Misplacement of Dysplastic Epithelium in Peutz–Jeghers Polyps

Abstract

Peutz-Jeghers syndrome is characterized by multiple polyps throughout the gastrointestinal tract in association with mucocutaneous pigmentation. Small bowel polyps in the syndrome may exhibit epithelial misplacement, into the submucosa, the muscularis propria, and even the subserosa. The authors demonstrate two patients in whom there is also misplacement of dysplastic epithelium into the submucosa and muscularis propria of the small bowel. Epithelial misplacement is recognized to mimic invasive malignancy. Such mimicry is heightened substantially when the misplaced epithelium is dysplastic. Correct interpretation of the histologic changes is aided by the use of special stains, which demonstrate the associated lamina propria and the lack of a desmoplastic response, and immunohistochemistry, which shows that the misplaced dysplastic epithelium is accompanied by non-neoplastic mucosa. There is an increased prevalence of gastrointestinal malignancy in Peutz-Jeghers syndrome. However, the presence of perplexing histologic features, caused by epithelial misplacement, especially when some of that epithelium is dysplastic, in small bowel polyps at least has the potential for the overdiagnosis of malignancy in the syndrome.

Peutz-Jeghers Polyposis With Enteritis Cystica Profunda--a Diagnostic Pitfall

“…Awareness of ECP is important to avoid a wrong diagnosis, which would be disastrous for the patient. The biggest problem occurs when there are foci of adenomatous or dysplastic changes [17] within the PJ polyp. The misplaced epithelium may then be dysplastic.…”

Gastrointestinal Inherited Polyposis Syndromes

“…Misplaced epithelium occurs in approximately 10% of small bowel PJ polyps and appears to be a phenomenon confined to the small bowel lesions (36). A rare example with misplaced dysplastic epithelium has been reported (35). The benign nature of misplaced epithelium is recognized by the accompanying lamina propria investing the glands, regardless of the dysplastic or normal nature of the epithelium.…”

“…The benign nature of misplaced epithelium is recognized by the accompanying lamina propria investing the glands, regardless of the dysplastic or normal nature of the epithelium. As a rule, dysplasia within PJ polyps is rare, and most examples of benign misplaced epithelium in these polyps contain normal, nondysplastic epithelium (2,35,36).…”

Epithelial misplacement in the muscularis propria after biopsy of a colonic adenoma

“…Sir, Hyper-plastic and hamartomatous colonic polyps may show misplaced epithelium (pseudo-invasion) within the submucosa or more rarely even extending into the muscular wall and/or serosa, potentially simulating an invasion by a well-differentiated adenocarcinoma [2,4]. The pathogenesis of this condition is referred to as the passage of the mucosal glands through the anatomical defects in the muscularis mucosae due to tissue damage from torsion, or twisting, of the polyp [2,4].…”

“…The pathogenesis of this condition is referred to as the passage of the mucosal glands through the anatomical defects in the muscularis mucosae due to tissue damage from torsion, or twisting, of the polyp [2,4]. It is likely that even minor trauma, resulting from vigorous peristalsis or bulky intraluminal material, may be responsible of epithelial misplacement, especially in sessile polyp [4].…”