Gastric Pouch Mixed Adenoneuroendocrine Carcinoma With a Mixed Adenocarcinoma Component After Roux-en-Y Gastric Bypass

Abstract

The Roux-en-Y gastric bypass is one of the most common procedures currently performed for surgical treatment of patients with severe obesity. Gastric cancer after bariatric surgery is not common, with most of them arising in the excluded stomach. Gastric mixed adenoneuroendocrine carcinomas are a rare type of stomach malignancy, composed of both adenocarcinoma and neuroendocrine tumor-cell components, with the latter comprising at least 30% of the whole neoplasm. In this article, we report a unique case of a mixed adenoneuroendocrine carcinoma with a mixed adenocarcinoma (tubular and poorly cohesive) component arising in the gastric pouch of a patient who underwent previous Roux-en-Y gastric bypass for glycemic control. Since stomach cancer is not usual in patients who have formerly undergone bariatric surgery and symptoms tend to be nonspecific, such diagnosis is often rendered at an advanced stage. Full assessment of these patients when presenting such vague symptoms is critical for an early cancer diagnosis.

Mixed Neuroendocrine Non-Neuroendocrine Neoplasms: A Systematic Review of a Controversial and Underestimated Diagnosis

“…The quantitative composition of the primary tumour was described in 36 studies (n = 294) [12,15,17,19,21,[23][24][25]27,29,30,34,36,[39][40][41]45,46,[48][49][50][52][53][54]56,57,59,65,73,74,80,82,[84][85][86]92]; the two components were present in equal proportion in 27.9% (n = 82) of cases, whereas in the remaining 72.1% one of the two histologies was predominant; the neuroendocrine component in 42.2% (n = 124), the non-neuroendocrine component in 29.9% (n = 88).…”

“…Among 69 studies (n = 667) reporting the grade of differentiation of the neuroendocrine component [11][12][13][14][15][16][17][18][19][21][22][23][24][25][26][27][28][29][54][55][56][57][58][59][60][61][62]68,71,[73][74][75]79,80,82,[84][85][86][87]89,[91][92][93]96,97,100,101], a large proportion of MiNENs (92.5%; n = 617) had a grade 3 neuroendocrine component, whereas 4.3% (n = 29) and 3.1% (n = 21) had a grade 1 and a grade 2 neuroendocrine component, respectively. Among MiNENs with a grade 3 neuroendocrine component, the morphological subtype (large cell or small cell) was reported in 25 studies (n = 241) [11,…”

“…Interestingly, in 43 studies (n = 61) where more than one diagnostic sample was available [11,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]30,[32][33][34][36][37][38][39][41][42][43][44][45][46][47]49,50,53,55,[59][60][61][62]64,65,96], the initial diagnosis from the first sample collected (either cytological or histological) was in keeping with MiNEN or suspicion of MiNEN in 36.1% (n = 22) of cases, adenocarcinoma in 36.1% (n = 22), poorly differentiated neuroendocrine carcinoma in 21.3% (n = 13), and well differentiated neuroendocrine tumour in 6.6% (n = 4).…”

“…The histology of synchronous or metachronous distant metastases was reported in 14 studies (N = 51) [11,17,22,31,50,57,58,[62][63][64]85,86,92,96], and was consistent with a single or predominant poorly differentiated neuroendocrine component in 60.8% (n = 31) of cases, with a mixture of a neuroendocrine carcinoma and an adenocarcinoma in 33.3% (n = 17), and a single or predominant adenocarcinoma component in 5.9% (n = 3).…”

Prognostic factors for survival after curative resection of gastric mixed adenoneuroendocrine carcinoma: a series of 80 patients

“…The pathology of gMANEC indicates that its clinical and biological characteristics differ from those of simple gastric neuroendocrine carcinoma and simple gastric adenocarcinoma [ 5 ]. However, due to the low incidence of gMANEC, few gMANEC studies have been performed, most of which analyze only a single or a few patients [ 6 – 8 ]. In addition, no guidelines currently exist for gMANEC patients, as the 2017 National Comprehensive Cancer Network guidelines do not address gMANEC treatment, and factors affecting gMANEC prognosis and treatment have not yet been reported.…”