Does iodine-131 meta-iodobenzylguanidine (MIBG) scintigraphy have an impact on the management of sporadic and familial phaeochromocytoma?

OBJECTIVES

To assess the impact of [(131)I]meta-iodobenzylguanidine ((131)MIBG) scintigraphy on the management of phaeochromocytoma.

DESIGN AND PATIENTS

Between 1982 and 2002, 83 patients with histologically proven phaeochromocytoma or paraganglioma were investigated using (131)MIBG scintigraphy. Seventeen of these patients, with a hereditary form of the disease, presented with 23 phaeochromocytomas [three neurofibromatosis type 1 (NF1), five von Hippel-Lindau disease (VHL), eight multiple endocrine neoplasia type 2A (MEN2A) and one type 2B (MEN2B)].

RESULTS

MIBG uptake was observed in 44/54 sporadic phaeochromocytomas (sensitivity 81.5%), 14/23 familial phaeochromocytomas (60.9%), 3/6 paragangliomas and 4/6 malignant phaeochromocytomas. No significant correlations were found between the degree of tracer uptake, tumour size and urinary metanephrine levels. No patients undergoing surgery for sporadic phaeochromocytoma had a second tumour located. Nine of 54 sporadic phaeochromocytomas had normal or mildly elevated urinary metanephrine levels (< 1.5 greater than normal). In eight of these patients, (131)MIBG was positive and confirmed the diagnosis of phaeochromocytoma. In malignant phaeochromocytomas (n = 6), MIBG demonstrated additional lesions not detected with computed tomography (CT) and/or magnetic resonance imaging (MRI) in three cases. The MIBG findings in the group with apparently sporadic paragangliomas (n = 6) were negative in four cases and failed to detect a cervical lesion in one multifocal paraganglioma.

CONCLUSION

(131)MIBG was useful in confirming the diagnosis in phaeochromocytomas with low levels of catecholamine secretion. It contributed little to the management of patients when used as a means of screening for multifocality in sporadic phaeochromocytoma, or the management of patients with familial phaeochromocytoma. However, MIBG can be an informative method of investigation when dealing with malignant/ectopic forms, although the sensitivity of MIBG is lower in this group of patients.