Clinical features, diagnosis, and treatment of colorectal cap polyposis

doi:10.4240/wjgs.117526

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World Journal of Gastrointestinal Surgery

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1948-9366

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Baishideng Publishing Group Inc, 7041 Koll Center Parkway, Suite 160, Pleasanton, CA 94566, USA

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Copyright: ©Author(s) 2026. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial (CC BY-NC 4.0) license. No commercial re-use. See permissions. Published by Baishideng Publishing Group Inc.

World J Gastrointest Surg. Jun 27, 2026; 18(6): 117526
Published online Jun 27, 2026. doi: 10.4240/wjgs.117526

Clinical features, diagnosis, and treatment of colorectal cap polyposis

Wei Zhou, Sheng Dai, Kai Xu, Bing-Jun Bai, Si-Jie Yin, Jin-Lin Shan, Li-Na Shan

Li-Na Shan, Si-Jie Yin, Bing-Jun Bai, Kai Xu, Sheng Dai, Wei Zhou, Department of Colorectal Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, Zhejiang Province, China

Jin-Lin Shan, The Second School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou 310053, Zhejiang Province, China

Co-first authors: Li-Na Shan and Jin-Lin Shan.

Co-corresponding authors: Sheng Dai and Wei Zhou.

Author contributions: Shan LN and Shan JL contributed equally to this study in clinical data collection and manuscript drafting as first authors; Yin SJ coordinated pathological staining; Bai BJ validated histopathological findings; Xu K performed database management; Dai S and Zhou W conceived the study, provided clinical supervision, critically revised the manuscript, and serve as corresponding authors.

Supported by National Natural Science Foundation of China, No. 82373163.

Institutional review board statement: The study was reviewed and approved by the Ethics Committee of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine (Approval No. 2024-0669).

Informed consent statement: Written informed consent was obtained from all patients for the use of anonymized clinical data and publication of this report.

Conflict-of-interest statement: All authors declare no conflicts of interest related to this work.

Data sharing statement: Anonymized data supporting the findings of this study are available from the corresponding author upon reasonable request.

Corresponding author: Wei Zhou, PhD, Chief Physician, Department of Colorectal Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, No. 3 East Qingchun Road, Hangzhou 310016, Zhejiang Province, China. weizhou_srrsh@zju.edu.cn

Received: December 15, 2025
Revised: March 5, 2026
Accepted: April 8, 2026
Published online: June 27, 2026
Processing time: 189 Days and 18.7 Hours

Abstract

BACKGROUND

Cap polyposis (CP) is a rare benign colorectal disorder characterized by polyps capped with fibrinopurulent exudate and is frequently misdiagnosed as inflammatory bowel disease because of overlapping clinical and histological features. No consensus exists regarding optimal management strategies. The aim of this study was to establish a standardized stepwise management algorithm for CP based on lesion distribution, number, size, and symptom severity, with the hypothesis that such an approach will optimize therapeutic outcomes while minimizing unnecessary interventions.

AIM

To clarify the clinical features, endoscopic findings, treatments and short-term outcomes of colorectal CP and provide clinical information for the diagnosis and treatment of this rare disease.

METHODS

We retrospectively collected data from seven consecutive patients with histologically confirmed CP who were treated at our center between January 2022 and January 2025.

RESULTS

The cohort comprised six males and one female (median age 36 years). Hematochezia was the main symptom (n = 3), and two patients had hypoalbuminemia. Five patients had solitary lesions and two patients had multiple lesions. All the polyps had a characteristic “cap-like” appearance with white fibrinous exudate covering the surface. Histology revealed elongated, dilated crypts and mucosal hyperplasia covered by granulation tissue. One patient with small, asymptomatic lesions was kept under surveillance. Three patients underwent endoscopic mucosal resection, and three underwent transanal excision. Symptoms resolved in all treated patients. During a median follow-up of 18 months (range 10-30 m), no recurrence was detected.

CONCLUSION

In this small series, CP affected mainly males and resulted in rectal bleeding. Both endoscopic and transanal resection relieved symptoms, but larger studies with longer follow-up periods are needed to confirm long-term efficacy.

Keywords: Cap polyposis; Endoscopic resection; Transanal excision; Treatment; Stepwise management

Core Tip: Cap polyposis is a rare inflammatory colorectal disorder characterized by fibrinopurulent-capped polyps. Clinicians frequently misdiagnose it as inflammatory bowel disease. This study retrospectively analyzed seven patients and established a stepwise management algorithm based on lesion distribution, size, and symptoms. Endoscopic or transanal resection achieved sustained symptomatic relief in all treated patients. Protein-losing enteropathy resolved rapidly after definitive surgical intervention.