Juvenile polyposis

Massive Gastric Juvenile Polyposis: A Clinicopathologic Study Using SMAD4 Immunohistochemistry

OBJECTIVES

Juvenile polyps involving the stomach are uncommon. Massive gastric juvenile polyposis is even rarer.

METHODS

We describe the clinicopathologic features of nine cases of massive gastric juvenile polyposis.

RESULTS

All patients had anemia; four had hypoalbuminemia. The polyps were composed predominantly of dilated crypts lined by columnar epithelium and abundant edematous stroma with mixed inflammatory infiltrates. One patient had a poorly differentiated adenocarcinoma, arising in juvenile polyp-associated intraepithelial neoplasia. A second patient had a well-differentiated intramucosal adenocarcinoma arising in a juvenile polyp with high-grade dysplasia. Three of our cases had polyposis restricted to the stomach. Six (66.6%) had loss of SMAD4 immunoreactivity, making them subject to severe bleeding and hypoproteinemia, as well as developing severe dysplasia or adenocarcinoma.

CONCLUSIONS

SMAD4 immunohistochemstry is a helpful ancillary diagnostic test in cases of suspected juvenile polyposis syndrome involving the stomach.

Transforming Growth Factor β Superfamily Signaling in Development of Colorectal Cancer

Transforming growth factor (TGF)-β cytokines signal via a complex network of pathways to regulate proliferation, differentiation, adhesion, migration, and other functions in many cell types. A high percentage of colorectal tumors contain mutations that disrupt TGF-β family member signaling. We review how TGF-β family member signaling is altered during development of colorectal cancer, models of study, interaction of pathways, and potential therapeutic strategies.

Massive gastric polyposis associated with a germline SMAD4 gene mutation

Juvenile polyposis syndrome (JPS) is a rare autosomal dominant disorder characterized by the development of multiple hamartomatous polyps in the gastrointestinal tract. Polyps are most common in the colorectum (98% of patients) and the stomach (14%). Causative mutations for JPS have been identified in two genes to date, SMAD4 and BMPR1A. SMAD4 mutations are associated with a higher incidence of gastric polyposis. In this case report, we describe two patients with massive gastric polyposis associated with a SMAD4 mutation. Both presented with anaemia and both had colonic polyps. Initial endoscopic findings revealed giant rugal folds suggestive of Ménétrier disease. However, as other possible gastropathies could not be differentiated on the basis of histology, a definitive diagnosis of JPS required additional mutation analysis. In patients with polyposis predominant in or limited to the stomach, establishing a diagnosis based solely on the pathological features of polyps can be challenging due to difficulties in differentiating JPS from other hypertrophic gastropathies. Mutation analysis should be considered early in the diagnostic process in cases of suspected juvenile polyposis, thus facilitating rapid diagnosis and adequate follow-up.

Genotype-defined cancer risk in juvenile polyposis syndrome

Background

Germline mutations in SMAD4 and BMPR1A disrupt the transforming growth factor β signal transduction pathway, and are associated with juvenile polyposis syndrome. The effect of genotype on the pattern of disease in this syndrome is unknown. This study evaluated the differential impact of SMAD4 and BMPR1A gene mutations on cancer risk and oncological phenotype in patients with juvenile polyposis syndrome.

Methods

Patients with juvenile polyposis syndrome and germline SMAD4 or BMPR1A mutations were identified from a prospectively maintained institutional registry. Medical records were reviewed and the clinical patterns of disease were analysed.

Results

Thirty-five patients had germline mutations in either BMPR1A (8 patients) or SMAD4 (27). Median follow-up was 11 years. Colonic phenotype was similar between patients with SMAD4 and BMPR1A mutations, whereas SMAD4 mutations were associated with larger polyp numbers (number of patients with 50 or more gastric polyps: 14 versus 0 respectively). The numbers of patients with rectal polyps was comparable between BMPR1A and SMAD4 mutation carriers (5 versus 17). No patient was diagnosed with cancer in the BMPR1A group, whereas four men with a SMAD4 mutation developed gastrointestinal (3) or extraintestinal (1) cancer. The gastrointestinal cancer risk in patients with juvenile polyposis syndrome and a SMAD4 mutation was 11 per cent (3 of 27).

