title: Pulmonary intestinal-type adenocarcinoma does not show enteric differentiation by immunohistochemical study.
abstract: Six cases of an unusual variant of primary pulmonary adenocarcinoma resembling colorectal and sinonasal adenocarcinoma are presented. Pulmonary intestinal-type adenocarcinoma occurs in elderly Caucasians and is associated with a histology characteristic of colorectal/enteric adenocarcinoma: a garland-like architecture with a 'gland in gland' periphery, central 'dirty' necrosis, and elongated stratified columnar cells, lacking significant goblet or signet ring differentiation. While a resemblance to intestinal adenocarcinoma by light microscopy is present, immunohistochemical studies comparing these carcinomas with metastatic colorectal adenocarcinoma clearly show a respiratory phenotype with the neoplastic cells expressing thyroid transcription factor-1 and cytokeratin 7 to the exclusion of cytokeratin 20, and failing to express CDX-2. Stains for a variety of epithelial mucins (MUC1, MUC2, MUC5AC) also support this observation. The differential diagnosis with other pulmonary adenocarcinomas, especially those with mucinous differentiation, is discussed.
authors.affiliation: Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213-2582, USA. yousemsa@upmc.edu
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Yousem
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology*; D000368:Aged; D000369:Aged, 80 and over; D000071616:CDX2 Transcription Factor; D002454:Cell Differentiation; D003110:Colonic Neoplasms / Q000473:pathology*; D005260:Female; D018398:Homeodomain Proteins / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000032:analysis; D053554:Keratin-20; D053552:Keratin-7; D007633:Keratins / Q000032:analysis; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D055271:Mucin 5AC; D018396:Mucin-1 / Q000032:analysis; D055262:Mucin-2; D009077:Mucins / Q000032:analysis; D009687:Nuclear Proteins / Q000032:analysis; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators / Q000032:analysis; D014157:Transcription Factors / Q000032:analysis
chemical_list: D000071616:CDX2 Transcription Factor; D018398:Homeodomain Proteins; D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; C507497:KRT7 protein, human; D053554:Keratin-20; D053552:Keratin-7; C524625:MUC2 protein, human; C524678:MUC5AC protein, human; D055271:Mucin 5AC; D018396:Mucin-1; D055262:Mucin-2; D009077:Mucins; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators; D014157:Transcription Factors; D007633:Keratins