Two cases of inverted hyperplastic polyps of the colon and association with adenoma

Here we report two cases of inverted hyperplastic polyps of the colon. The first patient showed three inverted hyperplastic polyps in the ascending colon, one of which was associated with adenoma. We immunostained this adenoma-associated polyp using anti-beta-catenin antibody and found accumulation of beta-catenin in the cytoplasm of the adenomatous lesion but not in the inverted hyperplastic polyp. This suggested an adenomatous polyposis coli (APC) mutation in the adenomatous region but not in the inverted hyperplastic polyp. The inverted hyperplastic polyp in the second patient was located at the caecum and was studied using magnifying colonoscopy. The polyp appeared to be flat and elevated with a depressed pit in the centre. After spraying with methylene blue dye, the pit pattern of the lesion was observed and small asteroid pits on the polyp were found, consistent with a hyperplastic gland pattern. From these results, we diagnosed inverted hyperplastic polyp of the colon by colonoscopy.     

Early sigmoid colon carcinoma developed from a pedunculated polyp

A 60‐year‐old man underwent routine colonoscopy, and was noted to have a pedunculated polyp in the sigmoid colon. The pathologic diagnosis was adenoma, and due to patient’s personal circumstances, the lesion was left untreated. The colonoscopic examination was repeated 4 years and 11 months later, to find that the polyp had transformed into an elevated lesion with irregularly depressed surface. The patient was diagnosed as having early sigmoid cancer, and underwent sigmoidectomy. The histologic examination of the excised specimen revealed well‐differentiated adenocarcinoma with invasion into the submucosal layer. Through studying the natural course of colon cancer, it has become known that the advanced cancers commonly develop from polyps with short pedicles (sessile polyps). This case represents an early sigmoid cancer developed from a pedunculated polyp, which differs from the current mainstream concept of ‘polyp‐cancer sequence of colon cancer.’     

POLYPOID COLONIC HAMARTOMATOUS INVERTED POLYP

We herein present a unique polyp diagnosed as polypoid colonic hamartomatous inverted polyp. Colonoscopic examination revealed a clover‐like submucosal tumor about 30 mm in size with a long stalk at the mid‐transverse colon. The polyp consisted of elongated crypts with cystic dilatation located in the submucosal layer. To the best of our knowledge, there have been no previous reports of the same type of pedunculated colonic polyp, similar in appearance to inflammatory myoglandular polyps but covered with a layer of normal mucosa possessing the muscularis mucosae at the uppermost surface of the polyp.     

Adenocarcinoma in solitary large hyperplastic polyp diagnosed by magnifying colonoscope: report of a case

We report a case of carcinoma in a hyperplastic polyp in a 78-year-old female that was diagnosed before resection using a magnifying colonoscope. The patient presented with fecal occult blood and underwent total colonoscopy, which revealed a 12-mm sessile polyp in the cecum. When seen in magnified view, an irregularly shaped pit was evident at the center of the polyp that was distinct from the asteroid-type pits observed over most of the lesion. We diagnosed this lesion as a hyperplastic polyp with a carcinoma component. The patient underwent endoscopic mucosal resection, and histologic section revealed a well-differentiated intramucosal adenocarcinoma in the hyperplastic polyp. Hyperplastic polyps of the colon are regarded as benign, nonneoplastic lesions. Few have reported carcinomas in or with hyperplastic polyps, and most of those were diagnosed after resection and histologic investigation. The literature suggests a precise observation and consideration of resection for large solitary hyperplastic polyps in the right side of the colon, because the risk of malignancy is high. Magnifying colonoscopy is helpful for observing the surface in detail and for correctly diagnosing and managing the lesion.     

Fibrovascular polyp of the sigmoid colon

A case of a fibrovascular polyp of the sigmoid colon is reported. The patient tested positively for fecal occult blood on a mass survey for colorectal cancer, and underwent colonoscopic examination which revealed a pedunculated submucosal tumor in the sigmoid colon. The tumor, about 10 mm in diameter, had a short thin stalk and was removed endoscopically; the histological diagnosis was fibrovascular polyp. This extremely rare polyp is discussed, and particular attention is focused on the unusual endoscopic features and on the appropriate management.     

