Polyps are the most common causes of colorectal bleeding in children [1,2]. Polyps occur in as many as 1% of children and 90% of these are juvenile polyps [1]. The intermittent indolent rectal bleeding is the main symptom of colonic polyps. Juvenile polyps are generally thought to be hamartomatous lesion with little malignant potential. They have been reported to be solitary and rectosigmoid in location in 80-90% of cases [3,4]. However, some of recent studies demonstrated that a significant number of cases of polyps are multiple and proximally located, which suggests the need for total colonoscopy [2,5].

It is difficult to differentiate the hyperplastic polyps and adenomatous ones without histological examinations. Moreover, repetitive bleeding may lead to iron deficiency anemia. Therefore, early detection and polypectomy are necessary for all colonic polyps [6,7]. Fiberoptic colonoscopy is a routine modality for the diagnosis and treatment of colorectal polyps in pediatric patients [8].

Although there have been clinical studies on colonic polyps in children in Korea [9-12], the detail technical descriptions and studies using a large number of patients were far from being sufficient despite recent widespread use of colonoscopy. We, therefore, examined the clinical characteristics of juvenile polyps in children presented at a single institution and studied the effectiveness and complications of colonoscopic polypectomy.

Fifty six (67.5%) of the patients were males and 27 (32.5%) were females, the male/female ratio being 2.1 : 1. The mean age of the patients at the time of diagnosis was 6.5±3.7 (range 1.3-14.5) years.

Of the total 83 patients, eighty one (97.6%) experienced hematochezia, the most frequent being red or dark red hematochezia in 60 patients (74.1%) followed by blood on the used toilet paper after defecation in 11 patients (13.6%), dripping of fresh blood in 6 (7.4%) patients and bloody toilet water after defecation in 4 patients (4.9%) (Table 1).

The mean time interval between the first episode of hematochezia and colonoscopy was 8.9±20.4 (range 0.1-48.0) months.

The most proximal regions of colonoscopic reach were terminal ileum in 80 patients (96.4%), cecum in 3 patients (3.6%).

Sixty three patients (75.9%) had a solitary polyp and 20 patients (24.1%) had multiple polyps. Two polyps was found in 11 patients (13.3%), three polyps in 4 patients (4.8%), four polyps in 3 patients (3.6%) and five polyps in 2 patients (2.4%), totaling 119 polyps in 83 patients.

Of all polyps found, seventy three (61.4%), the largest number of all, were located in rectum. Twenty eight (23.5%) were in sigmoid colon, 8 (6.7%) in descending colon, 1 (0.8%) in splenic flexure, 3 (2.5%) in transverse colon and 6 (5.1%) in ascending colon and cecum (Table 2). Most of multiple polyps (60.0%) were found in rectosigmoid colon.

The size of the polyps varied in the range between 0.3 and 5 cm. Fifty eight (48.7%), the largest number, had diameter between 1-1.9 cm, forty six (38.7%) were less than 1 cm, 13 (10.9%) were between 2.0-2.9 cm, and 2 (3.1%) were larger than 3 cm (Table 3).

All polyps in the study were excised using the loop snare technique. Pre-operative submucosal saline-epinephrine injection was used in 19 patients (22.9%). Hemostasis clip was used pre-operatively in 1 patient (1.2%) and post-operatively in 39 patients (47.0%). Retroflexion endoscopic polypectomy was performed on 6 patients (7.2%) and detachable loop snare was used on 1 patient (1.2%) pre-operatively.

Hematochezia recurred after polypectomy in 9 patients (10.8%). Among them, 8 patients underwent a repeat colonoscopic examination. Hemostasis clip was used on 2 patients due to severe hemorrhage. All patients undertook colonoscopy under sedation without complications. No operation-related complication was reported except for hemorrhage.

Until the colonoscopy became a common practice with children, it was believed that most of detected juvenile polyps are solitary polyps with 90% of them occurring in proctosigmoid [13]. However, according to a report by Mestre [14], 50% of juvenile polyp patients had multiple polyps of which 60% were found more proximal locations than proctosigmoid. Other foreign studies reported that 24-58% of patients had more than one polyp and 15-60% of polyps were found at the locations more proximal than proctosigmoid [4,6]. Seo [9] reported that 67% of polyps were found in proctosigmoid, while Cheon et al. [10] reported that all observed cases had a solitary polyp of which 79% were found in proctosigmoid. Kim et al. [11] also reported that 94.4% of observed polyps were found in proctosigmoid. However, total colonoscopy was performed in 28% of the cases, the possibility of the existence of more polyps could not excluded in this study.

In our study, although 84.9% of polyps were found in rectosigmoid colon, eighteen polyps (15.1%) were found more proximal locations than rectosigmoid. Multiple polyps were found in 24.1% of patients and the number of polyps ranged from 2 to 5. Most of multiple polyps (60.0%) were also found in rectosigmoid colon. Size of the polyps was, in most cases, 1.0-1.9 cm in diameter. Large polyps larger than 3 cm were found in only 1.7% of patients, coinciding with the observations by other studies [9-11].

