title: Mucosal colonization of gastric endocrine tumors mimicking mixed neoplasms.
abstract: Two cases of gastric tumors showing mixed composition of endocrine cell clusters and exocrine glands and originally diagnosed as mixed neoplasms are described. In both cases, the exocrine glandular component was restricted to the upper third of the neoplasms being consistently absent in areas of muscular wall invasion and, in case 2, in nodal metastases. These glands were in close anatomical contiguity with the glands of the overlying gastric mucosa or, in case 1, apparently derived from deep pouch-like invaginations of the mucosa. They showed either lack of dysplasia (case 1) or mild dysplasia (case 2) with a Ki67 proliferation index consistently lower than that of the intramucosal glands. The intratumoral glands presented intestinal metaplastic features confirmed by intense Cdx2 immunostaining that, conversely, was absent in the endocrine component of the tumors. The latter showed intense vesicular monoamine transporter 2 immunoreactivity consistent with its origin from the enterochromaffin-like cells of the gastric oxyntic mucosa. On the basis of these findings, it is proposed that the exocrine glands do not represent a true neoplastic component of the tumors. Although mucosal entrapment by the tumor cannot be ruled out, they more likely reflect a hitherto unrecognized mechanism of mucosal colonization of gastric endocrine tumors.
authors: Department of Pathology and Laboratory Medicine, University of Parma, 14 via Gramsci., 43100, Parma, Italy.
authors: Tu Vinh
authors: TV
authors: Luong
authors: Emanuela
authors: E
authors: Pilozzi
authors: Italo
authors: I
authors: Bearzi
authors: Cesare
authors: C
authors: Bordi
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D000071616:CDX2 Transcription Factor; D002276:Carcinoid Tumor / Q000378:metabolism / Q000556:secondary* / Q000601:surgery; D049109:Cell Proliferation; D003937:Diagnosis, Differential; D004759:Enterochromaffin Cells / Q000378:metabolism / Q000473:pathology*; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007422:Intestines / Q000473:pathology; D019394:Ki-67 Antigen / Q000378:metabolism; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008679:Metaplasia; D008875:Middle Aged; D018198:Mixed Tumor, Malignant / Q000175:diagnosis*; D013274:Stomach Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D050493:Vesicular Monoamine Transport Proteins / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D000071616:CDX2 Transcription Factor; C491270:CDX2 protein, human; D018398:Homeodomain Proteins; D019394:Ki-67 Antigen; D050493:Vesicular Monoamine Transport Proteins