Background: Heterotopic pancreas, also referred to as ectopic pancreas, is a rare congenital anomaly
defined by the presence of pancreatic tissue outside its normal anatomical location without ductal or
vascular continuity with the orthotopic pancreas. Although frequently asymptomatic and discovered
incidentally, heterotopic pancreas is capable of undergoing the same pathological processes as native
pancreatic tissue, including premalignant and malignant transformation. Pancreatic intraepithelial
neoplasia (PanIN) arising in heterotopic pancreatic tissue is uncommon, particularly within the jejunum.
Case Presentation: A 65-year-old woman presented with a six-month history of intermittent upper
abdominal pain. Cross-sectional imaging demonstrated a well-circumscribed submucosal mass in the
distal jejunum with nonspecific radiologic features, raising concern for neoplasia. Segmental jejunal
resection was performed. Histopathologic examination revealed heterotopic pancreas, Heinrich
type I, composed of pancreatic acini, ducts, and islets within the jejunal submucosa and muscularis
propria. Focal low-grade pancreatic intraepithelial neoplasia (PanIN-1) involving ductal structures
was identified. No high-grade dysplasia or invasive carcinoma was present, and surgical margins were
negative.
Conclusion: This case highlights the diagnostic challenges associated with jejunal heterotopic pancreas
and demonstrates that ectopic pancreatic tissue can harbor premalignant ductal lesions analogous to
those seen in the orthotopic pancreas. Recognition of this rare entity is important, as definitive diagnosis
relies on histopathologic evaluation, and complete surgical excision is curative for low-grade lesions in
the absence of invasive malignancy.
