TC-99M METHOXYISOBUTYLISONITRILE LOCALIZES AN ECTOPIC ACTH-PRODUCING TUMOR - CASE-REPORT AND REVIEW OF THE LITERATURE

Extensive investigation including whole-body examinations with compute d tomography and magnetic resonance imaging did not detect the suspect ed ectopic ACTH-producing tumour in a patient with advanced Cushing's syndrome and hypokalemic alkalosis. Gamma camera examination with tech netium-99m methoxyisobutylisonitrile (MIBI) depicted the tumour, which was localized in the anterior neck and mediastinum. This was later ve rified by surgery. Tc-99m-MIBI is normally used for myocardial scintig raphy. Its accumulation is unspecific and merely reflects metabolic ac tivity. Despite this, the present case shows that examination with thi s agent can provide important information with regard to tumour locali zation in a given situation, thereby serving as a complement to other imaging modalities. The current literature on Tc-99m-MIBI for tumour d iagnosis is reviewed.