Neuroendocrine Carcinoma of the Stomach

Abstract

Neuroendocrine carcinoma (NEC) of the stomach has been recognized as a highly malignant tumor; however, because of its rarity, limited information is available regarding its clinicopathologic characteristics. Here, we investigated the morphologic and immunohistochemical features and prognosis of 51 cases of gastric NEC. Histologically, 40 lesions were large cell type, and 11 were small cell type. The large majority of the tumors exhibited a solid growth pattern (94%), with subsets of tumors showing trabecular (18%), scirrhous (10%), or tubular growth patterns (6%). Thirty-six cases (71%) had adenocarcinoma components and/or dysplasia. Among them, 26 cases (51%) were associated with intramucosal adenocarcinoma or dysplasia. Immunohistochemically, synaptophysin, chromogranin A, and CD56 were diffusely expressed in 48 (94%), 44 (86%), and 24 cases (47%), respectively. Two recently reported neuroendocrine markers, ASH1 and NKX2.2, were diffusely positive in 12 (24%) and 17 cases (33%), respectively. The diffuse or focal expression of TTF-1 was observed in 19 cases (37%). Among the 41 patients who underwent a curative resection, 16 patients (39%) developed radiologic recurrences, and the liver was the most frequent site of recurrence (11 patients, 27%). The 3- and 5-year overall survival rates were 57.8% and 44.7%, respectively. Regarding patient outcome, none of the histologic subclassifications, including small cell versus large cell types and the presence versus the absence of adenocarcinoma components and/or dysplasia, were significant. In a multivariate analysis, curative surgery was identified as the sole independent prognostic factor (P=0.03). Although gastric NECs exhibit significant morphologic diversity, their histologic subclassification is unlikely to be of immediate clinical relevance.

Prognostic Evaluations Tailored to Specific Gastric Neuroendocrine Neoplasms: Analysis Of 200 Cases with Extended Follow-Up

“…pdNECs, formerly known as poorly differentiated endocrine carcinomas or PDECs [48], are a well-characterized neoplastic disease with an ominous prognosis also in the stomach [8, 14, 16]. They closely reproduce histologic and immunohistochemical features, including a high rate of p53 protein and a low rate of somatostatin receptor expression, reported in corresponding pdNECs arising in the colon, pancreas, or other tissues [17, 46, 47].…”

Three Molecular Subtypes of Gastric Adenocarcinoma Have Distinct Histochemical Features Reflecting Epstein-Barr Virus Infection Status and Neuroendocrine Differentiation

“…It is frequently under-recognized because of the broad morphologic spectrum (from classic small cell carcinoma to poorly defined large cell carcinoma) and overlap with poorly differentiated adenocarcinoma 33,34,35,36 . Admixed adenocarcinoma components can be found in tumors of any of the neuroendocrine carcinoma subtypes, presenting a challenge in terms of the overall tumor classification.…”

Gastric Mixed Adenoneuroendocrine Carcinoma Occurring 50 Years after a Gastroenterostomy with Braun Anastomosis

“…Gastric NEC is an uncommon tumor, which reportedly comprises 0.1–0.6% of gastric cancers [10] and typically possesses adenocarcinoma components [4]. Definitive diagnosis of mixed NEC by endoscopic biopsy is thought to be difficult; in previous reports, the adenocarcinoma portion covered the surface mucosa [11], while the NEC developed in the submucosa and deeper layers [12].…”

“…One proposed theory is that the enterogastric reflux of bile and pancreatic secretions chronically irritate the gastric mucosa promoting neoplasia [1]. Gastric neuroendocrine carcinoma (NEC) is an uncommon tumor with a strong malignant potential and an extremely poor prognosis [4]. In the present case report, we describe a patient who had undergone GE with Braun enteroenterostomy (BEE) 50 years prior to presentation and had developed a mixed adenoneuroendocrine carcinoma (MANEC) at the anastomotic site.…”