Limited role of meta-iodobenzylguanidine scintigraphy in imaging phaeochromocytoma in patients with multiple endocrine neoplasia type II

Objective: To compare diagnostic applicability of combined computed tomography (CT) and magnetic resonance imaging (MRI), with that of meta-iodobenzylguanidine (MIBG) scintigraphy in the preoperative localisation of MEN II related phaeochromocytoma.

Design: Retrospective study

Setting: University hospital, The Netherlands.

Materials: 17 patients with MEN II patients (33 adrenal glands) who were operated on for phaeochromocytoma. MIBG scintigraphy, CT and MRI were used to localize phaeochromocytoma. Histopathologically, an adrenomedullary lesion more than 1 cm in size was classified as a phaeochromocytoma.

Main outcome measures: Sensitivity, specificity, and diagnostic accuracy of combined CT and MRI and MIBG scintigraphy, compared with histopathological findings.

Results: Sensitivity of combined CT and MRI (27 adrenal glands) was 87%, with a specificity of 100% and a diagnostic accuracy of 89%. MIBG scintigraphy (31 adrenal glands) had a sensitivity of 92%, a specificity of only 17%, and a diagnostic accuracy of 77%.

Conclusion: If unilateral adrenalectomy is done when only one adrenal gland contains a phaeochromocytoma, then MRI should be the method of choice for localising MEN type II related phaeochromocytoma. MIBG scintigraphy can be restricted to those patients in whom MRI does not show a tumour.