Case Reports in Gastrointestinal Medicine

Case Reports in Gastrointestinal Medicine / 2021 / Article

Case Report | Open Access

Volume 2021 |Article ID 6617370 | https://doi.org/10.1155/2021/6617370

Takehiro Tanaka, Kenji Nishida, Masaya Iwamuro, Satoru Kikuchi, Tadashi Yoshino, "A Case of Myoepithelial Hamartoma: Morphological Variation Supported by OCT4 Expression", Case Reports in Gastrointestinal Medicine, vol. 2021, Article ID 6617370, 5 pages, 2021. https://doi.org/10.1155/2021/6617370

A Case of Myoepithelial Hamartoma: Morphological Variation Supported by OCT4 Expression

Academic Editor: Hirotada Akiho
Received03 Oct 2020
Revised18 Feb 2021
Accepted21 Feb 2021
Published26 Feb 2021

Abstract

In this report, we describe a patient with myoepithelial hamartoma, which is regarded as synonymous with adenomyosis and heterotopic pancreas. Endoscopy revealed a submucosal tumor in the antrum of the stomach. Subsequently, distal gastrectomy with Roux-en-Y reconstruction was performed. Histological findings of adenomyomatous lesion and heterotopic pancreatic tissue were observed in this lesion. The distribution of OCT4, which is a pluripotency marker, varied in each part.

1. Introduction

Submucosal tumors of the stomach are rare, with the exception of gastrointestinal stromal tumors and lymphomas. Myoepithelial hamartoma (MEH) was described in 5 cases for the first time by Magnus–Alsleben in 1903 [1]. MEHs can occur anywhere in the gastrointestinal tract, but they most commonly occur in the antrum of the stomach [25]. Histologically, an MEH is composed of hypertrophic smooth muscle bands surrounding diverse epithelial elements such as cystic glandular structures, pyloric glands, and pancreatic acini [6]. MEHs are regarded as synonymous with heterotopic pancreas [7, 8].

We report the case of a patient who presented with abdominal pain and MEH and discuss the association between adenomyoma and heterotopic pancreas.

2. Case Presentation

A 39-year-old woman visited the previous hospital with a chief complaint of abdominal pain that lasted for a week. She had no history of gastrointestinal diseases. Subsequently, she underwent esophagogastroduodenoscopy, which revealed a submucosal tumor in the gastric antrum and a duodenal ulcer scar. Computed tomographic scanning showed wall thickening of the gastric antrum, after which the patient was referred to our hospital for further investigation and treatment. Esophagogastroduodenoscopy at our hospital revealed a pedunculated mass resembling a submucosal tumor in the antrum of the stomach (Figure 1(a)). Endoscopic ultrasonography revealed that the lesion was located in the submucosa and muscularis propria, and the mass was poorly defined and hypoechogenic (Figure 1(b)). Based on these findings, the presence of a gastrointestinal stromal tumor was suspected. Thus, an endoscopic ultrasonography-fine needle aspiration biopsy was performed for investigating the lesion. However, histological examination did not provide a diagnosis as the biopsy specimens revealed the presence of a small number of c-kit-negative spindle cells. Subsequently, distal gastrectomy with Roux-en-Y reconstruction was performed.

The lesion was located in the gastric antrum and duodenum and was 3.7 cm long (Figure 2). The resected specimen showed a vague nodule with dilated glands surrounded by edematous stroma in the submucosa and muscularis propria (Figure 3(a)). Its appearance was similar to that of uterine adenomyosis (Figure 3(b)). Histologically, the mass was composed of several types of glands, acini, and smooth muscle bundles. Some ducts were simply dilated glands, but the remaining were more organoid, composed of large ducts surrounded by radially extending acini and small ducts resembling Brunner or pyloric glands (Figure 3(b)). In several areas, a transition from ductal epithelium to mucous gland epithelium was noted in the same structure. Lymphocytic infiltration was found around the dilated ducts, and abscess formation was also observed around a few ducts. The overlying mucosa showed reactive changes consisting of hypertrophic foveola and a mild atrophy of the pyloric glands. Furthermore, no cytological atypia, goblet cells, or pancreatic islets were identified. Immunohistochemically, the simple dilated glands’ epithelium was positive for MUC6. OCT 4, which is a pluripotency marker, was not identified in the cells of the dilated glands (Figure 4). In the organoid pattern area, large ducts were negative for both MUC5AC and MUC6, and the surrounding small ducts were MUC6-positive but negative for MUC5AC (Figure 5). Furthermore, acinar cells tested positive for trypsin (Figure 4). A small population of small gland cells was positive for OCT4 (Figure 5). Test for INSM-1 did not outline aggregates of endocrine cells.