Hyperplastic Colonic Polyps as a Marker for Adenomatous Colonic Polyps

Hyperplastic colonic polyps are generally regarded as being of little or no clinical consequence. Recently, however, hyperplastic polyps have been found to share numerous functional similarities with colorectal carcinoma. To determine whether the presence of an isolated left-sided colonic hyperplastic (metaplastic) polyp could serve as a marker for more proximal synchronous adenomatous colonic polyps, we retrospectively analyzed all consecutive colonoscopic polypectomies performed over an 18-month period at two medical centers. It is the policy at both institutions to remove or biopsy all polyps, regardless of size. Indications for colonoscopy included known or previous colonic polyps or carcinoma, hemoccult positive stool, lower gastrointestinal bleeding, iron deficiency anemia, abnormal barium enema, inflammatory bowel disease, abdominal pain, and family history of colon cancer. The location of adenomatous polyps and hyperplastic polyps was recorded and compared. One hundred sixty-three of 845 consecutive patients (19.3%) had at least one colonic polyp. The prevalence of adenomatous polyps alone was 10.3%, hyperplastic polyps 9%, and both types 1.9%. The prevalence rate for an adenomatous polyp in patients without a hyperplastic polyp was 15%. In contrast, among patients with a hyperplastic polyp, 49% had a synchronous adenomatous polyp. Only 3.4% of patients had an adenomatous polyp proximal to the splenic flexure when no polyps were present in the left colon. Conversely, among the 29 patients in whom an isolated hyperplastic polyp was found in the left colon, there was a 32.5% prevalence of adenomatous polyps in the proximal colon (p less than 0.01). The results of this study suggest that left-sided hyperplastic colonic polyps (generally within the reach of a screening sigmoidoscopy) serve as a marker for neoplastic polyps.     

Lobulated inflammatory myoglandular polyp in the ascending colon observed by magnifying endoscopy and treated with endoscopic polypectomy

The patient was a 33-year-old man with hematochezia. Colonoscopy revealed a Iobulated peduncular polyp with bleeding, about 40 mm in diameter, in the ascending colon. The polyp had both red and white components and a mosaic pattern. Magnifying observation revealed a red rugged surface component, and smooth white nodules with enlarged round or oval crypt openings. Endoscopic polypectomy was performed. Histological examination of the specimen revealed inflammatory granulation tissue in the lamina propria, proliferation of smooth muscle, and hyperplastic glands with cystic change. This polyp was diagnosed as inflammatory myoglandular polyp （IMGP）. Lobulated-type IMGP in the ascending colon is rare.     

Spatial clustering of multiple hyperplastic,adenomatous, and malignant colonic polyps in individual patients

Analysis of relative polyp locations in 426 consecutive patients with multiple colonic polyps found on colonoscopy showed novel findings. First, synchronous and metachronous neoplastic polyps showed spatial clustering in individual patients. For example, patients with their largest neoplasm in the cecum or proximal ascending colon, had 34.3 percent±4.6 percent (standard error) of their other colonic neoplasms in the same location. Second, hyperplastic polyps showed spatial clustering in individuals that was statistically significantly greater than expected from the increased hyperplastic polyp concentration in the rectum and sigmoid. Third, hyperplastic polyps showed spatial clustering with neoplastic polyps; this clustering was similar in magnitude to clustering for exclusively hyperplastic or neoplastic polyps. In contrast, lipomas were not spatially clustered with hyperplastic and neoplastic polyps. The magnitude of clustering between hyperplas and neoplasia showed a closer association between these histologic types than previously appreciated. Because of clustering, regions with prior polyps appear to merit closer surveillance. These findings suggest clinical study, using a randomized controlled clinical trial, of whether a patient who had only rectal and sigmoid adenomas on initial and follow-up colonoscopy should have surveillance with flexible sigmoidoscopy alternating annually with colonoscopy. A patient with a prior cecal adenoma should have surveillance only with a complete colonoscopy or adequate cecal views on barium enema.     

Acromegaly and colon cancer

The occurrence of colon cancer in 1 patient with acromegaly prompted a study of an additional 12 patients with acromegaly. In addition to the index case, 1 patient was retrospectively discovered to have colon cancer, and 1 was found to have colonic adenocarcinoma in the course of the study. One patient had a presumptive sigmoid polyp shown by barium enema but refused further studies. Eight patients received colonoscopy. Two patients had adenomatous polyps and 1 had two hyperplastic polyps. This study supports previously published data on the occurrence of colon polyps in patients with acromegaly and suggests that the incidence of colon cancer is much higher than that expected by chance.     

