Intraoperative indocyanine green with ultrasound-guided localization as prodigious adjuncts explicating negative margin in functional insulinoma: A case report

Introduction and importance: Insulinomas are rare pancreatic neuroendocrine neoplasms with an incidence of one to four cases per million annually and a 5 % to 10 % association with hereditary multiple endocrine neoplasia type-1. While most insulinomas are benign and well-encapsulated, approximately 6 % may have malignant potential. Intraoperative localization remains a vital component of treatment, often facilitated by modern imaging techniques like intraoperative ultrasound and fluorescence modalities.

Case presentation: A 52-year-old woman was referred to Kathmandu Medical College with generalized weakness, recurrent headaches, and fatigue relieved by food intake. She had a history of hypoglycemia-induced abnormal body movements and loss of consciousness. After biochemical and imaging evaluations, she was diagnosed with pancreatic insulinoma. Based on the higher affinity of neuroendocrine tumoral cells for Indocyanine Green compared to normal pancreatic cells, the patient underwent Indocyanine Green-directed laparoscopic-assisted pancreaticoduodenectomy managed perioperatively with subcutaneous octreotide. She had an uneventful postoperative period and was discharged on the eighth day.

Discussion: Insulinomas present a unique diagnostic and therapeutic challenge, especially in cases of sporadic occurrence. Surgical resection is the mainstay of treatment, with enucleation preferred for benign tumors. In this case, fluorescence-guided surgery and intraoperative ultrasound aided in accurate localization and successful excision.

Conclusion: Insulinomas, though rare, require prompt diagnosis and surgical intervention to prevent malignancy and metastasis.