[674] Morphologic Characterization of Gastric Polyps in Juvenile Polyposis and Peutz-Jeghers' Syndromes Versus Gastric Hyperplastic Polyps

D Lam-Himlin, JY Park, T Cornish, C Shi, E Montgomery. Johns Hopkins Hospital, Baltimore, MD

Background: Hamartomatous polyps from patients with Juvenile Polyposis Syndrome (JPS) and Peutz-Jeghers' Syndrome (PJS) are morphologically distinct in the small and large bowel, often aiding in diagnosis of these syndromes. Such syndromic gastric polyps, however, are not well characterized. We investigated the histologic features of gastric polyps in patients with JPS or PJS to develop improved histologic criteria to distinguish these from gastric hyperplastic (HP) polyps.
Design: Patients with clinically confirmed hamartomatous polyposis syndromes were identified, including 26 patients with JPS (both familial and sporadic) and 17 patients with PJS. All gastric polyps (n= 30) from these patients were intermixed with gastric HP polyps from non-syndromic patients (n=26) and subsequently blindly reviewed by a panel of gastrointestinal pathologists. A consensus diagnosis was rendered. Following re-review of the syndromic cases, the panel established histologic criteria for distinguishing JPS, PJS, and HP gastric polyps based on epithelial changes, glandular architecture, changes in lamina propria, and smooth muscle qualities. A “sleeping period” of two weeks lapsed before the same cases were re-numbered and blindly re-reviewed. Diagnoses were then rendered while adhering to the suggested criteria. Cases that the reviewers recalled were discarded from the study (n=8).
Results: On initial review, accuracy in diagnosis of gastric polyps in JPS was 50% and PJS 18%, compared to HP gastric polyps at 92%. Adherence to the recommended histologic criteria showed accuracy of JPS 20% and PJS 44%, compared to HP gastric polyps at 96%. Accuracy in diagnosis in antral mucosa was 77%, oxyntic mucosa 79%, and transitional-type mucosa (mixed antral and oxyntic) 25%. Diagnostic accuracy based on size was 70% for polyps ≤3mm, 69% 4–9mm, and 67% ≥10mm.
Conclusions: Identification of gastric polyps from JPS and PJS patients without the context of clinical history of these syndromes remains poor, even with adherence to a set of morphologic criteria developed by gastrointestinal pathologists reviewing such cases. Abiding by such criteria improved recognition of PJS polyps by more than double (p<0.19), but yielded an accuracy of only 44%. Accuracy did not improve when results were stratified for polyp location or biopsy size. Whereas these syndromic polyps are readily diagnosed in the small bowel and colon, histologic features to distinguish JPS and PJS from gastric HP polyps are unreliable in the gastric location.
Category: Gastrointestinal

Monday, March 22, 2010 1:00 PM

Poster Session II # 79, Monday Afternoon


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