Conclusion

The SMAD4 genotype is associated with a more aggressive upper gastrointestinal malignancy risk in juvenile polyposis syndrome.

Appreciating the broad clinical features of SMAD4 mutation carriers: a multicenter chart review

Heterozygous loss-of-function SMAD4 mutations are associated with juvenile polyposis syndrome and hereditary hemorrhagic telangiectasia. Some carriers exhibit symptoms of both conditions, leading to juvenile polyposis-hereditary hemorrhagic telangiectasia syndrome. Three families have been reported with connective tissue abnormalities. To better understand the spectrum and extent of clinical findings in SMAD4 carriers, medical records of 34 patients (20 families) from five clinical practices were reviewed. Twenty-one percent of the patients (7/34) had features suggesting a connective tissue defect: enlarged aortic root (n = 3), aortic and mitral insufficiency (n = 2), aortic dissection (n = 1), retinal detachment (n = 1), brain aneurysms (n = 1), and lax skin and joints (n = 1). Juvenile polyposis-specific findings were almost uniformly present but variable. Ninety-seven percent of the patients had colon polyps that were generally pan-colonic and of variable histology and number. Forty-eight percent of the patients (15/31) had extensive gastric polyposis. Hereditary hemorrhagic telangiectasia features, including epistaxis (19/31, 61%), mucocutaneous telangiectases (15/31, 48%), liver arteriovenous malformation (6/16, 38%), brain arteriovenous malformation (1/26, 4%), pulmonary arteriovenous malformation (9/17, 53%), and intrapulmonary shunting (14/23, 61%), were documented in 76% of the patients. SMAD4 carriers should be managed for juvenile polyposis and hereditary hemorrhagic telangiectasia because symptoms of both conditions are likely yet unpredictable. Connective tissue abnormalities are an emerging component of juvenile polyposis-hereditary hemorrhagic telangiectasia syndrome, and larger studies are needed to understand these manifestations.

Familial juvenile polyposis syndrome with a novel SMAD4 germline mutation

Juvenile polyposis syndrome (JPS) is a dominantly inherited disorder characterized by the development of numerous juvenile polyps (JPs) of the gastrointestinal tract, and associated with a mutation of the SMAD4 or BMPR1A gene. Here, we report a mother-daughter case of familial JPS. A 29-year-old female patient with severe iron deficiency anemia and hypoproteinemia had numerous polyps in the stomach and a few polyps in the ileum and colon that were detected endoscopically. Biopsy specimens from the gastric polyps were diagnosed as JPs. The patient underwent a laparoscopy-assisted total gastrectomy, and her anemia and hypoproteinemia improved. Her mother also had multiple JPs in the stomach, duodenum, jejunum, and colon. We then diagnosed them as having familial JPS. Moreover, germline mutation analysis of the 2 patients presented a novel pathogenic SMAD4 variant.

Colorectal polyps in childhood

PURPOSE OF REVIEW

Colorectal polyps are a common cause of gastrointestinal bleeding in children. This review updates the information on colorectal polyps and summarizes the recent advances in genetics, diagnosis, and treatment of polyps in the large intestine.

RECENT FINDINGS

A review of recent literature regarding colorectal polyps demonstrates an estimated detected prevalence of 6.1% overall and 12.0% among those with lower gastrointestinal bleeding during pediatric colonoscopy. Non-Caucasian races (e.g., black and Hispanic) are at higher risk for colorectal polyps in childhood. Recent data show juvenile polyps may recur in approximately 45% of children with multiple polyps and 17% of children with solitary polyps. A clinical trial showed that celecoxib, a cyclooxygenase (COX)-2 inhibitor, significantly reduced the number of colorectal polyps in children with familial adenomatous polyposis (FAP). Ethical challenges related to genetic tests for FAP have been newly examined. The utility of novel endoscopic techniques (e.g., enteroscopy) in Peutz-Jeghers Syndrome to prevent intussusception have been newly described.

