Inflammatory myoglandular polyp of the cecum: case report and review of literature

Abstract

Background: Inflammatory myoglandular polyp (IMGP) is a rare non-neoplastic polyp of the large bowel, commonly with a distal localization (rectosigmoid), obscure in its pathogenesis. Up till now, 60 cases of IMGP have been described in the literature, but none located in the cecum.

Case presentation: We report a case of a 53-year-old man who was admitted to our hospital for further evaluation of positive fecal occult blood test associated to anemia. A colonoscopy identified a red, sessile, lobulated polyp of the cecum, 4.2 cm in diameter, partially ulcerated. The histological examination of the biopsy revealed the presence of inflammatory granulation tissue with lymphocytic and eosinophil infiltration associated to a fibrous stroma: it was diagnosed as inflammatory fibroid polyp. Considering the polyp's features (absence of a peduncle and size) that could increase the risk of a polypectomy, a surgical resection was performed. Histological examination of the specimen revealed inflammatory granulation tissue in the lamina propria, hyperplastic glands with cystic dilatations, proliferation of smooth muscle and multiple erosions on the polyp surface: this polyp was finally diagnosed as IMGP. There was also another little polyp next to the ileocecal valve, not revealed at the colonoscopy, 0.8 cm in diameter, diagnosed as tubulovillous adenoma with low grade dysplasia.

Conclusions: This is the first case of IMGP of the cecum. It is a benign lesion of unknown pathogenesis and must be considered different from other non-neoplastic polyps of the large bowel such as inflammatory cap polyps (ICP), inflammatory cloacogenic polyps, juvenile polyps (JP), inflammatory fibroid polyps (IFP), polyps secondary to mucosal prolapse syndrome (MPS), polypoid prolapsing mucosal folds of diverticular disease. When symptomatic, IMGP should be removed endoscopically, whereas surgical resection is reserved only in selected patients as in our case.

Figure 1

Endoscopic view. Colonoscopy showing a red, sessile and lobulated polyp in the cecum. A biopsy is performed.

Figure 2

Surgical specimen: ileocecal resection. Surgical specimen: ileocecal resection. IMGP appears to be a spherical, sessile and lobulated polyp of the cecum, without a peduncle, 4.2 cm in diameter. An arrow shows a little adenomatous polyp below the IMGP next to the ileocecal valve.

Figure 3

Histological findings. Polyp's whole picture, showing cystic dilatations embedded in the fibromuscular stroma (A). Low power view of inflammatory granulation tissue and engorged capillaries in the lamina propria, hyperplastic glands with cystic dilatations and proliferation of smooth muscle from muscolaris mucosae (B, C). Diffuse positive immunostaining of smooth muscle actin (D). (A, B, C: hematossilin-eosin staining, A 1:1, B 2,5× obj, C 4× obj; D: anti-actin immunoperoxidase, 4× obj).