Endoscopic Mucosal Resection of a Large Rectal Juvenile Polyp in a 7-Year-Old Child: A Case Report

Summary

This report summarizes the diagnostic journey and surgical management of a large rectal retention polyp in a 7-year-old child. It details the standardized protocol for Endoscopic Mucosal Resection (EMR) to prevent diagnostic delays and demonstrate safe therapeutic intervention for large pediatric colorectal lesions.

Abstract

Pediatric hematochezia is a frequent clinical symptom that often poses a diagnostic challenge for gastroenterologists. This study presented the case of a 7-year-old female patient with a one-year history of intermittent hematochezia. Due to the painless nature of the bleeding, the condition was initially misdiagnosed as internal hemorrhoids by several clinics, leading to a year of ineffective conservative management. Upon admission via the emergency department, a comprehensive diagnostic workup was initiated. An abdominal contrast-enhanced three-dimensional computed tomography (3D CT) scan was prioritized to rapidly rule out life-threatening acute surgical abdomens. Subsequent diagnostic colonoscopy identified a large sub-pedunculated polyp, measuring 20 mm × 25 mm, located on the left rectal wall. The patient was successfully treated with Endoscopic Mucosal Resection (EMR) under intravenous general anesthesia. The procedure utilized a submucosal saline injection to create a protective fluid cushion, followed by high-frequency snare resection and mechanical closure with titanium clips. No immediate or delayed complications occurred. Histopathological analysis confirmed the diagnosis of a retention polyp, characterized by cystic glandular dilation and an inflammatory stroma. This case demonstrates that early endoscopic evaluation is critical for children with unexplained lower gastrointestinal bleeding. Furthermore, it highlights EMR as an illustrative and effective minimally invasive therapeutic option for managing large pediatric colorectal polyps, providing an excellent long-term prognosis.

Introduction

Lower gastrointestinal bleeding (LGIB) in the pediatric population represents a frequently encountered clinical scenario that poses significant diagnostic and therapeutic challenges for gastroenterologists worldwide¹. While many episodes of rectal bleeding in children are benign and self-limiting, persistent or recurrent hematochezia necessitates a rigorous and systematic diagnostic evaluation to identify the underlying etiology and prevent long-term sequelae². Among the diverse causes of pediatric LGIB, colorectal polyps are identified as the most prevalent etiology, accounting for approximately 12% to 15% of all pediatric patients presenting with significant rectal bleeding in clinical settings³. Within the histological spectrum of pediatric polyps, juvenile polyps, also classified as retention polyps, represent the most frequent subtype, typically manifesting in children between the ages of 3–10 years⁴. These lesions are primarily characterized by cystic-dilated glands and an expanded, inflammatory stroma, often resulting from localized mucosal redundancy or chronic inflammatory stimuli⁵. Although juvenile polyps are traditionally regarded as benign inflammatory hamartomas, they are associated with several critical clinical risks that cannot be overlooked⁶. Chronic blood loss from the hyperemic and fragile surface of a polyp can lead to severe iron-deficiency anemia, which may negatively impact a child’s developmental milestones and cognitive progress⁷. Furthermore, large polyps can act as lead points for intussusception or cause intermittent bowel obstruction, leading to acute abdominal emergencies that require urgent surgical intervention⁸. Although considered rare in sporadic cases, isolated reports have also documented the potential for adenomatous transformation and subsequent malignant progression in long-standing or multiple juvenile polyps, reinforcing the clinical necessity of early and complete resection⁹.

A recurring difficulty in pediatric clinical practice is the subtle and often non-specific presentation of these polyps, which leads to a significant rate of misdiagnosis¹⁰. Because pediatric hematochezia is frequently painless, it is often erroneously attributed to more common benign anal conditions such as internal hemorrhoids or anal fissures by primary care providers¹¹. This clinical misclassification frequently leads to prolonged periods of ineffective conservative management and parental anxiety¹². As demonstrated in the present case, the patient suffered from intermittent bleeding for a full year before receiving a definitive diagnosis, a delay that is unfortunately common in regions where pediatric endoscopy is not routinely prioritized¹³. Such delays significantly exacerbate the physiological burden on the child, including the risk of chronic nutritional deficiencies and persistent psychological stress for the family unit¹⁴. Recent epidemiological investigations suggest that the detected incidence of pediatric colorectal polyps is increasing globally, a trend that may be attributed to improved diagnostic accessibility, such as high-resolution endoscopy, alongside shifts in environmental factors and Westernized dietary influences¹⁵. The exact pathophysiology of pediatric polyps remains a subject of ongoing research, with current theories pointing to a complex combination of genetic predisposition and localized inflammatory responses within the colonic mucosa¹⁶.