SUMMARY

Although colorectal polyps in children are generally benign and easily removed, careful clinical evaluation and ongoing research are needed to identify the small proportion of children at risk for cancer. The current paradigm of using the polyp number at presentation as a primary determinant of subsequent surveillance may be inadequate for many patients.

Manifestations of juvenile polyposis syndrome in SMAD4 mutation carriers of a kindred

The autosomal dominantly inherited juvenile polyposis syndrome (JPS) leads to the development of multiple hamartomatous polyps in the gastrointestinal tract and is a precancerous condition. In a large family with a newly identified SMAD4 mutation (c.543delC), we describe the clinical manifestations of JPS. Nine affected SMAD4 mutation-positive family members were screened and treated for manifestations of JPS. Two family members were symptomatic at the time of diagnosis; seven were asymptomatic - independent of the severity of the manifestation. Each mutation carrier presented with colonic juvenile polyps, seven out of nine with additional gastric manifestations. One asymptomatic patient had early gastric cancer; another patient had a villous adenoma with high-grade intraepithelial neoplasia in the colon. Three patients had biliary lesions including a bile duct hamartoma in one and gallbladder polyps in two. Three patients had gastrointestinal vascular malformations. All mutation carriers were affected by JPS. Interestingly, the manifestations and their severity differed considerably between the patients, suggesting secondary factors influencing JPS manifestations such as Helicobacter pylori infection.

Histologic variations in juvenile polyp phenotype correlate with genetic defect underlying juvenile polyposis

BACKGROUND

Juvenile polyps are distinct hamartomatous malformations of the gastrointestinal tract that may occur in the heritable juvenile polyposis syndrome (JPS) or sporadically. Histologically, juvenile polyps are characterized by a marked increase of the stromal cell compartment, but an epithelial phenotype has also been reported. JPS has an increased risk of colorectal cancer but sporadic juvenile polyps do not. In 50% to 60% of patients with JPS, a germline mutation of the transforming growth factor-β/bone morphogenetic protein (BMP) pathway genes SMAD4 or BMPR1A is found. This study compares the histologic phenotype of juvenile polyps with a SMAD4 or BMPR1A germline mutation and sporadic juvenile polyps.

METHODS

Hematoxylin and Eosin-stained slides of 65 JPS polyps and 25 sporadic juvenile polyps were reviewed for histologic features and dysplasia. Systematic random crypt and stroma counts were obtained by count stereology, and a crypt-stroma ratio was determined. All polyps were subsequently categorized as type A (crypt-stroma ratio <1.00) or type B (crypt-stroma ratio ≥1.00), the latter referring to the epithelial phenotype. Cell cycle activity was assessed using immunohistochemistry ofthe proliferation marker Ki67, and mutation analysis was carried out for KRAS and APC to determine the involvement of the adenoma-carcinoma sequence.

RESULTS

Juvenile polyps with a SMAD4 germline mutation were predominantly type B, whereas type A was more common among juvenile polyps with a BMPR1A germline mutation. However, this distinction could not be ascribed to differences in cell cycle activity. Dysplasia was equally common in JPS polyps with either a SMAD4 or BMPR1A germline mutation, in which the involvement of the adenoma-carcinoma sequence does not seem to play a distinct role.

CONCLUSION

Juvenile polyps in the setting of JPS exhibit distinct phenotypes correlating with the underlying genetic defect.

Extracolonic manifestations of hereditary colorectal cancer syndromes

Familial colorectal adenocarcinoma (CRC) accounts for approximately 15 to 20% of CRC. Of these, hereditary nonpolyposis colorectal cancer (HNPCC) and familial adenomatous polyposis (FAP) represent the most common hereditary syndromes associated with CRC, followed by other less common diseases including juvenile polyposis (JP) and Peutz-Jeghers syndrome (PJS). Extracolonic manifestations are common in each of these syndromes having significant implications for surveillance and management in at-risk individuals. The authors review the most common and clinically relevant extracolonic manifestations for each of these syndromes focusing on incidence, presentation, genotype/phenotype correlations, and management (including surveillance) strategies.

