Abstract
BackgroundThe majority of gastrointestinal tumors are adenocarcinomas. Rarely, there are other types of tumors, such as acinar cell carcinoma, and these are often called pancreatic-type acinar cell carcinomas. Among these tumors, some are differentiated into neuroendocrine components. A few of them are MiNENs.Case presentationThe patient was an 80-year-old male who was referred to our hospital for treatment of a pedunculated gastric tumor. It was 5 cm in diameter and detected in the upper gastric body with upper GI endoscopy conducted to investigate anemia. In the biopsy, although hyperplasia of gastric gland cells was noted, no tumor cells were found. Retrospectively, the diagnosis was misdiagnosed. An operation was arranged because bleeding from the tumor was suspected as a cause of anemia and because surgical resection was considered to be desirable for accurate diagnosis. Hence, laparoscopic and endoscopic cooperative surgery was performed. In the pathological examination, several types of epithelial cells that proliferated in the area between the mucosa and deep inside the submucosa were observed. These consisted of acinar-glandular/trabecular patterns and solid. A diagnosis of pancreatic-type acinar cell carcinoma of the stomach with NET G2 and G3 was made based on characteristic cellular findings and the results of immunostaining tests. Each of them consisted of more than 30% of the lesion; a diagnosis of pancreatic-type mixed acinar neuroendocrine carcinoma (pancreatic-type MiNEN) of the stomach or a type of gastric MiNEN was obtained. Anemia was resolved after the operation, and the patient was discharged from the hospital without perioperative complications.ConclusionsPancreatic-type ACC of the stomach that is differentiated into neuroendocrine tumors is very rare. Hence, we report this case along with a literature review.
Highlights
The majority of gastrointestinal tumors are adenocarcinomas
Pancreatic-type Acinar cell carcinoma (ACC) of the stomach that is differentiated into neuroendocrine tumors is very rare
In 2019, the World Health Organization (WHO) classification of neuroendocrine neoplasms was modified; mixed neuroendocrinenonneuroendocrine neoplasms (MiNENs) are mixed epithelial neoplasms in which a neuroendocrine component is combined with a nonneuroendocrine component, each of which is morphologically and immunohistochemically recognizable as a discrete component and constitutes > 30% of the neoplasm [4]
Summary
Acinar cell carcinoma (ACC) is a rare type of tumor that makes up 1–2% of pancreatic tumors [1]. Significant atypical cells were rare for each type, the characteristics of the nuclei and nucleoli of the cells mentioned above and irregularity of the border of the lesion in the mucosa or the superficial layer led us to the idea that the lesion may be acinar cell carcinoma with some neuroendocrine features. To confirm this idea, immunostaining was performed using various pancreas-related markers or neuroendocrine markers. Regarding the tumor tissues presenting acinarglandular and trabecular patterns, a diagnosis of pancreatic-type acinar cell carcinoma of the stomach was made according to the characteristic findings, such as clear and swollen nucleoli and the results of immunostaining tests.
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