Solitary juvenile polyp developing adenocarcinoma with submucosal invasion

Solitary juvenile polyps are generally non‐neoplastic hamartomatous polyps. Inflammation is suggested as the cause of proliferation and progression of these polyps, and adenomatous and carcinomatous changes are rare. We report a rare case of a solitary juvenile polyp with malignant transformation that developed in the sigmoid colon of a 12‐year‐old boy. A 3 cm, pedunculated polyp was endoscopically resected, and histologic evaluation revealed the characteristic features of a juvenile polyp. However, mucous‐filled ectatic glandular spaces were lined by mucin‐secreting columnar epithelial cells with atypical change, and an admixture of adenocarcinoma invading the submucosa was confirmed. The histologic features may suggest the involvement of the adenoma–carcinoma sequence in the development of adenocarcinoma in the present case. Although rare, solitary juvenile polyps should develop adenocarcinoma and thorough histologic evaluation of the resected polyps is warranted to identify the adenomatous tissue.     

Multiple Large Hyperplastic Polyps of the Colon Coincident with Adenocarcinoma

Diminutive hyperplastic polyps are the most common non-neoplastic lesions of the colon. Typically, they are small (<0.5 cm) sessile lesions, lack cellular atypia, and are found predominantly in the rectosigmoid region of the colon. Multiple large hyperplastic polyps (>1 cm) are rare. Although the relationship between diminutive hyperplastic polyps and adenomatous polyps or carcinoma is controversial, even less data are available on the significance of large hyperplastic polyps. We report the case of a 56-yr-old man who was seen because of fatigue, anemia, and Hemoccult-positive stool. On air contrast barium enema study and colonoscopy, multiple polyps that were similar in appearance were found distributed symmetrically throughout the colon. However, histologic examination revealed 16 hyperplastic polyps 1–2 cm in size, multiple diminutive hyperplastic polyps, one adenomatous polyp, and one adenomatous polyp containing well-differentiated adenocarcinoma. Because multiple large hyperplastic polyps are rare, we suspect this entity may be distinct from diminutive hyperplastic polyps. In our patient, large hyperplastic polyps were distributed symmetrically throughout the colon and were associated with a synchronous carcinoma. Because large hyperplastic polyps may be coincident with adenomatous polyps and carcinoma of the colon, we recommend that patients found to have large hyperplastic polyps undergo removal of all polyps for histologic study.     

Inflammatory myoglandular polyp causing hematochezia

A case of inflammatory myoglandular polyp （IMGP） causing hematochezia is reported. The patient was a 33-year-old man who visited our hospital for further evaluation of hematochezia. Colonoscopy revealed a red, hard, spherical peduncular polyp with erosion and mucous exudation, about 20 mm in diameter, in the descending colon. Excluding the polyp, there was no lesion in the colorectum. Endoscopic polypectomy was performed. Histological examination of the specimen revealed inflammatory granulation tissue in the lamina propria, proliferation of smooth muscle, and hyperplastic glands with variable cystic changes. This polyp was diagnosed as an IMGP. The symptom of hematochezia was resolved after endoscopic resection. Our case shows that treatment is necessary for IMGP if intestinal bleeding occurs and endoscopists should be aware of the endoscopic characteristics of IMGP.     

Epidemiology of polyps in the rectum and colon. Recovery and evaluation of unresected polyps 2 years after detection

In an endoscopic population screening study for colorectal polyps among 200 men and 200 women, 50-59 years of age, 215 polyps less than 5 mm in diameter were left in situ for the present 2-year follow-up examination. The attendance rate was 102 of 106 (96%) for polyp patients and 77 of 90 (86%) in the control group. Of 194 polyps, 143 (74%) in the 102 polyp-bearing individuals were recovered for histological evaluation and 57 polyps were registered as new. Ninety-nine (50%) of the polyps were hyperplastic, 45 (23%) were adenomas, and 45 (23%) were mucosal tags. Both growth and regression of polyps were registered. Regression was commoner in the distal part of the rectum than in the proximal part or distal sigmoid colon. Growth was similar for recovered adenomas and hyperplastic polyps, whereas mucosal tags more often showed diminution in size. No polyp had reached a size of more than 5 mm in 2 years, and no case of severe dysplasia or carcinoma was registered. The estimated total polyp mass more than doubled both for adenomas and hyperplastic polyps. It is concluded that the time interval between initial examination with removal of polyps 5 mm or larger in diameter and the first follow-up examination may safely be set at 2 years.     

