Biliopancreatic diversion (BPD) creates a biliopancreatic limb that is inaccessible to conventional endoscopic surveillance, and its long-term neoplastic risk is unknown. A woman in her late 40 s presented 25 years after BPD with recurrent protein malnutrition and subocclusive symptoms. Computed tomography showed jejunal intussusception. At surgery, the intussusception was localized to the proximal biliopancreatic limb, 10–20 cm from the ligament of Treitz and remote from the entero-enterostomy. A 2.6-cm tubulovillous adenoma with focal high-grade dysplasia was found at the corresponding site and was completely excised. This appears to be the first reported high-grade dysplastic adenoma in an excluded biliopancreatic limb after BPD. The finding shows that a conventional dysplastic adenoma can arise in this compartment and makes an adenoma-carcinoma pathway biologically plausible, but a single case cannot establish causality, incidence, or risk in other bariatric procedures. Routine imaging surveillance is not supported by current evidence. However, an intussusception remote from the entero-enterostomy, particularly when associated with recurrent obstructive symptoms, warrants evaluation for a structural lead point.