The anatomical distribution of pediatric polyps is another critical factor that clinicians must consider during the initial diagnostic workup¹⁷. While approximately 90% of these lesions are localized in the rectosigmoid region, a significant proportion of patients harbor proximal or multiple polyps that would be missed by simple digital rectal examinations or limited sigmoidoscopy¹⁸. This distribution pattern emphasizes the necessity of performing a full colonoscopy rather than a limited examination to ensure that synchronous lesions are not overlooked¹⁹. Historically, the management of large colorectal polyps in children often necessitated open surgical intervention or transanal excision, both of which carry inherent risks of postoperative adhesions, prolonged hospitalization, and significant physical trauma to the developing child²⁰. The advent of therapeutic endoscopy has revolutionized this field, offering a safer and less invasive alternative that allows for simultaneous diagnosis and definitive treatment during a single procedure²¹. Endoscopic polypectomy, and more specifically Endoscopic Mucosal Resection (EMR), has emerged as the gold standard for managing colorectal lesions larger than 10 mm in diameter in both adult and pediatric populations²².

EMR offers several distinct technical and biomechanical advantages over traditional cold or hot snare polypectomy. By injecting a saline-based solution into the submucosal space, the clinician creates a protective fluid cushion that elevates the lesion and increases the safety margin between the mucosa and the muscularis propria. According to foundational pediatric outcome data, including the largest single-center pediatric EMR study to date, EMR is highly effective in children, achieving superior en bloc resection rates for large lesions while maintaining a low adverse event profile compared to conventional polypectomy²³. Concrete practical selection boundaries for opting for EMR over conventional snare polypectomy in children include: (1) sessile or sub-pedunculated polyps measuring 15–20 mm; (2) lesions with a broad base where single-step conventional snare capture is technically difficult or margin clearance is uncertain; and (3) polyps located in anatomically precarious regions (such as the thin-walled right colon) where the risk of thermal injury is elevated²⁴. The creation of a submucosal cushion effectively mitigates the risks of deep thermal injury and subsequent delayed perforation, which are the most feared complications of therapeutic endoscopy²⁵. Despite these clear benefits, performing EMR for large polyps exceeding 20 mm remains technically demanding in young children due to the narrow caliber of the pediatric colon and the complexities associated with providing stable general anesthesia.

Diagnostic strategies have also evolved to include non-invasive imaging modalities as essential supportive tools for preoperative planning. While colonoscopy remains the definitive gold standard, multi-modal imaging such as three-dimensional computed tomography (3D CT) and high-frequency ultrasound can provide valuable preliminary data regarding lesion size, vascularity, and exact anatomical location, especially in emergency settings to rule out other acute pathologies²⁶. While EMR is well-established for large polyps, its granular technical application in the pediatric demographic warrants further documentation. This illustrative case adds meaningfully to the existing pediatric EMR literature by detailing the specific technical nuances, equipment settings, and multi-step clinical decision-making required to safely manage a delayed-diagnosis, large rectal polyp initially presenting as an acute pediatric emergency²⁷.

Case presentation:
A 7-year-old female presented to the Emergency Department with acute lower gastrointestinal bleeding and was subsequently admitted to the Department of Gastroenterology in October 2025 with a significant one-year history of intermittent hematochezia. The symptoms initially manifested as small amounts of bright red blood streaking the end of the stool, occurring approximately once every 1–2 weeks. The bleeding was occasionally accompanied by mild anal pain. Before admission, the patient had sought medical consultation at a general surgery clinic where she was empirically diagnosed with internal hemorrhoids. Management at that time consisted of conservative dietary modifications, including increased intake of fiber and fluids to maintain soft stools; however, no formal endoscopic evaluation was performed. Despite adherence to these recommendations, the hematochezia persisted and worsened over the week leading up to admission, characterized by bright red blood dripping after defecation, prompting an immediate emergency medical evaluation. The patient also reported occasional difficulty in defecation and dry stools. There were no associated symptoms of abdominal pain, vomiting, diarrhea, dizziness, fatigue, or significant weight loss.

The patient had no notable past medical history, with a normal growth and developmental trajectory. Family history was non-contributory for gastrointestinal malignancies or hereditary polyposis syndromes. Upon physical examination, the patient was alert and hemodynamically stable. Her conjunctivae and sclerae showed no signs of anemia or jaundice. Superficial lymph nodes were not palpable. Abdominal examination revealed a soft, non-tender abdomen with no palpable masses, organomegaly, or signs of peritoneal irritation. Laboratory investigations, including a complete blood count (CBC), liver and renal function tests, electrolytes, ultra-sensitive C-reactive protein (CRP < 0.5 mg/L), procalcitonin (PCT 0.04 ng/mL), and coagulation profiles, were all within normal reference ranges. A fecal occult blood test (FOBT) was positive. Chest radiography and electrocardiography showed no clinically significant abnormalities, although a minor sinus arrhythmia and short PR interval were noted.

