dramatic tumour response in malignant phaeochromocytoma presenting both soft tissue and bone metastases.