A case of pedunculated colonic adenoma with pseudocarcinomatous invasion and squamous metaplasia occurring in the sigmoid colon

A case of pedunculated colonic adenoma with pseudocarcinomatous invasion and squamous metaplasia occurring in the sigmoid colon is reported. The patient was a 65-year-old man who visited our hospital for further evaluation of a positive fecal occult blood test. Colonoscopy revealed a pedunculated polyp with a thick swollen stalk in the sigmoid colon. EUS revealed a hyperechoic lesion in the stalk. However, endosonographically, the third and fourth layers of the colonic wall were shown to be normal. It was suspected to be a colonic adenoma with pseudocarcinomatous invasion from these endoscopic findings. Endoscopic polypectomy was performed. Histological examination of the specimen revealed tubular adenoma with moderate epithelial atypia and submucosal displacement of adenomatous glands with variable cystic changes. Squamous metaplasia and hemosiderin deposition were also seen in the mucosal and submucosal layer, respectively. This polyp was diagnosed as a colonic adenoma with pseudocarcinomatous invasion with squamous metaplasia.     

A case of polypoid cavernous hemangioma of the sigmoid colon excised by colonoscopic polypectomy

A 28-year-old Japanese man was admitted to our institute because of sharp anal pain and a mass that prolapsed from the anus after defecation. After spinal anesthesia for emergency operation, the mass spontaneously withdrew into the anus and the pain disappeared. Surgery was postponed. Barium enema and colonoscopy revealed a pedunculated polyp in the sigmoid colon, which was removed by snare polypectomy with electrocautery. The resected polyp was granular and reddish, and measured 33 × 22 × 14 mm. Histological examination of the polyp revealed a cavernous hemangioma. Hemangioma of the colon is rare; only 52 cases have been reported in Japan. Of these patients, eight underwent endoscopie polypectomy. The present lesion is the largest thus treated that has been documented. Endoscopie polypectomy seems to be a safe and preferable procedure for the diagnosis and treatment of small, solitary polypoid hemangiomas of the colon.     

Prevalence of advanced colonic polyps in asymptomatic Chinese

AIM: To investigate the prevalence of advanced polyps in asymptomatic Chinese and to determine the risk of proximal advanced colonic polyps in subjects with and without polyps in the distal colon. METHODS: Data were collected prospectively during colonoscopic examinations performed in 5 973 subjects as part of health evaluation at our unit from December 1997 to December 2003. Polyps were considered advanced, if they were larger than 10 mm or were tubovillous, villous or malignant. Proximal colon was defined as the splenic flexure and more proximal portions of the colon. RESULTS: Colon polyps were detected in 971 (16.3%) subjects (613 males and 358 females) with their mean age being 56.6±10.7 years. Advanced polyps were noted in 199 (3.3%) individuals. Subjects were sub-classified according to the location of polyps into three groups: distal (569, 58.6%), proximal (284, 29.2%), and combined proximal and distal (118, 12.2%) groups. Subjects with advanced polyps in these three groups were 95 (9.8%), 56 (5.8%), and 48 (4.9%) respectively. In the 48 subjects with advanced combined polyps, 13 advanced polyps were distributed at the distal colon, 17 at the proximal colon, and 18 at both. Eighteen colon cancers including 12 at sigmoid and 6 at ascending colon were confirmed by final pathology. The relative risk for advanced proximal polyp according to distal findings was 3.1 (95%CI: 1.3-7.4) for hyperplastic polyp, 2.7 (95%CI: 1.4-5.3) for tubular polyp and 13.5 (95%CI: 5.1-35.4) for advanced polyp as compared to that for no polyp. However, 56 (28.2%) of 199 subjects with advanced polyps had no index polyps at the distal colon and might go undetected under sigmoidoscopic screening. CONCLUSION: Although distal lesions can predict the risk of advanced proximal polyps, a substantial portion of Chinese with advanced proximal polyps is not associated with any distal sentinel lesions. These data have implications for screening policy of colon cancers in Taiwanese Chinese.     

