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Pathology Research International
Volume 2010 (2010), Article ID 614280, 4 pages
Case Report

Idiopathic Hypertrophic Pyloric Stenosis in an Adult, a Potential Mimic of Gastric Carcinoma

1Department of Pathology and Laboratory Medicine, Allegheny General Hospital/Drexel University College of Medicine, 320 East North Avenue, Pittsburgh, PA 15212, USA
2Department of Pathology and Laboratory Medicine, Ohio State University Medical Center, S-305 Rhodes Hall 450 W. 10th Avenue, Columbus, OH 43310-1228, USA
3Department of Pathology and Laboratory Medicine, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Ave, Toronto, ON, Canada M5N 4M3

Received 24 May 2009; Accepted 24 July 2009

Academic Editor: Pablo A. Bejarano

Copyright © 2010 Alireza Zarineh et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Primary or idiopathic hypertrophy of the pyloric muscle (IHPM) is a rare entity with uncertain pathogenesis which both clinically and pathologically mimics gastric cancer. We present a rare late-occurring case of IHPM in a 71-year-old Caucasian man with no apparent predisposing factor. Imaging studies demonstrated gastric distension with air fluid levels and no evidence of extrinsic compression. At upper endoscopy, massive gastric distension and no evidence of any ulcer or other mucosal defects were observed. Microscopically, marked hypertrophy of muscularis mucosa with smooth muscle cells arranged in whorls and fascicles was present which gradually transitioned to normal areas. The muscle fibers stained with smooth muscle actin and trichrome stain highlighted fibrosis between the muscle fibers. Although uncommon, IHPM can clinically and histologically mimic other proliferations in the gastric wall, such as gastrointestinal stromal tumor or a spindle cell neoplasm. The recent advances in understanding the pathogenesis of IHPM are discussed.