Localized giant inflammatory polyp of the colon in a patient without inflammatory bowel disease

Abstract

Dear Editor, Gastrointestinal polyps are classified as neoplastic polyps, such as adenoma or polypoid adenocarcinoma, and non-neoplastic polyps of which inflammatory polyps may be regarded as a distinct entity [1]. Within the colon, inflammatory polyps have mainly been described to occur against a background of inflammatory bowel disease (IBD). Rarely, these lesions lead to stenosis, thereby mimicking a malignant tumor [2, 3]. But inflammatory polyps may also be observed in patients without history of IBD [4]. An asymptomatic 45-year-old male underwent routine colonoscopy because of a family history of colorectal cancer. There was no history of IBD. During colonoscopy, an irregular polypoid mass was detected at the hepatic flexure. Repeated biopsies showed chronic inflammation without evidence of malignancy. Prompted by the patient's positive family history and the suspicious endoscopic appearance of the lesion, a right-sided hemicolectomy was performed. On gross inspection, an irregular villous polyp, measuring 4 cm in largest diameter was found. The lesion showed circumferential growth and extended with small polyps of gradually decreasing size into the neighboring normal mucosa (Fig. 1a). Histological examination revealed irregular villous-like projections of the mucosa (Fig. 1b). The crypt architecture was markedly distorted, and the lamina propria contained a dense mixed inflammatory infiltrate. Crypt abscesses as well as hyperplastic lymphoid follicles were frequently observed, while epithelial dysplasia was lacking (Fig. 1c). One slide showed a circumscribed superficial ulcer which was bordered by unspecific granulation tissue. The nonpolypoid mucosa of the resection specimen was entirely normal, without signs of inflammation, particularly IBD. Finally, a diagnosis of “localized giant inflammatory polyp” was made. Localized giant pseudopolyps were first described in 1968 [5]. These lesions are almost invariably associated with IBD [2, 3]. Our case, however, clearly demonstrates that these lesions may also occur in patients without history of IBD. Moreover, the flat mucosa of the resection specimen was entirely normal, lacking signs of chronic inflammation. There is only a single report in the literature illustrating a case similar to ours. Tan et al. [4] reported upon a 64-year-old male without history of IBD who E.-M. Wolf : C. Strasser : E. Spuller : C. Langner (*) Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8036 Graz, Austria e-mail: cord.langner@medunigraz.at