□ CASE REPORT □

Heterotopic in the which Caused Obstructive Stenosis in the

Shinya Kobayashi 1, Yasutaka Okayama 2, Kazuki Hayashi 1, Hitoshi Sano 1, Shigehiro Shiraki 1, Kazuo Goto 2, Hirotaka Ohara 1 and Takashi Joh 1

Abstract

The patient, a 43-year-old Japanese man suffering from duodenal ulcer and reflux esophagitis, was admit- ted to our hospital because of submucosal tumor in the antrum and obstructive stenosis of duodenum. Several imaging tests could not rule out the possibility of malignant disease. Therefore, the patient was surgically treated. Pathohistological examination of resected tissue demonstrated Heinrich type I heterotopic pancreas in the gastric lesion and submucosal abscess in the duodenal lesion with stenosis . In this case, it was consid- ered that the heterotopic pancreas caused chronic inflammation to form the gastric tumor, and submucosal abscess leading to the severe duodenal stenosis.

Key words: Heinrich type I, submucosal abscess, chronic inflammation, duodenal stenosis, gastric tumor

(DOI: 10.2169/internalmedicine.45.1814)

duodenal ulcer and reflux esophagitis. The patient was ad- Introduction mitted to our hospital, because obstructive stenosis in the duodenum was found during follow-up study for duodenal Most cases of heterotopic pancreas in the stomach are en- ulcer by gastrointestinal radiologic examination and gastro- doscopically detected by chance because patients with this duodenoendoscopic study. He had no remarkable symptom. disorder are typically asymptomatic. Treatment is not gener- Physical examinations on admission did not demonstrate any ally required. Therefore, heterotopic pancreas in the stomach abnormalities, nor did laboratory data on admission. Anemia is not a great problem in the clinical setting. was not found on peripheral blood examination, and inflam- Here, we report a very rare case of heterotopic pancreas matory reaction was not observed on biochemical blood in the stomach, which caused an obstructive duodenal steno- analysis. Serum levels of tumor markers (CEA, AFP, CA19- sis. Surgical treatment was performed and histological ex- 9, DUPAN II, and SPAN-1), pancreatic enzymes (AMY, aminations demonstrated that heterotopic pancreas located in trypsin, lipase, elastase 1, and PSTI), and gastrin were all the gastric antrum caused chronic inflammation around the normal. Upper gastrointestinal radiologic examination dem- heterotopic pancreatic tissue to form a submucosal tumor in onstrated dilation failure in the gastric antrum and the duo- the antrum, and resulted in the formation of a submucosal denal bulb, as well as stenosis over the entire circumference abscess in the duodenum. This duodenal abscess was con- of the post-bulbal part of the duodenum (Fig. 1a, b). Al- sidered to have caused duodenal stenosis. though endoscopic study demonstrated an elevated lesion at the posterior wall of the antrum, there was erosion in the Case Report surface of the lesion. These findings indicated that this le- sion was formed by a submucosal tumor or extrinsic pres- The patient was a 43-year-old Japanese man. Three years sure. The duodenal bulb was severely narrowed. Redness previously, he complained of epigastralgia and heartburn, and erosions were observed in the mucosa of duodenal bulb, and received ambulatory treatment based on the diagnosis of but endoscope could not be inserted into the anal site

１ Department of Internal Medicine and Bioregulation, Nagoya City University Graduate School of Medical Sciences, Nagoya and ２ Department of Gastroenterology, Gifu Prefectural Tajimi Hospital, Tajimi Received for publication March 12, 2006; Accepted for publication July 26, 2006 Correspondence to Dr. Shinya Kobayashi, Department of Internal Medicine, Aichi Kouseiren Asuke Hospital, 20 Yagami-chou, Toyota, Aichi 444-2351

1137 DOI: 10.2169/internalmedicine.45.1814

Figure 1. a) Upper gastrointestinal radiologic examination demonstrated dilation failure in the gastric antrum and the duodenal bulb. b) Stenosis over the entire circumference of the post bulbal part of the duodenum.

Figure 2. a) Upper gastrointestinal endoscopic study demonstrated extrinsic pressure between the greater curvature of the antrum and the posterior wall, there was erosion in the center of sub- mucosal tumor. b) The duodenal bulb was narrowed, and redness and erosions were observed in the duodenal mucosa.

(Fig. 2a, b). Biopsies obtained from the duodenal bulb suggested that duodenal stenosis was caused by a submu- showed no neoplasmic changes. Computed tomography (CT) cosal tumor of the antrum and/or the duodenum. In addition demonstrated a tumor measuring 4×5 cm between the gas- to the severity of stenosis, the possibility of malignant dis- tric antral and the duodenal wall, and a part of the tumor ease could not be ruled out. Therefore, the patient was sur- was densely stained with a contrast medium. No abnormal- gically treated. The tumor was palpated between the gastric ity was detected in the liver, the pancreas, or the antrum and the duodenal bulb intraoperatively. Rapid in- (Fig. 3a, b). Abdominal ultrasonography (US) did not dem- traoperative pathology did not demonstrate any malignant onstrate a clear tumor lesion detected by CT. These findings findings. Therefore, subtotal gastrectomy and partial duode-

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Figure 3. a) Plain computed tomography: showing a submucosal tumor between the gastric an- trum and the duodenum. b) Enhanced computed tomography: a part of the tumor was densely stained with a contrast medium.