Diagnosis, assessment, and plan:

Diagnosis: Large rectal retention polyp (juvenile polyp) with chronic intermittent hematochezia.

Assessment: Upon admission, the clinical focus was to identify the source of the prolonged lower gastrointestinal bleeding. Given the acute exacerbation of symptoms leading up to admission, an abdominal contrast-enhanced 3D CT was strictly prioritized as an initial screening tool to rapidly rule out life-threatening acute surgical abdomens common in children, such as intussusception or bleeding from a Meckel’s diverticulum. The CT identified a nodular, high-density protrusion in the rectum measuring approximately 15 mm × 12 mm, suggesting a polypoid lesion rather than vascular congestion. Subsequent diagnostic colonoscopy was performed, revealing a large sub-pedunculated polyp on the left rectal wall, measuring 20 mm × 25 mm. The polyp exhibited a hyperemic, “strawberry-like” surface with punctate white sediment. The “hemorrhoid trap” was thus definitively ruled out. Differential diagnoses considered included inflammatory bowel disease (IBD)-associated polyps and Peutz-Jeghers syndrome; however, the solitary nature and characteristic morphology were highly suggestive of a sporadic juvenile (retention) polyp. The size of the lesion (>20 mm) presented a high risk for spontaneous torsion, ongoing hemorrhage, or neoplastic transformation, providing a clear indication for therapeutic intervention.

Plan: Following a multidisciplinary discussion and obtaining informed consent from the legal guardian, the patient was scheduled for Endoscopic Mucosal Resection (EMR). Immediate conventional snare polypectomy during the initial diagnostic colonoscopy was deemed unsafe due to the lesion’s magnitude and the unacceptably high risk of severe bleeding in a pediatric patient. Therefore, the procedure was purposefully deferred to a scheduled EMR session under deeper endotracheal general anesthesia, ensuring the availability of specialized electrosurgical and hemostatic equipment. The EMR technique was selected over simple snare polypectomy to ensure a safer, deeper resection margin and to protect the relatively thin pediatric rectal wall. The plan included submucosal injection to create a fluid cushion, followed by high-frequency snare resection. To mitigate the risk of delayed postoperative hemorrhage or perforation, mechanical closure of the mucosal defect with endoclips was planned. Postoperative management included fasting, parenteral nutritional support, and a conservative inpatient observation period to monitor for delayed complications.

Protocol

This protocol was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of the 922nd Hospital of the Joint Logistic Support Force (Approval number: 2025-12). The following steps outline the specific clinical workflow utilized for this illustrative single-case report. Procedural parameters were tailored to this patient and should be adapted based on individual patient needs, lesion characteristics, and institutional standards in general practice. The reagents and the equipment used are listed in the Table of Materials.

1. Patient selection and preoperative preparation

1. Pediatric patients presenting with chronic intermittent hematochezia for whom initial conservative management had failed, and large polypoid lesions, were selected.
2. A comprehensive physical examination and baseline laboratory testing, including a complete blood count (CBC), coagulation profile, and inflammatory markers, were performed to ensure surgical fitness.
3. A standard pediatric bowel preparation regimen was administered. Polyethylene glycol (PEG) 3350 with electrolytes was administered at a dose of 25 mL/kg/h until the rectal effluent was clear.
4. The patient remained nil per os (NPO) for at least 8 h before the procedure.

2. Preoperative imaging and diagnostic assessment

1. In emergency presentations with acute bleeding, an abdominal contrast-enhanced 3D computed tomography (CT) scan was performed to rapidly rule out life-threatening acute surgical abdomens (e.g., intussusception or Meckel’s diverticulum).
2. Endotracheal general anesthesia was administered to secure the airway and ensure pediatric patient stability during the prolonged therapeutic intervention.
3. Diagnostic colonoscopy was performed using a high-definition gastrointestinal endoscopy system (see Table of Materials) to confirm the polyp’s size, site, and sub-pedunculated morphology.
4. The mucosal surface was carefully inspected for specific morphological features, such as hyperemia or punctate white sediment.

3. Endoscopic Mucosal Resection (EMR) procedure

CAUTION: The electrosurgical grounding pad was securely attached to the patient to prevent unintended electrical burns during resection.

