Heterotopic pancreas in the omphalomesenteric duct remnant in a 9-month-old girl: a case report and literature review

BACKGROUND Heterotopic pancreas most commonly occurs in the upper gastrointestinal tract of adults, usually as an incidental finding. It seldom occurs at the umbilicus, and even rarely in the pediatric age group. CASE PRESENTATION Here we present a case of heterotopic pancreatic tissue in the omphalomesenteric duct remnant of a 9-month-old baby girl. She presented with redness at the base of the umbilicus associated with occasional mild wetness. A urachal fistula was suspected by ultrasound. Histology from subsequent resection revealed fibrous tissue with heterotopic pancreatic tissue and accompanying small bowel mucosa. The patient's umbilical redness resolved after the surgery. CONCLUSIONS Upon literature search, we found only 17 other cases of heterotopic pancreas reported in the umbilicus. They described a high male to female ratio, frequent association with omphalomesenteric duct remnant and presentation of umbilical discharge. The Heinrich system is frequently used to classify heterotopic pancreas into 3 types, based on the presence of acini, islets and ducts. Several mechanisms have been proposed on the pathogenesis of heterotopic pancreas, including misplacement, metaplasia and totipotent cell theories. Heterotopic pancreas can manifest clinically with diseases of the pancreas, including malignant transformation, reported as high as 12.7% in a series. Awareness of this finding in the biopsy aids the suitable treatment decisions for the patient.