Fluorescence-guided lymph node identification for biopsy for suspected lymphoproliferative disease or excision of lymph node recurrence

PURPOSE: To evaluate the feasibility of indocyanine green (ICG) fluorescence as an intraoperative tool for abdominal lymph-node localization in cases where fine needle aspiration cytology (FNAC), is not feasible. ICG was administered either 24 hours before surgery or at anaesthesia induction, and fluorescence findings were descriptively compared with preoperative imaging and histology. MATERIALS AND METHODS: This is a retrospective exploratory feasibility study. Patients undergoing excision of primary or metastatic lesions in areas not suitable for ultrasound-guided biopsy were included. Suspicious findings on computed tomography (CT) scan were confirmed with positron emission tomography (PET)-CT preoperatively. According to intravenous ICG administration, patients were divided into two groups: group A, 24-hours before surgery, and group B, at anaesthesia induction. Fluorescence visualization was descriptively assessed in relation to PET-CT findings and histology. RESULTS: Eight patients were included in group A and nine in group B. ICG fluorescence enabled intraoperative visualization of 13 out of 17 lesions overall (76.5%), including six out of eight in group A (75%), and seven out of nine in group B (77.8%), including retroperitoneal, mesenteric, and supraclavicular locations. Because PET-CT positivity was part of the inclusion pathway, descriptive concordance indicators are reported for descriptive purposes only. Visualization rates were comparable between the two protocols. CONCLUSIONS: Fluorescence appears to be a feasible and safe intraoperative adjunct for lymph-node identification in anatomically challenging regions. Administration at anaesthesia induction simplifies perioperative workflow while maintaining similar visualization rates. These findings are exploratory and hypothesis-generating and should be interpreted considering the small sample size and the selection bias related to PET-positive inclusion criteria.