131I-MIBG scintigraphy in neural crest tumours.

Radioiodinated meta-iodobenzylguanidine (131I-MIBG) has been widely used for the diagnosis of neuroblastomas, pheochromocytomas, paragangliomas and medullary carcinomas of thyroid. We have developed a procedure for preparation of 131I-MIBG and studied its utility in diagnosis of primary and metastatic neural crest tumours. Studies were carried out in 54 patients. Of them 39 cases were of neuroblastomas, 1 pheochromocytoma; 6 operated medullary carcinomas; 5 paragangliomas; 2 Ewing's sarcoma and 1 Rhabdomyosarcoma; The sensitivity for the detection of primary tumours of neuroblastomas was 94% and for the detection of metastasis was 83%; while in the case of paragangliomas and medullary carcinoma, the sensitivity was 75% and 70% respectively. Our experience in the present study shows that 131I-MIBG scintigraphy is a sensitive and specific diagnostic tool to localise primary and metastatic disease of neural crest tumours.

Localization of a pheochromocytoma using I-123 MIBG adrenal scintigraphy.

In a patient with the clinical diagnosis of pheochromocytoma, the localization of the tumor is essential for planning treatment. Recently, we have performed I-123 metaiodobenzylguanidine (MIBG) adrenal scintigraphy in a patient presenting with a history of paroxysmal hypertension. Scintigraphy accurately located an ectopic unilateral pheochromocytoma. The scintigraphic diagnosis was confirmed by surgery and a diagnosis of ectopic unilateral pheochromocytoma was made by histopathological examination. This case report illustrates the specific diagnosis of pheochromocytoma by I-123 MIBG scintigraphy which is especially useful when other diagnostic procedures are equivocal.