3. Discussion

We reported the presence of an MEH with various histological features. MEH is synonymous with adenomyosis and ectopic pancreas. In this case, there were two histological components: “adenomyosis,” in which only the ductal structure that expanded to the smooth muscle bundle was seen and “heterotopic pancreas,” ducts, and acini. Although different names have been given due to the differences in histological findings, we essentially have the same two types of lesions; both components appear in the same lesion in this case.

In this study, OCT4-positive cells were not found in the adenomyosis part; they were found in the part showing a more organoid structure. OCT4 is a pluripotency marker [911], suggesting that pluripotent cells may be required for the differentiation into pancreatic tissue. This result suggests that the presence or absence of pluripotent cells results in differences in tissue organization.

There is a theory that heterotopic pancreas is a stray pancreatic tissue during embryonic development [1214]; however, in some cases such as adenomyosis where the pancreatic tissue is not identified, it is difficult to explain its presence. On the contrary, the findings of acinar metaplasia of gastric mucosa are occasionally observed in type A gastritis, where the pluripotent cells in the stomach are differentiated to various degrees, and the result of hyperplasia is the essence of the lesion. Thus, we believe that the name “myoepithelial hamartoma” is appropriate [15].

Neoplastic lesions arising from ectopic pancreatic tissue have been reported [16, 17], most of which are adenocarcinomas similar to pancreatic ductal carcinoma; however, there are also reports of acinar cell carcinomas [18] and neuroendocrine tumors [19].

Mucosal incision-assisted biopsy (MIAB) is powerful method for the diagnosis of subepithelial lesions [20, 21]; we might have tried MIAB after EUS-FNA failure, but the patient’s symptom got worse, and hence, we decided to have surgery. The lesion was located from the antrum of stomach to the bulbus of duodenum across the pylorus, and distal gastrectomy was selected for the treatment instead of laparoscopic and endoscopic cooperative surgery (LECS) [22].

To our knowledge, no studies have reported the distribution of OCT4 in such tumors; however, analysis of cases is needed to explain the tumor genesis. Since there are many mysteries about the development of MEH, further examination is needed with regard to it.

The patient gave the written informed consent for submitting the case report.

Conflicts of Interest

The authors declare that they have no conflicts of interest.