All patients underwent total colonoscopy, therefore, multiple polyps could be detected in many patients and polyps could be found in more varied locations. Moreover, the authors could not find out the clinical predicting factors associated with multiple polyps and more proximally located polyps. This emphasizes the necessity for total colonoscopy on all juvenile polyp patients because sigmoidoscopy can result in a failure of detecting polyps.

Juvenile polyp is common in children of age between 2 and 10 years and the mean age at the time of diagnosis is known to be 5-7.4 years [4,6,14-16]. It is rare in children of age under 1 year and over 15 years [17]. In our study, the mean age of the patients was 6 years and there were no children under 1 year old or over 15 years old.

The juvenile polyps have been reported to be more common among males [4]. However, Cynamon et al. [6] reported the same prevalence rate in both genders and Bartnik et al. [17] even reported higher prevalence in females. In Korea, Kim et al. [11] reported higher prevalence in males and Cheon et al. [10] reported similar rates in males and females. In this study, the prevalence ratio between males and females was 2.1 : 1 coinciding with the generally known trend [18].

The most common symptom of juvenile polyp is intermittent mild hematochezia without accompanying abdominal pain, which appeared in 90% of the cases. Seo [9] reported symptoms comprising; stool with fresh blood in 89% of patients, abdominal pain in 50%, diarrhea or mucous stool in 45%, anemia in 29% and constipation in 16%. While Cheon et al. [10] reported rectal bleeding in 100% of patients comprising stool with fresh blood in 84% of patients, blood on used toilet paper in 53% and dark brown or black stool in 16%, with accompanying symptoms of diarrhea in 42% of patients, abdominal pain in 26%, constipation in 11% and anal fissure in 11%. In our study also, almost all patients (97.6%) had hematochezia with blood mixed with stool rather than blood dripping down to the toilet water found in a largest number of patients (74.1%), indicating more patients experienced relatively small amount of bleeding.

The mean duration of symptom in previous reports was 12-16 months [6]. Studies in Korea reported the mean duration being 7.6 months [10] and 5 months [11] indicating that diagnosis was usually delayed because many patients did not seek treatment early enough since most of them had only small amounts of bloody stool without accompanying abdominal pain.

The solitary juvenile polyp that appears in most of children is a hyperplastic polyp that is less likely to develop to malignant tumor. However, multiple juvenile polyps are know to have higher risk of adenomatous change to a cancer precursor [4,16,19]. Since cancerous changes were observed in 5% of solitary polyp cases as reported by Poddar et al. [4] and repetitive bleeding may lead to iron deficiency anemia, all polyps may require early detection and excision [6,7].

Juvenile polyps can be excised easily using a loop snare because most of them are pedunculated polyps. However, for those with short or thick necks or sessile typed polyps, use of pre-operative submucosal saline-epinephrine injection [20], hemostasis clip [21] or detachable snare [22,23] will be effective for the prevention of hemorrhage during excision. Loop snare technique was used in all cases in our study with pre-operative submucosal saline-epinephrine injection given to 22.9% of patients, hemostasis clip used pre-operatively in 1.2% of patients and post-operatively in 47.0% of patients. Detachable snare was used in 1.2% of patients. Retroflexion endoscopic polypectomy was performed on 7.2% of patients because of location of the polyp close to the anal margin and inability of direct approach.

No cases of complications caused by the use of drugs for sedation have been reported in Korea [9-11]. Also in this study, all patients underwent colonoscopy and colonoscopic polypectomy under sedation without any complications.

Possible complications of polypectomy include hemorrhage and intestinal perforation. Intestinal perforation were not occurred in this study. However, hematochezia recurred in 9 patients and repeat colonoscopy was performed on 8 patients of whom 2 patients had severe hemorrhage at the sites of polypectomy and hemostasis clips had to be used. Hemorrhage in other patients stopped spontaneously after conservative treatments. The authors did not revealed the causes of rebleeding after polypectomy in this study. In a study with adult patients, size and numbers of polyps, and skill level of procedure were independent risk factors for delayed bleeding after polypectomy [24].

Since the recurrence rate of solitary juvenile polyp is very low at 4.5% according to Poddar et al. [4], follow-up colonoscopy is not recommended except in the case of recurrence. However, recurrence rate of polyps is 17-37.5% with highest risk in patients with more than five polyps, follow-up colonoscopic examination must be performed every 2-3 years [4]. Since the possibility of the existence of juvenile polyposis coli cannot be ruled out in such patients, the first diagnostic colonoscopy must be performed on the entire colon in patients suspected with polyps.

In conclusion, juvenile polyp occurs in a wide range locations and had variable sizes and numbers, suggesting that colonoscopy on the entire colon is necessary in patients with painless intermittent hematochezia. Colonoscopic polypectomy is a simple, safe and effective therapeutic method in children.