EARLY IMMUNOSCINTIGRAPHIC LOCALIZATION OF A MEDIASTINAL TUMOR WITH INDIUM 111-DTPA CEA-SPECIFIC F(AB')2 MONOCLONAL-ANTIBODY FRAGMENTS (BW 431/31) USING 2ND TRACER ISOCONTOUR TECHNIQUE

A female patient with steadily increasing carcinoembryonic antigen (CEA) serum levels of unknown origin was referred for immunoscintigraphy with indium 111-labelled CEA-specific monoclonal antibody. The procedure revealed a tumour, undetectable by conventional diagnostic methods. Anatomical landmarking using the second tracer isocontour technique allowed the distinction between an intra- or extrapulmonary lesion. Two months later, tumour infiltration along the aortic arch was confirmed by a targeted angio-CT scan. Upon surgery, the diagnosis was definitely established histologically (undifferentiated, solid large cell carcinoma, most probably arising from the bronchus), and staining by CEA-specific immunohistochemistry confirmed the presence of the CEA antigen. © 1990 Springer-Verlag.