References

  1. E. Magnus-Alsleben, “Adenomyome des pylorus,” Virchows Archiv für Pathologische Anatomie und Physiologie und für Klinische Medizin, vol. 173, no. 1, pp. 137–155, 1903. View at: Publisher Site | Google Scholar
  2. R. Ikegami, Y. Watanabe, and T. Tainaka, “Myoepithelial hamartoma causing small-bowel intussusception: a case report and literature review,” Pediatric Surgery International, vol. 22, pp. 387–389, 2005. View at: Google Scholar
  3. A. Trifan, E. Târcoveanu, M. Danciu, C. Huţanaşu, C. Cojocariu, and C. Stanciu, “Gastric heterotopic pancreas: an unusual case and review of the literature,” Journal of Gastrointestinal and Liver Diseases: JGLD, vol. 21, no. 2, pp. 209–212, 2012. View at: Google Scholar
  4. E. J. Zarling, “Gastric adenomyoma with coincidental pancreatic rest: a case report,” Gastrointestinal Endoscopy, vol. 27, no. 3, pp. 175–177, 1981. View at: Publisher Site | Google Scholar
  5. A. Ryan, J. R. Lafnitzegger, D. H. Lin, S. Jakate, and E. D. Staren, “Myoepithelial hamartoma of the duodenal wall,” Virchows Archiv, vol. 432, no. 2, pp. 191–194, 1998. View at: Publisher Site | Google Scholar
  6. A. Vandelli, G. Cariani, G. Bonora, F. Padovani, L. Saragoni, and D. Dell’Amore, “Adenomyoma of the stomach,” Surgical Endoscopy, vol. 7, no. 3, pp. 185–187, 1993. View at: Publisher Site | Google Scholar
  7. P. Teresa Rosanna, M. Francesco, V. Salvatore et al., “Myoepithelial hamartoma of the stomach simulating a gastric carcinoma: a case report,” Tumori, vol. 93, pp. 220–222, 2007. View at: Google Scholar
  8. P. Babal, M. Zaviačič, and L. Danihel, “Evidence that adenomyoma of the duodenum is ectopic pancreas,” Histopathology, vol. 33, pp. 485–494, 1998. View at: Publisher Site | Google Scholar
  9. S. P. Medvedev, A. I. Shevchenko, N. A. Mazurok, and S. M. Zakiian, “OCT4 and NANOG are the key genes in the system of pluripotency maintenance in mammalian cells,” Genetika, vol. 44, pp. 1589–1608, 2008. View at: Publisher Site | Google Scholar
  10. Y. Wang, G. Lanzoni, G. Carpino et al., “Biliary tree stem cells, precursors to pancreatic committed progenitors: evidence for possible life-long pancreatic organogenesis,” Stem Cells, vol. 31, no. 9, pp. 1966–1979, 2013. View at: Publisher Site | Google Scholar
  11. S. Stefanovic, N. Abboud, S. Désilets, D. Nury, C. Cowan, and M. Pucéat, “Interplay of Oct4 with Sox2 and Sox17: a molecular switch from stem cell pluripotency to specifying a cardiac fate,” Journal of Cell Biology, vol. 186, no. 5, pp. 665–673, 2009. View at: Publisher Site | Google Scholar
  12. H. Yamagiwa, N. Onishi, and M. Nishii, “Heterotopic pancreas of the stomach,” Pathology International, vol. 42, no. 4, pp. 249–254, 1992. View at: Publisher Site | Google Scholar
  13. T. Terada, “Heterotopic pancreatic tissue of the stomach: report of three cases and consideration of its histogenesis,” Case Reports in Gastroenterology, vol. 4, no. 3, pp. 386–392, 2010. View at: Publisher Site | Google Scholar
  14. R. Filip, E. Walczak, J. Huk et al., “Heterotopic pancreatic tissue in the gastric cardia: a case report and literature review,” World Journal of Gastroenterology, vol. 20, no. 44, pp. 16779–16781, 2014. View at: Publisher Site | Google Scholar
  15. Y. Takahashi and T. Fukusato, “Adenomyoma of the small intestine,” World Journal of Gastrointestinal Pathophysiology, vol. 2, no. 6, pp. 88–92, 2011. View at: Publisher Site | Google Scholar
  16. C. R. Chapple, S. Muller, and J. Newman, “Gastric adenocarcinoma associated with adenomyoma of the stomach,” Postgraduate Medical Journal, vol. 64, no. 756, pp. 801–803, 1988. View at: Publisher Site | Google Scholar
  17. D. E. Song, Y. Kwon, K.-R. Kim, S. T. Oh, and J.-S. Kim, “Adenocarcinoma arising in gastric heterotopic pancreas: a case report,” Journal of Korean Medical Science, vol. 19, no. 1, pp. 145–148, 2004. View at: Publisher Site | Google Scholar
  18. Y. Sun and P. G. Wasserman, “Acinar cell carcinoma arising in the stomach: a case report with literature review,” Human Pathology, vol. 35, no. 2, pp. 263–265, 2004. View at: Publisher Site | Google Scholar
  19. T. Tanaka, R. Omote, N. Okazaki, H. Yanai, and T. Yoshino, “Gastric neuroendocrine tumor arising from heterotopic pancreas,” Clinical Journal of Gastroenterology, vol. 11, no. 1, pp. 34–37, 2018. View at: Publisher Site | Google Scholar
  20. T. Osoegawa, Y. Minoda, E. Ihara et al., “Mucosal incision‐assisted biopsy versus endoscopic ultrasound‐guided fine‐needle aspiration with a rapid on‐site evaluation for gastric subepithelial lesions: a randomized cross‐over study,” Digestive Endoscopy, vol. 31, no. 4, pp. 413–421, 2019. View at: Publisher Site | Google Scholar
  21. Y. Minoda, T. Chinen, T. Osoegawa et al., “Superiority of mucosal incision-assisted biopsy over ultrasound-guided fine needle aspiration biopsy in diagnosing small gastric subepithelial lesions: a propensity score matching analysis,” BMC Gastroenterology, vol. 20, no. 1, 2020. View at: Publisher Site | Google Scholar
  22. T. Matsuda, S. Nunobe, T. Kosuga et al., “Laparoscopic and luminal endoscopic cooperative surgery can be a standard treatment for submucosal tumors of the stomach: a retrospective multicenter study,” Endoscopy, vol. 49, no. 5, pp. 476–483, 2017. View at: Publisher Site | Google Scholar

Copyright © 2021 Takehiro Tanaka et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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