Gastrointestinal: A Prolapsing Mucosal Polyp Protruding From the Small Bowel Diverticulum Causing Intestinal Bleeding

A 65-year-old female patient was admitted with a two-week history of bloody stools, dizziness, and fatigue. The patient has a 10-year history of hypertension and underwent coronary stent implantation 2 years ago. She has been taking aspirin, metoprolol succinate, rosuvastatin calcium, nicorandil and other medications regularly. The patient's vital signs remain stable, and no significant positive physical signs were found during the abdominal examination. Laboratory tests revealed decreased levels of red blood cell count at 2.39 × 1012/L, hemoglobin concentration at 54 g/L, and mean corpuscular volume at 76.3 fL. Additionally, there were increased enzymatic activities, with pro-brain natriuretic peptide measured at 381.3 ng/L. The patient was administered a treatment of three units of red blood cells. Gastrointestinal endoscopy showed no significant hemorrhagic lesions. A CT scan later identified a sausage-shaped, heterogeneous soft tissue mass in the ileum, containing lipid components and having well-defined margins, locally adhered to the small intestinal wall (Figure 1a,b). Small intestinal endoscopy revealed an oval tumor measuring approximately 30 × 60 mm with rostral ulceration and an irregular surface; its base was adjacent to an ileal diverticulum (Figure 2a,b). This lesion was determined to be the source of bleeding. The biopsy pathology indicates hyperplasia of granulation tissue, accompanied by both acute and chronic inflammatory cell infiltration. Additionally, localized epithelial cell hyperplasia is observed in a limited quantity. This finding excludes the possibility of malignant lesions. Given the substantial size of the lesion and the potential risk of hemorrhage, the patient subsequently underwent a laparotomy for the resection of a small intestinal tumor followed by intestinal anastomosis (Figures 3). Postoperative histopathological analysis indicated fibrous tissue and smooth muscle proliferation in the lamina propria, along with hyperplasia of local granulation tissue and infiltration by acute and chronic inflammatory cells (Figures 4). Immunohistochemical staining was positive for CK and CK8/18. Based on these findings, a diagnosis of ileal prolapsing mucosal polyp (PMP) was established. The patient's recovery was eventful. She was discharged after 1 week and has been followed up to date without any discomfort. PMP is a rare benign lesion that primarily affects the colorectum; however, its involvement in the small intestine is uncommon. These polyps are histologically classified as unclassified polyps, akin to those observed in mucosal prolapse syndrome [1]. It is believed that their formation results from chronic intermittent ischemia due to either obvious or concealed mucosal prolapse. Similarly, most of the mucosal prolapse-like polyps found in the colon are associated with diverticula, where redundant mucosa becomes forced into polypoid folds within thickened segments of the intestinal wall [2]. In this case, we performed enteroscopy to observe the lesion in the ileum. The irregularity and ulceration of the lesion made us suspect a neoplastic polyp, although the biopsy pathology presented no basis for malignancy. However, the correct diagnosis still depends on the acquisition of postoperative specimens [3]. Currently, there is no evidence to suggest malignant transformation of such lesions. For patients with large lesions that result in bleeding or obstructive symptoms and are not amenable to endoscopic resection, surgical intervention remains a viable option. To the best of our knowledge, this report represents the first detailed account of a polypoid lesion originating from ileal diverticula. It is crucial for endoscopists to be well-acquainted with and adept at recognizing the characteristic features associated with this type of lesion. When faced with polypoid lesions in the small intestine that are linked to diverticula, it is vital to consider the possible existence of such lesions. This study was supported by the Shandong Provincial Medical and Health Science and Technology Development Program Project (202203031070). Informed consent was obtained from the patient. The authors declare no conflicts of interest.