IN-111-PENTETREOTIDE SCINTIGRAPHY IS SUPERIOR TO I-123 MIBG SCINTIGRAPHY IN THE DIAGNOSIS AND LOCATION OF CHEMODECTOMA

Chemodectomas, or glomus tumours, are unusual head and neck paragangli omas. A non-invasive imaging technique, I-123-metaiodobenzylguanidine (I-123-MIBG) scintigraphy, has long been used for the diagnosis of all types of paraganglioma. The aim of this study was to evaluate and com pare classic I-123-MIBG scintigraphy with the more recent In-111-pente treotide scintigraphy in the diagnosis and location of chemodectomas. We performed I-123-MIBG and In-111-pentetreotide scintigraphy in eight patients (7 females, 1 male) with histologically or radiologically co nfirmed chemodectomas (five carotid body and three jugulotympanic chem odectomas). I-123-MIBG uptake was visualized in four patients on plana r views and SPET images (sensitivity 50%); uptake was low in three pat ients. Using In-111-pentetreotide scintigraphy, all chemodectomas in t he eight patients were visualized (sensitivity 100%) and In-111-pentet reotide uptake was high in all cases. In conclusion, our results indic ate that In-111-pentetreotide scintigraphy is superior to I-123-MIBG s cintigraphy in the diagnosis and location of chemodectomas. In-111-pen tetreotide or I-123-MIBG uptake suggests a neuroendocrine origin, prov iding important functional information in the diagnosis of chemodectom as. Moreover, In-111-pentetreotide scintigraphy permits a good classif ication of patients with or without somatostatin receptors in the chem odectoma in the application of pharmacological therapy with somatostat in analogues to inoperable rumours. The main therapeutic action of col d somatostatin analogues is to inhibit hormonal hypersecretion in diff erent neuroendocrine tumours. In chemodectomas, however, the most impo rtant effect of somatostatin analogues is to reduce tumour volume or i nhibit growth progression ((C) 1998 Lippincott Williams & Wilkins).