A Case of Pediatric Pancreatic Insulinoma Diagnosed 4 Years after the Onset

Insulinomas are rare tumors resulting in hyperinsulinemic hypoglycemia. Insulinomas are usually seen in adults, and are very rare in the pediatric population. A total of 10% of insulinomas that occur are associated with multiple endocrine neoplasia type 1, and overall, 10% are malignant.

A 12-year-old boy suffered from an absence-like condition, 4 years before presentation. It was later discovered that this was due to hypoglycemia. His fasting blood glucose level was normal (93 mg/dL), but his insulin level was 60.8 µIU/mL, and his C-peptide level was 4.25 ng/mL, at the first visit. Abdominal CT and MRI showed a 6-cm nodular lesion in the anterior part of the pancreatic tail. Somatostatin receptor scintigraphy revealed radiotracer accumulation in the tumor. There was no evidence of lymphadenopathy or distant metastasis. He underwent laparoscopic spleen-preserving distal pancreatectomy. Pancreatic pathology revealed a grade 2 neuroendocrine tumor and malignant insulinoma. Postoperatively, the patient had no further hypoglycemia. At 9 months after the operation, he was under careful follow-up observation.

We present a pediatric case of a malignant insulinoma that was preoperatively diagnosed as benign and subsequently treated by minimally invasive surgery. There is no clear treatment strategy for pediatric malignant insulinomas. We suggest that-even if malignant insulinoma has been treated by minimally invasive surgery-follow-up with surveillance imaging is acceptable if curative resection has been achieved; however, further surgical intervention may be warranted in selected cases.