The purpose of this study is to assess the feasibility and safety of ICG-guided intraoperative lymphography for detecting sentinel lymph nodes (SLN) in pediatric patients with solid tumors who require retroperitoneal lymph node dissection/sampling.

This trial is a single-site cross-sectional study. The injection of ICG directly into lymphatics draining the primary tumor will take place at the time of operation after the patient is under anesthesia.

Inclusion Criteria:

• Any pediatric patient (under the age of 18 years) being treated at the University of Rochester Medical Center, Department of Surgery.
• Diagnosed with pediatric solid tumor
• Scheduled to undergo lymph node sampling as part of their clinical management.

Exclusion Criteria:

• Subjects with a history of iodide allergies.
• Inability or unwillingness of research participant or parent/legal guardian to give written informed consent.
• Currently pregnant.
• Infants under 650 grams.
• Patients with extensive prior surgery at the primary site or nodal basin expected to affect the lymphatic drainage.

Pediatric patients aged 1 month to 17 years with diagnosed solid tumors who are receiving care at the University of Rochester Medical Center (URMC), Department of Surgery. Eligible participants are those scheduled to undergo lymph node sampling as part of standard clinical management. Participants will be identified through pediatric oncology, pediatric surgery, and tumor board evaluations.