Matrix metalloproteinases in the urine and tissue of patients with juvenile polyps: potential biomarkers for the presence of polyps

BACKGROUND AND AIMS

Juvenile polyps are the most common type of pediatric gastrointestinal polyp and are typically characterized as hamartomatous overgrowths. Juvenile polyps are highly vascularized tissues and display a markedly increased mucosal microcirculation. Matrix metalloproteinases (MMPs) are a family of zinc-dependent enzymes that play an essential role in the physiological degradation of the extracellular matrix in normal development, tumor invasion, and metastasis, as well as angiogenesis. We hypothesized that the presence of these enzymes in urine may serve as clinical biomarkers of juvenile polyps.

PATIENTS AND METHODS

In this preliminary study, we analyzed 32 urine samples collected prospectively from 16 subjects with known or suspected juvenile polyps who presented to the endoscopy unit for colonoscopic evaluation and 16 age- and sex-matched controls. Urinary MMPs were analyzed by zymography and their localized tissue expression was assayed via immunohistochemistry of tissue sections.

RESULTS

MMPs were detected in the urine of patients with juvenile polyps with significantly higher frequency when compared with urine of control subjects. In addition, immunohistochemistry demonstrated that high levels of MMPs were localized in the epithelium and lamina propria of polyp tissue when compared with colonic tissue collected from healthy control subjects.

CONCLUSIONS

These data are the first to demonstrate that MMPs are present in the urine and tissue of patients with juvenile polyps, and these enzymes have the potential to serve as surrogate markers for the presence of polyps.

Juvenile polyposis syndrome

AIM

Report of a series of 12 cases of juvenile polyposis coli.

METHODS

The study period was from 1995 to 2005. All the patients were treated by total colectomy with rectal mucosectomy and endorectal ileoanal pullthrough with or without ileal pouch formation. Covering ileostomy was avoided in all the cases. Time taken for the surgery, postoperative complications and continence were documented.

RESULTS

The mean operating time was 4.2 h (range: 4-5 h). The mean duration of hospital stay was 16.3 days (range: 15-18 days). The most common postoperative complication was pouchitis and perianal excoriation. Initially, all the patients were passing stools at an interval of 2 h, and after 3 weeks, the frequency has reduced to 6-8 stools per day. In the follow-up after 3 months, the frequency was 3-5 per day with minimal soiling.

CONCLUSIONS

Single-stage total colectomy with rectal mucosectomy and endorectal ileoanal pull-through without covering ileostomy and pouch formation is a safe and definitive treatment for juvenile polyposis coli if the patient selection is appropriate.

Hamartomatous polyposis syndromes

Since the histologic description of the hamartomatous polyp in 1957 by Horrilleno and colleagues, descriptions have appeared of several different syndromes with the propensity to develop these polyps in the upper and lower gastrointestinal tracts. These syndromes include juvenile polyposis, Peutz-Jeghers syndrome, hereditary mixed polyposis syndrome, and the phosphatase and tensin homolog gene (PTEN) hamartoma tumor syndromes (Cowden and Bannayan-Riley-Ruvalcaba syndromes), which are autosomal-dominantly inherited, and Cronkhite-Canada syndrome, which is acquired. This article reviews the clinical aspects, the molecular pathogenesis, the affected organ systems, the risks of cancer, and the management of these hamartomatous polyposis syndromes. Although the incidence of these syndromes is low, it is important for clinicians to recognize these disorders to prevent morbidity and mortality in these patients, and to perform presymptomatic testing in patients at risk.

[Sporadic colonic juvenile polyps in adults]

Sporadic colonic juvenile polyps are uncommon in adults. We report three cases for which clinical manifestations were presence of occult blood in the stool, rectal bleeding or chronic diarrhea. Two of these polyps occurred in the caecum which is an uncommon localisation. Endoscopic characteristics of these polyps were indistinguishable from adenomas. Endoscopic resection was complicated in one case by bleeding.

