Fifteen patients with medullary carcinoma of the thyroid (MCT), who had persistently elevated levels of serum calcitonin (CT) and carcinoembryonic antigen (CEA) after total thyroidectomy, were studied in order to localize the sites of the recurrent disease. Routine diagnostic examinations, including ultrasonography (US) and computed axial tomography (CAT), were carried out in all the cases. Scintigraphy with radio-iodinated meta-iodobenzylguanidine ((131I)-MIBG) was performed in 13 cases; selective venous catheterization (SVC) to reveal a gradient of CT levels was performed in 12 cases. Ten patients underwent both (l31I)-MIBG scintigraphy and SVC. US and CAT revealed the sites of recurrent tumor in only 4 out of the total 15 patients. SVC in basal conditions showed the presence of small metastases in 2 cases, and after intravenous stimulus with pentagastrin in 4 others. The MIBG scan showed metastatic foci of sporadic MCT in 2 patients, residual medullary thyroid tissue in 4 others, and a pheochromocytoma in a previously undiagnosed patient with Sipple's syndrome. More particularly, MIBG scan and SVC showed the localization of residual or metastatic tumor in 10 cases. In all 10 cases, results of the MIBG scan and SVC were confirmed as true positive by subsequent surgery and histopathologic examination. The conclusions of this study were twofold: (1) in the follow-up of MCT patients with persistently elevated CT and CEA levels, positive US and CAT findings make the MIBG scan useful, if positive, only to determine the nature of the lesion; (2) the association of the two approaches (MIBG scan and SVC) in patients with increased levels of CT and CEA but negative results of routine diagnostic examination can be useful to detect occult rnicrometastases, thus permitting an accurate clinicopathologic staging of the disease.
- Medullary thyroid carcinoma
- Selective venous catheterization
ASJC Scopus subject areas
- Pharmacology, Toxicology and Pharmaceutics(all)
- Pharmacology (medical)