Adenocarcinoma arising in association with gastric heterotopic pancreas: A case report and review of the literature

Abstract

We report a case of adenocarcinoma arising in a focus of heterotopic pancreas, occurring in the stomach of a 52-year-old man. The patient presented with gastric outlet obstruction. Radiographic studies revealed thickening of the gastric wall, but endoscopy failed to reveal a mucosal abnormality. A 50% distal gastrectomy was performed, along with vagotomy. Microscopic examination revealed extensive involvement of the muscularis propria of the distal stomach by heterotopic pancreas. The ectopic pancreas had a microscopic appearance consistent with Heinrich's class III, in which the majority of the heterotopic pancreas was characterized by cystically dilated duct structures. Occasional islets were present. Intimately associated with the cystically dilated ducts was a prominent number of small infiltrating ducts lined by columnar or cuboidal cells with enlarged hyperchromatic nuclei containing prominent nucleoli. These were consistent with a well-differentiated invasive adenocarcinoma. Despite multiple sectioning, no connection between the adenocarcinoma and the overlying gastric mucosa was seen. Adenocarcinoma arising within ectopic pancreas is a rare occurrence with fewer than 30 well-documented cases reported in the world literature to our knowledge.

Heterotopic pancreas in the stomach: A case report and literature review

“…Up to 15 cases have been reported so far [10] . In order to be described as arising from heterotopic pancreas, the diagnosis of a carcinoma should fulfil three criteria: (1) the tumour must be located within or very close to the ectopic pancreatic tissue, (2) transition between pancreatic structures and carcinoma must be identified and (3) the non-neoplastic pancreatic tissue must comprise fully developed acini and ducts [11] . Adenocarcinomas arising from ectopic pancreas seem to have a somewhat better prognosis than those arising from the pancreas itself, probably due to earlier presentation [10] .…”

Mucinous cyst exhibiting severe dysplasia in gastric heterotopic pancreas associated withe gastrointestinal stromal tumour

“…Heterotopic pancreas has been classified into three types by Heinrich: classⅠis typical pancreatic tissue with acini, ducts and islet cells, class Ⅱ shows a large number of acini and few ducts, and class Ⅲ shows numerous ducts with few acini or islet cells [5] . Neoplasms arising in heterotopic pancreatic tissue are rare [6] and include borderline mucinous cystic tumour [7] , adenocarcinoma [6] , mucinous cystadenocarcinoma [8] , acinar cell carcinoma [2] , islet cell tumour [9] , or solid and papillary neoplasm [10] . Cystic degeneration without malignant change appears to be more common and may mimic mucinous carcinoma from another primary site [11] .…”

Anaplastic Carcinoma Possibly Arising from a Heterotopic Pancreas

“…Most cases of heterotopic pancreas are asymptomatic and are found incidentally in the upper gastrointestinal tract (6). Cases of ectopic pancreas have been reported in a variety of other sites, including the omentum, mesocolon, and abdominal lymph nodes (7,8). Two hypotheses for the development of ectopic pancreas include anomalous separation of the developing pancreatic anlagen and the differentiation of totipotent endodermal cells into pancreatic tissue.…”

“…Thus, an ectopic pancreas could be found in numerous organs. In addition, the malignant transformation of an ectopic pancreas is also rare (8)(9)(10).…”