False-positive lymph nodes by radioimmunoguided surgery: report of a patient and analysis of the problem.

Abstract

Preoperative administration of radiolabeled monoclonal antibody allows radioimmunoguided surgery with hand-held intraoperative detection devices. From a theoretical perspective, this technology may offer more knowledgable patient management and more complete resection of intra-abdominal cancer. False-positive examinations may seriously jeopardize the widespread application of this apparatus. Our experience with a patient with false-positive lymph nodes following administration of 125I-labeled B72.3 monoclonal antibody is reported. After careful histopathological analysis of five nodes thought to be false-positive for cystadenocarcinoma, one lymph node was found to have a minute nidus of cancer. The cause of false-positive radioimmunoguided tests and their implications for the clinical use of this tool is discussed. We interpreted our data to suggest that tumor antigen-monoclonal antibody complexes processed in reactive lymph nodes, anatomically draining the malignant tissue, may cause false-positive tests.