Figure 4. a) b) The resected specimen showed a round tumor measuring 5×4cm (a: mucosa, b: se- rosa, arrows show pyloric ring). There was erosion in the gastric mucosa，and an ulcer and erosion were observed in the duodenal mucosa.

notomy were performed. When resected tissue specimens ined, there was no capsule and the inside of the tumor was were macroscopically examined, a round tumor measuring whitish and yellowish (Fig. 5a, b). Pathohistological findings 5×4 cm was observed at the region 4 cm from the duodenal demonstrated that the lesion was present between the proper stamp on the gastric serosa. There was erosion in the center muscular layer and the serosa of the stomach, while, in the of submucosal tumor (Fig. 4a, b). In addition, an ulcer and lesion, pancreatic tissue with acinar cells, duct cells, and is- erosions were observed in the duodenal mucosa, and the lets of Langerhans was observed (Fig. 6a, b). Therefore, the wall was hypertrophied. When fixed specimens were exam- patient was diagnosed as having Heinrich type I heterotopic

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num, 25% in the stomach, 15% in the , 3% in the , and 6% in Meckel diverticulum (1). Thus, almost half of the cases of heterotopic pancreas developed in the stomach and the duodenum. Moreover, they noted that het- erotopic pancreas was also observed in the , the common , the liver, and the . The frequency of heterotopic pancreas found in the resected stomach was also reported to range between 0.25 and 0.8% (2). It was also reported that heterotopic pancreas in the stomach pre- dominantly develops in male subjects between 30 and 50 years of age (the male-to-female ratio is 2-3:1). Most cases (90%) of heterotopic pancreas in the stomach are single, and are observed in the antrum. Moreover, heterotopic pancreas in the stomach macroscopically exhibit a morphology of submucosal tumor (3). Heinrich classification (4) is fre- quently used to classify this disorder, and it was reported that Heinrich type II, which consists of ascinar and duct cells excluding islets of Langerhans, was most frequently observed. Although it was reported that the symptoms of heterotopic pancreas in the stomach include epigastralgia, epigastric discomfort, nausea, and eructation, most cases fol- low asymptomatic courses (5, 6). Heterotopic pancreas in pediatric patients is generally detected as a small nodule measuring 1-2 mm in diameter. However, such a small nod- ule is reported to increase in size along with the growth of pediatric patients (7, 8). When such nodules increase in size at the pyloric zone of the stomach, the most common site of heterotopic pancreas, it may cause (9, 10). Moreover, although the frequency is lower than that in nor- mal pancreatic tissue, heterotopic pancreas was reported to induce secondary changes, such as acute or chronic pancrea- titis, bleeding, or cyst formation (11-15). A report has been Figure 5. a) b) Cut surface shows the whitish and yellowish published describing elevated serum amylase levels in pa- colored tumor with fibrosis. tients with heterotopic pancreatitis in the stomach. Although the levels of pancreatic enzymes were all normal in the pre- sent patient, it was considered that repeated inflammation pancreas in the stomach. The ratio of pancreatic tissue to the caused by heterotopic pancreas in the stomach resulted in entire tumor was limited. Most of the tumor consisted of tumor formation at the serosal side of the antrum. Submu- marked muscular hypertrophy, fiber proliferation, and lym- cosal abscess formation was observed in the duodenal region phocyte infiltration formed around the pancreatic tissue. with stenosis. Although the real reason for abscess formation Marked neutrophil proliferation was observed between the was unknown, it is conceivable that inflammation and tumor submucosal muscular layer and the proper muscular layer of formation around the gastric heterotopic pancreas may me- the duodenum, and submucosal abscess was formed in the chanically irritate the duodenal wall and cause bacterial in- duodenum (Fig. 6c). However, malignant findings were not fection to form a submucosal abscess. In this case, this ab- detected in any sections. Thus, in this case, chronic inflam- scess formation was considered to have caused duodenal mation appeared to be formed around the gastric heterotopic stenosis. To date, there have been no reports describing se- pancreas first, and then the submucosal abcess was induced vere duodenal stenosis induced by heterotopic pancreas in in the duodenum, which caused such an obstructive stenosis. the stomach. Therefore, the present case was considered to have been a very rare case of such a disorder. We would Discussion like to emphasize that when duodenal stenosis with gastric submucosal tumor has developed within a relatively short Pancreatic tissue is heterotopically observed in various ab- time, not only malignant diseases, but also inflammatory dominal organs, and termed, heterotopic pancreas, aberrant changes associated with gastric heterotopic pancreas should pancreas, or accessory pancreas. Pearson et al reviewed 589 be considered. cases of heterotopic pancreas, and reported the frequencies of this disorder in the abdominal region; 30% in the duode-

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Figure 6. a, b) Pancreatic tissue with acinar cells, duct cells, and islets of Langerhans was observed. (HE stain ×100) b) Arrow shows islet of Langerhans. c) Histologic examination of re- sected specimen demonstrated marked neutrophil proliferation between the muscular layer of mu- cosae and the proper muscular layer of the duodenum. Submucosal abscess was formed in the duodenum. (HE stain ×40)

References

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