Elsevier

Human Pathology

Volume 40, Issue 5, May 2009, Pages 746-749
Human Pathology

Case study
Pancreatic-type acinar cell carcinoma of the stomach beneath a focus of pancreatic metaplasia of the gastric mucosa

https://doi.org/10.1016/j.humpath.2008.10.006Get rights and content

Summary

Acinar cell carcinoma is an uncommon type of carcinoma of the pancreas that can exceptionally arise in ectopic pancreatic tissue. Herein, we report a case of a 52-year-old man with pancreatic-type acinar cell carcinoma of the stomach and concomitant pancreatic metaplasia of the adjacent nonneoplastic gastric mucosa. There was neither clinical nor radiographic evidence of a tumor in the pancreas itself. A subtotal gastrectomy was performed. Macroscopically, an ulcerated tumor, measuring 4 × 1.7 cm, was found in the distal antrum. Microscopically, the biopsy and the surgical specimen revealed a neoplasm with a predominantly trabecular architecture composed of moderately atypical cells with finely dispersed chromatin and indistinct nucleoli. The neoplastic cells and those of the adjacent metaplastic mucosa were both strongly immunoreactive for alpha-1-antitrypsin, consistent with pancreatic acinar cell differentiation. Ectopic pancreatic-type acinar cell carcinoma is an extremely rare condition, having been previously reported only in 5 occasions, none of them in association with pancreatic acinar cell metaplasia of the gastric mucosa.

Introduction

Pancreatic carcinomas of both exocrine and endocrine type can rarely arise in ectopic sites, where they can be misinterpreted as metastatic tumors. There are more than 30 cases of ectopic pancreatic carcinomas reported in the literature, most of them diagnosed as ductal adenocarcinomas [1], [2]. Most were located in the stomach and were contiguous to ectopic pancreatic nonneoplastic tissue. Acinar cell carcinoma is a rare neoplasm of the exocrine pancreas [3]. Five cases of pancreatic carcinomas with acinar cell differentiation have been described in ectopic sites, in only one of them accompanied by nonneoplastic pancreatic heterotopic tissue [4], [5], [6], [7], [8]. Herein, we report a case of pancreatic-type acinar cell carcinoma associated with adjacent pancreatic metaplasia of the gastric mucosa.

Section snippets

Materials and methods

The biopsy and surgical specimen materials were fixed in neutral buffered formalin and processed according to standard methods. Hematoxylin and eosin stains were performed on 3- to 4-μm-thick sections of formalin-fixed, paraffin-embedded material. Other formalin-fixed, paraffin-embedded sections were immunostained with the panel of antibodies listed in Table 1. A commercially available detection kit (Dako EnVision Plus-HRP, Dako, Glostrup, Denmark) was used according to the manufacturers'

Clinical features

A 52-year-old man presented for recently exacerbated dyspeptic symptoms. He had a history of duodenal ulcer and reflux esophagitis with sliding hiatal hernia. Gastroscopy showed a 7 mm ulcerated lesion in the gastric antrum. Multiple mucosal biopsies were obtained. Histologic examination revealed a poorly differentiated adenocarcinoma and chronic gastritis. Abdominal computed tomography scan, abdominal ultrasound, and thoracic radiography were all negative. The patient underwent a subtotal

Pathological features

The preoperative biopsy material revealed a neoplastic proliferation composed of epithelial cells predominantly arranged in trabecular structures with focal acinar and glandular formations. The cells were atypical, with enlarged overlapping nuclei and slightly dispersed chromatin. Some of the adjacent nonneoplastic glands exhibited a granular, slightly eosinophilic cytoplasm, which was intensely positive for PAS (periodic acid Schiff). The tumor was initially interpreted as a poorly

Discussion

The case herein described represents a pancreatic-type acinar cell carcinoma associated with—and presumably derived from—pancreatic metaplasia of the gastric mucosa. Some of the morphological features of the tumor as seen in the hematoxylin and eosin sections, such as the predominantly trabecular pattern of growth and the finely dispersed chromatin, raised the alternative possibility of a gastric or pancreatic neuroendocrine neoplasm [9]. However, the complete negativity for neuroendocrine

Acknowledgments

The authors wish to thank Dr Juan Rosai for reviewing the case and revising the manuscript.

References (17)

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