Advanced Gastric Neuroendocrine Carcinoma with an Adenocarcinoma Component

Abstract

In the present study, we observed that the adenocarcinoma component in the mucosa was continuous with neuroendocrine carcinoma (NEC) in the deeper layers; this suggests the normal course of NEC carcinogenesis at the histological level. A 72-year-old man was admitted to our hospital with a chief complaint of tarry stools. Endoscopic examination of the upper gastrointestinal tract revealed a 2-cm tumor, with a deep central depression, surrounded by a smooth elevated area, in the middle of the stomach body. A biopsy showed that the tumor was a moderately differentiated gastric adenocarcinoma. The patient underwent total gastrectomy and standard lymph node dissection. The resected tumor was a 3.5 × 2.5 cm type 2 lesion. It comprised two elements at the histological level: (i) a moderately differentiated adenocarcinoma in the superficial portion of the mucous membrane layer, and (ii) NEC-like cells with dark, round nuclei and scant cytoplasm, presenting a solid and trabecular pattern, in the submucosal and muscularis propria layers. Immunohistochemical findings showed that the NEC-like cells were diffusely positive for chromogranin A, synaptophysin, neural cell adhesion molecule, and neuron-specific enolase, but were negative for carcinoembryonic antigen. The Ki-67 labeling index was 95%. The final pathological diagnosis was gastric NEC with an adenocarcinoma component and a high cellular proliferative potential.

Gastric Mixed Adenoneuroendocrine Carcinoma with a Good Prognosis

“…Gastric NECs are considered to arise predominantly from endocrine precursor cell clones that develop in the preceding adenocarcinoma component rather than ECL cells. These clones transform into NEC lesions during rapid clonal expansion, while NEC tumors develop rapidly in the submucosal and deeper layers (4,5). In the present case, the endoscopic findings showed a reddish area of erosion, which corresponded to the adenocarcinoma component, and endoscopic ultrasonography revealed a hypoechoic mass in the submucosal layer, which reflected the NEC component.…”

Neuroendocrine carcinoma of the stomach: clinical features and CT findings

“…Moreover, it has been reported that the analysis of synaptophysin may be more sensitive compared with the distribution of chromogranin A [9].This conclusion is consistent with the findings of our study, as the positive rate of chromogranin A and synaptophysin being 77.28% and 86.36%, respectively. The tumor rarely occurs in the gastrointestinal tract, accounting for approximately 1% involved in the esophagus, 0.2% in the colon [5]. The incidence of NEC in the stomach is exceedingly rare.…”

“…G-NEC patients may present with epigastric pain or discomfort, dysphagia, nausea and vomiting, and hematochezia. Other features such as acid reflux [14], tarry stools [5] may also be present. Epigastric pain or discomfort is common because of the increased thickening of the gastric wall.…”

“…Similarly, our eighteen cases were misdiagnosed as gastric adenocarcinoma. Even though the biopsy through gastroscopy and colonoscopy are helpful to make a definitive diagnosis of G-NEC, a misdiagnosing is frequently observed [5,8,13,14]. This diagnosis problem is due to the rapid develop of adenocarcinoma in the submucosal and deeper layers as a precursor cell clones partly transformed into G-NEC [5].…”

“…Even though the biopsy through gastroscopy and colonoscopy are helpful to make a definitive diagnosis of G-NEC, a misdiagnosing is frequently observed [5,8,13,14]. This diagnosis problem is due to the rapid develop of adenocarcinoma in the submucosal and deeper layers as a precursor cell clones partly transformed into G-NEC [5]. The same author reported a case in which were included two elements at the histological level: an adenocarcinoma component in the superficial portion of the mucous membrane layer and NEC in the submucosal and muscularis propria layers.…”