Clinical significance of diminutive polyps of the rectum and sigmoid colon

A retrospective review of 637 consecutive colonoscopies with polypectomy in 526 patients was performed to determine the association of small polyps of the rectum and sigmoid colon with more proximal colonic neoplasms. All colonic polyps were proximal to the sigmoid colon in 117 procedures. Proximal neoplasms were found in 32 percent of patients with a single polyp in the rectum or sigmoid colon. The incidence increased to 83 percent for those with three or more polyps. The occurrence of proximal colonic neoplasms was not affected by the size or histologic type of the rectosigmoid polyps. These findings would suggest that total colonic evaluation be considered in all patients with a polyp in the rectum or sigmoid colon regardless of the size or histologic type of the polyp.     

LARGE HYPERPLASTIC POLYP DEVELOPING AFTER ENDOSCOPIC MUCOSAL RESECTION OF GASTRIC ADENOMA IN A PATIENT RECEIVING IMMUNOSUPPRESSIVE THERAPY

A 59‐year‐old man underwent endoscopic mucosal resection (EMR) for gastric adenoma. He had suffered from end‐stage renal disease for several years and had received renal transplantation some 5 months before EMR. Subsequently, he took immunosuppressive agents. Follow‐up gastrofiberscopy 6 months after EMR showed a sessile polyp at the resection site twice as large as the original adenoma; biopsy specimens revealed a hyperplastic nature. At the time of writing, this hyperplastic polyp has neither increased in size nor developed adenomatous or carcinomatous changes by histological examinations over the past 5 years. Therefore, this is a case of hyperplastic polyp occurring at the gastric adenoma resection site, and suggests the possible effect of immunosuppressive therapy on the post‐EMR healing process and hyperplastic polyp development.     

A case of gastric hyperplastic polyp with malignant transformation

In this paper we report a case of hyperplastic polyp with malignant transformation. The patient was followed up by annual radiographic and endoscopic examination during 9 years. The first gastroscopy revealed a semi-pedunculated polyp beneath the esophageal-cardiac junction, 1.5cm in diameter and slightly reddish with smooth surface. Histological findings showed a hyperplastic polyp. There was slight change in size, but no change in histological examination of the lesion during the follow-up. In 1996, the biopsy specimen showed an atypical epithelium and the polyp was removed by snear polypectomy. A microscopic examination revealed a well-differentiated adenocarcinoma. Immunohistochemically, p53 and Ki-67 immunostaining showed positive in the carcinoma portion of the adenocarcinoma bearing a hyperplastic polyp in the stomach.     

Prevalence of advanced colonic polyps in asymptomatic Chinese

AIM: To investigate the prevalence of advanced polyps in asymptomatic Chinese and to determine the risk of proximal advanced colonic polyps in subjects with and without polyps in the distal colon.METHODS: Data were collected prospectively during colonoscopic examinations performed in 5 973 subjects as part of health evaluation at our unit from December 1997 to December 2003. Polyps were considered advanced, if they were larger than 10 mm or were tubovillous, villous or malignant. Proximal colon was defined as the splenic flexure and more proximal portions of the colon.RESULTS: Colon polyps were detected in 971 (16.3%)subjects (613 males and 358 females) with their mean age being 56.6±10.7 years. Advanced polyps were noted in 199 (3.3%) individuals. Subjects were sub-classified according to the location of polyps into three groups: distal (569, 58.6%), proximal (284, 29.2%), and combined proximal and distal (118, 12.2%) groups. Subjects with advanced polyps in these three groups were 95 (9.8%),56 (5.8%), and 48 (4.9%) respectively. In the 48 subjects with advanced combined polyps, 13 advanced polyps were distributed at the distal colon, 17 at the proximal colon,and 18 at both. Eighteen colon cancers including 12 at sigmoid and 6 at ascending colon were confirmed by final pathology. The relative risk for advanced proximal polyp according to distal findings was 3.1 (95%CI: 1.3-7.4) for hyperplastic polyp, 2.7 (95%CI: 1.4-5.3) for tubular polyp and 13.5 (95%CI: 5.1-35.4) for advanced polyp as compared to that for no polyp. However, 56 (28.2%) of 199 subjects with advanced polyps had no index polyps at the distal colon and might go undetected under sigmoidoscopic screening.CONCLUSION: Although distal lesions can predict the risk of advanced proximal polyps, a substantial portion of Chinese with advanced proximal polyps is not associated with any distal sentinel lesions. These data have implications for screening policy of colon cancers in Taiwanese Chinese.