Gastric Chief Cell Adenomas: Proposal for a New Entity
Stuti Shroff, Melissa Taggart, Asif Rashid, Taofic Mounajjed, Tsung-Teh Wu, Susan Abraham. MD Anderson Cancer Center, Houston; Mayo Clinic, Rochester
Background: Chief cell predominant adenocarcinoma (CCP-AD) is a rare type of gastric carcinoma characterized by phenotypic and immunophenotypic differentiation toward chief cells. These tumors demonstrate low proliferative rates, lack of p53 overexpression, and less aggressive behavior as compared to usual gastric carcinomas. CCP-AD has only recently been described and its morphologic precursor is unknown.
Design: We studied 16 polyps from 10 patients who underwent gastric biopsy (n=7) or resection (n=3). Cases were collected prospectively because of their unusual histology (cytologic dysplasia and architectural atypia of chief cell predominant deep fundic glands). Age, gender, polyp size, morphology, multiplicity, concomitant adenocarcinoma, other gastric polyps, and results of immunohistochemistry for Ki67 and p53 were recorded.
Results: Lesions were centered in the basal aspect of oxyntic mucosa and comprised primarily of chief cells with moderately enlarged nuclei. Involved glands were mildly dilated with budding/anastomosing architecture (n=8), cribriforming (n=1), multilayered cells (n=14), luminal apoptotic debris (n=2), and inspissated basophilic secretions (n=2). In 6 cases, glands were admixed with splayed muscularis mucosae and 2 extended into superficial submucosa. Four lesions also had foveolar dysplasia and one of these abutted a submucosally-invasive CCP-AD. Ki67 immunostaining demonstrated abnormal extension of the proliferative zone down into the deep glandular compartment, although the proliferative rate was low (≤5%). p53 was negative.
|Age||Sex||No. polyps||Size||Other lesions|
|49||M||3||Largest 0.5 cm||FGPs x7|
|36||M||1||1.7 cm||Chief cell predominant adenocarcinoma|
|66||M||1||0.2 cm||FGPs x2|
|73||M||1||0.8 cm||FGPs x3|
|80||M||3||Largest 0.7 cm||No|
|71||M||5||Largest 0.45 cm||Foveolar adenoma and dysplastic FGP|