DETECTION OF CERVICAL METASTASES OF THYROID MEDULLARY CARCINOMA BY MOAB ANTI-CEA SCINTIGRAPHY AND IMMUNOHISTOCHEMISTRY

Four patients with medullary thyroid carcinoma (MTC) were examined usi ng anti-carcinoembryonic antigen (CEA) scintigraphy. Two patients had positive and two normal scintigraphic findings, although all the patie nts had elevated blood test markers (calcitonin or CEA). One patient w ith clinical suspicion of MTC metastases had only a faintly positive a nti-CEA image, although single-photon emission tomographic scanning wa s used to increase the sensitivity and resolution of the method. There fore, digital image processing of the planar images was performed to o btain more detailed information. The analysis revealed distinct accumu lation of the activity at the right side of the neck at 20 h post admi nistration. The specificity of the antibody binding in the malignant c ells was confirmed after surgery by immunohistochemical staining of th e tumour specimens for CEA. Both conventional and confocal laser scann ing microscopy revealed distinct positive staining, indicating that th e results obtained from the anti-CEA scanning showed specific binding of the labelled antibody in the neoplastic tissue.