1. The submucosal injection solution was prepared by mixing normal saline with 1:100,000 epinephrine and 0.004% indigo carmine dye.
2. A disposable endoscopic injection needle was advanced through the working channel of the colonoscope.
3. Approximately 8 mL of the prepared solution was injected into the submucosal layer at the base of the polyp.
   NOTE: The specific volume of the submucosal injection was adjusted according to the size and morphology of this lesion to ensure an adequate lifting sign; this volume will vary significantly for other cases.
4. A positive “lifting sign” was observed to confirm that the lesion was sufficiently elevated and not tethered to the underlying muscularis propria.
   NOTE: If the lesion did not lift adequately, the EMR procedure was aborted, as this non-lifting sign suggested deep submucosal invasion or severe fibrosis.
5. A 25 mm stiff braided snare was advanced through the working channel and positioned securely around the elevated base of the polyp.
6. The snare was connected to a microprocessor-controlled electrosurgical unit.
7. The resection was performed using the Endocut Q mode. The parameters were set to Effect 3, Cut Duration 1, and Cut Interval 3 to achieve optimal simultaneous cutting and coagulation¹⁰.
   NOTE: These electrosurgical settings were specifically tailored to the generator model and the biomechanical properties of the target tissue in this case, and must be individualized in broader practice.
8. The resection wound bed was immediately inspected for any signs of active bleeding or muscular injury.
9. Mechanical endoclips were deployed across the mucosal defect to achieve complete prophylactic closure and mitigate the risk of delayed hemorrhage.

4. Specimen handling and pathological diagnosis

1. The resected specimen was safely retrieved using an endoscopic retrieval net to prevent loss or fragmentation in the colonic lumen.
2. Immediately after retrieval, the specimen was oriented and pinned on a corkboard to prevent tissue curling and ensure accurate margin assessment.
3. The fixed specimen was completely submerged in 10% neutral buffered formalin solution.
4. The specimen was transported to the pathology department.
5. The tissue was processed for standard Hematoxylin and Eosin (HE) staining, and histopathological evaluation was performed at low-power (4x) and high-power (10x) magnification to confirm the presence of cystic-dilated glands and an expanded inflammatory stroma.

5. Postoperative management and follow-up

1. The patient was kept nil per os (NPO) for 24 h post-procedure.
2. Intravenous supportive therapy, including 5% glucose and pediatric-specific 18AA-I amino acids, was provided during the fasting period.
3. Oral probiotics (e.g., Bacillus licheniformis) were administered once oral intake resumed to regulate intestinal microflora.
4. The patient was closely monitored in an inpatient setting for abdominal pain, vital sign instability, or recurrent bleeding. Observation was maintained to cover the peak risk period for delayed post-EMR hemorrhage (days 3 to 7).
5. The patient was discharged upon complete resolution of symptoms and confirmation of stable clinical status.

Results

The EMR procedure was executed successfully in 9 min, without any perioperative or immediate postoperative complications. The estimated immediate intraoperative blood loss was minimal, ranging from 1–2 mL. Initial endoscopic inspection via the video colonoscope identified a large, sub-pedunculated polyp measuring 20 mm × 25 mm on the left rectal wall, approximately 5 cm from the anal verge. The polyp exhibited a hyperemic, ‘strawberry-like’ appearance with distinct punctate white sediment on its surface (

Discussion

The clinical management of pediatric hematochezia remains a significant challenge in gastroenterology due to the overlap of symptoms between benign anal conditions and more serious intra-luminal pathologies¹. The present case of a 7-year-old girl with a large rectal retention polyp illustrates a classic diagnostic dilemma frequently referred to as the “hemorrhoid trap” in pediatric practice¹⁰. Because pediatric colorectal polyps typically present with painless b...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Bacillus licheniformis Capsules	Northeast Pharmaceutical	N/A
Disposable Endoscopic Injection Needle	Boston Scientific	M00516150
Electrosurgical Unit	Erbe Elektromedizin	VIO 300 D
Epinephrine Injection (1 mg/mL)	Pfizer	0069-3041-01
Hematoxylin and Eosin (HE) Stain Kit	Sigma-Aldrich	HT110116
Hemostatic Clips (Rotatable)	Micro-Tech (Nanjing)	ROCC-F-26-195-C
High-frequency Snare (25 mm, stiff braided)	Cook Medical	M00562100
Indigo Carmine (0.8% for injection)	Akorn	17478-501-02
Neutral Buffered Formalin (10%)	Sigma-Aldrich	HT501128
Normal Saline (0.9% NaCl)	Baxter	2B1324
Pediatric Amino Acid Injection (18AA-I)	Baxter	N/A
Polyethylene Glycol (PEG) 3350	Braintree Laboratories	52268-0100-01
Propofol (1% Injection)	AstraZeneca	N/A
Specimen Retrieval Net (Roth Net)	US Endoscopy (Steris)	711105
Video Colonoscope System	Olympus	CF-HQ190L