after the first report by diamond   in 1939 , juvenile polyps , one of the polyps found in the large intestine , have been reported to occur in relatively young people .
the juvenile polyp is a type of harmatoma that develops in the connective tissue of the large intestinal submucosal layer , but its etiology is not clear . in a recent study ,
multiple juvenile polyposis was reported to have a cumulative malignant potential in 50% of the patients .
on the other hand , a solitary lesion is thought to a benign disease with low malignant potential , and it can be treated sufficiently by using only an endoscopic polypectomy , with no follow - up observation being required . in a patient admitted for the chief complaint of anal bleeding , we detected polyps in the sigmoid colon and performed an endoscopic polypectomy . by histopathologic test , the polyp was diagnosed as a harmatoma with a focal signet ring cell carcinoma limited to the mucosal layer .
this case is reported as a rare case of malignant degeneration of a solitary juvenile polyp .
a 21-year - old female visited our hospital with a chief complaint of bleeding on defecation . in digital rectal examination , no hemorrhoid , anal fissure or other anal disease
was found , but blood - tinged stool was detected . for several days , she had had symptoms of diarrhea , with no abdominal pain or febrile sense .
none of her family had had inflammatory bowel diseases , multiple polyposis , malignant diseases in the digestive tract , except that her mother had undergone breast cancer surgery .
the polyp had two branching heads , 20 mm and 27 mm in size respectively , and the surface was relatively smooth , but covered with mucous discharge .
in addition , a lobulating change , different from that in typical juvenile polyps , was found ( fig .
after a detached snare had been applied , a snare polypectomy was done in the neck of the polyp . during the polypectomy , no hemorrhage or abdominal pain developed , and
on pathologic examination , the polyp was diagnosed as a juvenile polyp that had several branches , multiple cystic changes , and interstitial edema with mucinous congestion and infiltration of acute and chronic inflammatory cells ( fig .
2 ) . in some areas of the polyp , local infiltration of a signet ring cell carcinoma into the mucosa was observed , but there was no adenomatous change ( fig .
performed after the polypectomy , no distant metastasis or infiltration to adjacent tissues was detected , and serum level of carcinoembryonic antigen or ca19 - 9 was not elevated . in the follow - up endoscopic examination performed 3 months later , no recurrence at the polypectomy site or residual polyps were found ; the patient is still under outpatient follow - up observation .
horrilleno et al .   termed pediatric polyps showing the formation of cysts by the epithelial grands with abundant mucoid , increased connective tissues , and chronic infiltration of eosinophils as juvenile polyposis , and morson   referred to such polyps showing hyperproliferation of normal tissues in the upper part of interstitial tissue as a harmatoma .
afterward , mccoll et al .   reported multiple juvenile polyposis , which was considered to be a different disease from multiple adenomatosis .
the most frequent symptom of juvenile polyposis is hemorrhage in the rectum , as shown in our case ; anal prolapse , abdominal pain , diarrhea , mucous stool , rectal prolapse , and other symptoms may also develop . in approximately 10% of the patients ,
juvenile polyposis in the large intestine is detected in the distal rectum in most cases .
typical juvenile polyps have a round or an oval pedunculated form with a smooth continuous surface , and numerous microcysts filled with mucoid are detected in a cross section .
in addition , in 20% of the cases , multicentric segments or branches are observed . in microscopic findings in the upper part of the mucularis mucosa , glandular
epithelial ducts with columnar epithelial cells and goblet cells are found , and they show cystic dilatation and are filled with mucin and numorous inflammatory cells .
these are benign lesions if cellular hyperproliferation , hypercchromatism , and excessive cell division of the epithelial cells covering the surface are not present , and they can be sufficiently treated by using only a colonoscopic polypectomy .
since the malignant deterioration potential is very low , follow - up observation is not required .
when such juvenile polyposis occurs in a familial form , it is inherited as an autosomal dominant trait .
approximately 25 - 50% of the cases are associated with adenoma or dysplasia with a malignant potential ; thus , they are considered as precancerous lesions .
in addition , in multiple polyposis , besides the large intestine , polyps may develop in the entire digestive system in some cases ; thus , if a family history is suspected or genetic mutation is confirmed , for the assessment of multiple lesions , an overall examination of the esophagus , stomach , small intestine and large intestine is required .
the cause of the development of cancer in juvenile polyposis has not been elucidated yet . the surface ulcer observed in some polyps , infection and necrosis
according to jass et al . , the malignant potential of a solitary juvenile polyp is very low .
nonetheless , jones et al .   reported adenomatous changes and cases of signet ring cell carcinoma limited to the mucosal layer , but in our case , adenomatous changes were not found .
the mechanism of malignant deterioration or carcinomatous changes in solitary polyps is thought not to be different from the mechanism in juvenile polyposis .
although it is very rare , the possibility of malignant deterioration of solitary juvenile polyposis should be kept in mind , and in a polypectomy , attention should be paid to securing sufficient resection margins .
 juvenile polyps are relatively common polyps that affect predominantly young patients and may occur in isolated , multiple , and/or familial forms . they have been considered to be benign lesions without neoplastic potential , but for patients with multiple juvenile polyposis , the cumulative malignant risk is greater than fifty percents . in patients with a solitary polyp , 
 the risks are minimal , and only a few cases of malignant change from a solitary juvenile polyp have been reported . 
 we describe the case of a twenty one year old female with one solitary juvenile polyp , which contained a signet ring cell carcinoma in the mucosal layer . 
INTRODUCTION
CASE REPORT
DISCUSSION