DOI: 10.12809/hkmj134189
PICTORIAL MEDICINE
Inflammatory myoglandular polyps of the rectum
Akira Hokama, MD#; Chiharu Kobashigawa, MD#; Jiro Fujita, MD
Department of Infectious, Respiratory, and Digestive Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
# Currently at Department of Endoscopy, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
 
Corresponding author: Dr Akira Hokama (hokama-a@med.u-ryukyu.ac.jp)
 
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Case report
An 84-year-old woman with advanced pharyngeal cancer underwent colonoscopy for intermittent rectal bleeding in October 2012. Colonoscopy disclosed two red sessile polyps in the rectum (Fig 1). The larger one was spherical with a smooth surface, measuring approximately 15 mm in diameter (Fig 2). Biopsy showed hyperplastic glands and marked proliferation of smooth muscle cells in the lamina propria, consistent with a diagnosis of inflammatory myoglandular polyp (IMGP) [Fig 3]. The patient denied colonoscopic treatment and stays in a hospice.
 

Figure 1. Colonoscopy disclosing two red sessile polyps in the rectum
 

Figure 2. The larger polyp is spherical with a smooth surface, measuring approximately 15 mm in diameter
 

Figure 3. Biopsy shows hyperplastic glands and marked proliferation of smooth muscle cells in the lamina propria, consistent with a diagnosis of inflammatory myoglandular polyp (H&E; original magnification, x 100)
 
Inflammatory myoglandular polyp is a rare, non-neoplastic polyp of the colorectum with histological features of inflammatory granulation tissue in the lamina propria, proliferation of smooth muscle cells, and hyperplastic glands with variable cystic changes.1 Since Nakamura et al1 first documented IMGP in 1992, only 60 cases of IMGPs have been reported worldwide.2 As most IMGPs are located in the rectum and the sigmoid colon, a common symptom of the condition is haematochezia. Although the causes of IMGP are obscure, chronic trauma from the faecal stream and peristalsis may contribute to its pathogenesis.1 With prolonged irritation, small, sessile IMGPs can enlarge and become pedunculated. Characteristic features include hyperaemic surface with patchy mucous exudation and erosion. Inflammatory myoglandular polyp differs from other non-neoplastic polyps including inflammatory cap polyps, inflammatory cloacogenic polyps, juvenile polyps, inflammatory fibroid polyps, polyps secondary to mucosal prolapse syndrome, polypoid prolapsing mucosal folds of diverticular disease in terms of its clinical and histopathological features.2 Most IMGPs can be treated by endoscopic resection. Because IMGP follows a benign course, endoscopic resection might be unnecessary when biopsy confirms the histopathological diagnosis.3
 
References
1. Nakamura S, Kino I, Akagi T. Inflammatory myoglandular polyps of the colon and rectum. A clinicopathological study of 32 pedunculated polyps, distinct from other types of polyps. Am J Surg Pathol 1992;16:772-9. CrossRef
2. Meniconi RL, Caronna R, Benedetti M, et al. Inflammatory myoglandular polyp of the cecum: case report and review of literature. BMC Gastroenterol 2010;10:10. CrossRef
3. Hirasaki S, Okuda M, Kudo K, Suzuki S, Shirakawa A. Inflammatory myoglandular polyp causing hematochezia. World J Gastroenterol 2008;14:5353-5. CrossRef
 
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