Reducing the incidence and mortality of colon cancer: mass screening and colonoscopic polypectomy

Most colon cancers arise from conventional adenomatous polyps (conventional adenoma-to-carcinoma sequence), while some colon cancers appear to arise from the recently recognized serrated adenomatous polyp (serrated adenoma-to-carcinoma theory). Because conventional adenomas and serrated adenomas are usually asymptomatic, mass screening of asymptomatic patients has become the cornerstone for detecting and eliminating these precursor lesions to reduce the risk of colon cancer. Colonoscopy has become the primary screening test because of its high sensitivity and specificity, and the ability to perform polypectomy. Other screening tests include guaiac tests or fecal immunochemical tests (FIT) for fecal occult blood, and flexible sigmoidoscopy. A minimal colonoscopic withdrawal time of 6 minutes is important to maximize polyp detection at colonoscopy. Chromoendoscopy is an experimental technique used to highlight abnormal colonic areas to identify neoplastic tissue and to potentially determine the histology of colonic polyps at colonoscopy based on superficial pit anatomy.

Juvenile polyposis of the stomach causing recurrent upper gastrointestinal bleeding

We present the case of a 42-year-old man who suffered from recurrent severe upper gastrointestinal bleeding starting from February 2003. Endoscopy showed multiple glassy polyps in the stomach, which corresponded to a diffuse mucosal thickening detected by endosonography. The duodenum was normal. In February 2006, life-threatening acute gastrointestinal bleeding prompted total gastrectomy. The resection specimen showed the gastric mucosa carpeted by numerous glassy pedunculated polyps, measuring 2 cm in largest diameter. Histologically, the polyps were characterized by an abundant loose stroma and by elongated, twisting foveolae, covered by hyperplastic epithelium. Colonoscopy including the terminal ileum revealed a single tubulovillous adenoma, but no hamartomatous polyps, rendering a final diagnosis of juvenile polyposis of the stomach. This case represents the first description of juvenile polyposis causing life-threatening gastric haemorrhage. Thus, although rare, the disease has to be considered in the differential diagnosis of patients with acute upper gastrointestinal tract bleeding.

Conditional deletion of beta1 integrins in the intestinal epithelium causes a loss of Hedgehog expression, intestinal hyperplasia, and early postnatal lethality

Conditional deletion of β1 integrins in the intestinal epithelium, unlike in epidermal and mammary epithelia, of mice does not result in decreased cell adhesion and proliferation, but instead causes a profound increase in epithelial proliferation with dysplasia and polypoid structures. The increased epithelial proliferation inhibited epithelial differentiation that caused severe malnutrition and early postnatal lethality. The striking similarities between β1 integrin–deleted mice and neonatal mice with defective Hedgehog signaling led to the discovery that Hedgehog expression was markedly reduced in the former mice. β1 integrins were found to drive the expression of Hedgehogs in intestinal epithelial cells in an HNF-3β (Foxa2)–dependent fashion. The expression of Tcf-4, a transcription factor known to be required for intestinal epithelial stem cell proliferation, was increased and mislocalized in the intestinal epithelia of the β1 integrin–deleted mice and in newborn mice treated with the Hedgehog signaling inhibitor cyclopamine. This study shows that β1 integrins are key regulators of proliferation and homeostasis in the intestine and achieve this not through anchorage-dependent effects but by generating Hh expression and signaling.

Mutation screening in juvenile polyposis syndrome

Juvenile polyposis syndrome (JPS) is an autosomal dominant cancer predisposition syndrome characterized by congenital anomalies, hamartomatous polyps in the gastrointestinal tract, and the development of tumors in these tissues. The diagnosis of JPS is often difficult because of the phenotypic overlap with other hamartomatous polyposis syndromes. Germline mutations have been identified in MADH4 and BMPR1A, aiding in presymptomatic genetic testing. In this study, we describe the results from 3 years of molecular diagnostic screening in JPS. Seventy unrelated individuals referred to our lab for JPS testing were examined through the sequence analysis of coding regions and exon-intron boundaries in both genes. Germline mutations were identified in 30% of cases, with 11.4% in BMPR1A and 18.6% in MADH4. All mutation-positive individuals were negative for cancer at testing, and a single pulmonary valve stenosis was the only congenital anomaly reported. A majority of mutations identified were novel including the first splice site alteration in MADH4. Based on the limited number of exons in each gene, low polymorphism frequency, and high frequency of frameshift or nonsense mutations identified, direct sequence analysis is a suitable methodology for mutation screening if all coding regions and exon-intron boundaries are examined in both genes.

Gastrointestinal tumors in children and adolescents

Tumors of the pediatric gastrointestinal tract are extremely rare. Their infrequent presentation at treatment centers has not allowed for the development of standardized treatment protocols and prospective review. The most prevalent gastrointestinal neoplasms and malignancies are described, including gastrointestinal lymphoma, colorectal carcinoma, carcinoid tumors, gastrointestinal stromal tumors, leiomyomas, juvenile polyps, inflammatory pseudotumors, gastric tumors, and Peutz-Jeghers polyposis syndrome. Current recommendations for the medical and surgical management of these tumors are reviewed and summarized for this vast group of gastrointestinal neoplasms in children.

Juvenile polyposis coli: a facultative precancerosis with some similarities to ulcerative colitis?

We investigated the case of a 13-year-old male with juvenile polyposis (JP) to determine the extent of intraepithelial neoplasia and associated genetic changes, as well as cellular proliferation, within these polyps using immunohistochemistry with antibodies against p53, bcl-2, and Ki-67. Examination of the total proctocolectomy specimen revealed 70 polyps. The 18 largest polyps were investigated microscopically and disclosed the typical hamartomas with frequent erosions of the surface epithelium and reparative changes. Only one polyp showed focal low-grade intraepithelial neoplasia. The immunohistochemical studies revealed an expression of p53 and an abnormal Ki-67 pattern of the surface epithelium only within the neoplastic area. These findings may hint at a possible pathogenetic mechanism for the evolution of colorectal cancer in JP. As in ulcerative colitis, carcinomas in JP may develop along a dysplasia-carcinoma sequence resulting from permanent mechanical insults, inflammation, and repair rather than from an adenoma-carcinoma sequence as in familial adenomatous polyposis (FAP).

Inherited polyposis syndromes: molecular mechanisms, clinicopathology, and genetic testing

The inherited polyposis syndromes are a group of conditions in which multiple gastrointestinal polyps occur in the lumen of the gastrointestinal tract, most exhibit an increased risk of colon cancer. Benign and malignant extraintestinal tumors might also be observed. Recent elucidation of the underlying gene mutations has contributed to our understanding of the cell biology and molecular mechanisms associated with gastrointestinal tumorigenesis. Developments have also allowed genetic testing to become an integral component in accurate diagnosis, categorization, and management of inherited polyposis syndromes. In this review, we will focus on familial adenomatous polyposis, mutY human homologue-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis, and Cowden syndrome. It is essential that both physician and patient understand the benefits and limitations of genetic testing before submission of samples to the laboratory. There are many issues accompanying molecular diagnosis of cancer syndromes, and genetic counseling is an essential prelude to genetic testing.

From Colonic Polyps to Colon Cancer: Pathophysiology, Clinical Presentation, and Diagnosis

Epidemiologists, basic researchers, clinicians, and public health administrators unite! Develop and implement a simple, safe, and effective preventive and screening test for colon cancer. The public will willingly and enthusiastically accept such a test. Many thousands of lives are at stake every year.

Characteristics of familial juvenile polyps expressing cyclooxygenase-2

OBJECTIVES

Familial juvenile polyposis (FJP) is a dominant genetic disorder characterized by colorectal, gastric, and small bowel juvenile polyps, and high risk for gastrointestinal cancer. Patients are treated by repeated endoscopic polypectomies and elective surgery. We determined the characteristics of FJP polyps expressing cyclooxygenase-2 (COX-2).

METHODS

A total of 115 colorectal and 6 gastric polyps were available from 17 FJP patients. Comparison tissues were 18 sporadic juvenile colorectal polyps, 6 gastric hyperplastic polyps, 9 normal colons, and 3 colorectal cancers (CRCs). Histology sections were classified and stained for COX-2. The polyps' epithelium and stroma and comparison tissues were quantified for COX-2 by: area of staining (0-3) x intensity (0-3). Epithelial and stromal scores (0-9) and total scores (0-18) were evaluated in relationship to patient's age, polyp site, size, dysplasia, and stromal cellularity.

RESULTS

Colonic FJP polyps mean total COX-2 score was 10.3 +/- 6.0, and that of sporadic juvenile polyps 3.6 +/- 2.2 (p < 0.01), and in contrast to the latter, FJP COX-2 scores increased significantly (p < 0.01) with polyp size. Linear regression analysis showed significant associations of COX-2 in FJP polyps with dysplasia (p < 0.01), stromal cellularity (p < 0.01), size (> or =1.5 cm) (p= 0.02), and site (right colon) (p= 0.01), and not with age. COX-2 total scores of gastric FJP polyps and hyperplastic polyps were similar.

CONCLUSIONS

Expression of COX-2 in FJP polyps and its association with size and dysplasia suggest that, in these patients, chemoprevention with selective COX-2 inhibitors might be a useful adjunct therapy to colonoscopic polypectomy.

The pathophysiology, clinical presentation, and diagnosis of colon cancer and adenomatous polyps

A review of the pathophysiology, clinical presentation, and diagnosis of colon cancer and colonic polyps is important and timely. This field is rapidly changing because of breakthroughs in the molecular basis of carcinogenesis and in the technology for colon cancer detection and treatment. This article reviews colon cancer and colonic polyps, with a focus on recent dramatic advances, to help the pri-mary care physician and internist appropriately refer patients for screening colonoscopy and intelligently evaluate colonoscopic findings to reduce the mortality from this cancer.

Colonic surgery in patients with juvenile polyposis syndrome: a case series

PURPOSE

Juvenile polyposis syndrome is characterized by multiple hamartomatous polyps in the large intestine. When indicated, the surgical choices in symptomatic juvenile polyposis syndrome patients are colectomy with ileorectal anastomosis or proctocolectomy with pouch. The aim of this study was to evaluate the long-term outcomes of the surgical options in juvenile polyposis syndrome patients who present with symptomatic colonic polyps.

METHODS

The charts of all juvenile polyposis syndrome patients who had had at least one colonic operation since 1953 in our institution were reviewed. The following data were abstracted: demographics, the number and site of the polyps, symptoms, the intervals and types of the colonic operation, follow-up, and the patients' current status.

RESULTS

There were 13 patients (6 males) with a median age of 10 years (range, 1-50 years) at the time of diagnosis. Patients had colonic (n = 13), rectal (n = 12), and gastric (n = 6) polyps. Rectal bleeding (n = 11) was the most common presenting symptom. Three patients underwent proctectomy as the initial operation. Although a rectum-preserving operation was initially performed in ten patients, a subsequent proctectomy was required in five of them within a median of 9 years (range, 6-34 years). Therefore, eight patients had their rectum removed during the study period; five had an ileal pouch-anal anastomosis, one had a Koch pouch as a restorative surgery, and two had an end ileostomy. No relation was observed between the number of colonic and rectal polyps and the type of surgery or the need for proctectomy. Patients were followed up a median of 3 years (range, 2-24 years) after their ultimate operations. During this period, one patient (20 percent) who underwent restorative proctectomy and 4 patients (80 percent) whose rectums were preserved required multiple endoscopic polypectomies for recurrent polyps in the pouch (first patient) or their rectums (the other four patients). The patient who underwent the Koch procedure required surgery for recurrent polyps in her pouch.

CONCLUSIONS

One-half of the patients who initially underwent rectal preservation required subsequent proctectomy. The number of colonic or rectal polyps does not influence the choice of the surgical procedure. Both restorative proctocolectomy and subtotal colectomy with ileorectal anastomosis need endoscopic follow-up because of the high recurrence rates of juvenile polyps in the remnant rectum or pouch.

Highly penetrant hereditary cancer syndromes

The past two decades have brought many important advances in our understanding of the hereditary susceptibility to cancer. Approximately 5-10% of all cancers are inherited, the majority in an autosomal dominant manner with incomplete penetrance. While this is a small fraction of the overall cancer burden worldwide, the molecular genetic discoveries that have resulted from the study of families with heritable cancer have not only changed the way these families are counselled and managed, but have shed light on molecular regulatory pathways important in sporadic tumour development as well. In this review, we consider 10 of the more highly penetrant cancer syndromes, with emphasis on those predisposing to breast, colon, and/or endocrine neoplasia. We discuss the prevalence, penetrance, and tumour spectrum associated with these syndromes, as well as their underlying genetic defects.

Gastrointestinal polyposis syndromes

Numerous polyposis syndromes involve the gastrointestinal (GI) tract, including both non-hereditary and hereditary types. Causative genes are now known for the seven major syndromes. Genetic and clinicopathologic features are reviewed here and cancer predisposition is emphasized. Genetic testing is available for the GI polyposis syndromes, and can be accessed through GeneTests-GeneClinics on the Internet at http://www.genetests.org/. The website is available at no cost and is a publicly funded medical genetics resource for health care providers and researchers.

An audit of familial juvenile polyposis at the Tel Aviv Medical Center: demographic, genetic and clinical features

Familial juvenile polyposis (JP) is an uncommon genetic disorder that, if untreated, can lead to gastrointestinal cancer. To evaluate familial JP prevalence, phenotypic manifestations, causative mutations, treatment and compliance for diagnosis and follow-up in our registry. Since 1993 our familial JP patients were registered, followed-up before and/or after surgery and their families encouraged to have mutation analysis, endoscopic screening and treatment. Ten pedigrees were identified, all Jewish, but only one was Ashkenazi, six were Sepharadi and three were Oriental; the only mutation found was BMPR1A in two of six pedigrees examined. Of 139 first-degree relatives at risk for JP, 62 (45%) had JP or cancer; 56 (40.3%) were available for follow-up and 35 entered the registry. Of these, 71% reported rectal bleeding, 40% had <20 colonic polyps, 31% had 20-100 polyps; 2 had >100 gastric polyps. Cancer occurred in 22.9% (6 colonic, 2 gastric) before familial JP diagnosis or during follow-up elsewhere or non-compliance for follow-up; however, 1 gastric cancer developed during our treatment. In 46% the initial clinical-pathological diagnosis was incorrect. Compliance for evaluation and follow-up of pedigree members and individual familial JP patients was inadequate in 20% and 26%, respectively. Familial JP does not occur in the Israeli Ashkenazi Jewish population at the expected proportion; it is often misdiagnosed and is inadequately recognized in Israeli non-Jews. Mutations were identified in only a minority of pedigrees despite comprehensive screening. The inadequate compliance for screening and follow-up needs to be addressed by educating the public, health care workers and health insurances.

Heritable colorectal cancer syndromes: recognition and preventive management

Familial CRC syndromes account for a small yet important portion of colorectal malignancies. HNPCC, FAP, JPS, and Peutz-Jeghers syndrome are the four major conditions to r to consider if an hereditary condition is suspected in an individual with CRC. A multidisciplinary team comprised of a medical geneticist, gastroenterologist, pathologist, radiologist, and colorectal surgeon with expertise in recognizing and establishing the diagnosis of a specific familial cancer condition is crucial to implementing the proper management and prevention strategies unique to each of these syndromes. Genetic testing for each of these coniditions is available and useful for presymptomatic diagnosis and for indicated surveillance regimens. Vigilant endoscopic surveillance and careful timing of surgery are the mainstays of prevention for gastrointestinal malignancies. But with the advancement of genetic evaluation, improved cancer surveillance for intestinal as well as extraintestinal cancer, and chemopreventive strategies, the management of patients with a familial CRC syndrome will continue to evolve and, hopefully, significantly reduce their cancer burden.

Juvenile polyposis of the colon: sonographic diagnosis

Juvenile polyposis is an uncommon condition characterized by development of multiple juvenile polyps, predominantly in the colon but also in the rest of the gastrointestinal tract. The condition usually appears in childhood. The rarer and often fatal form, occurring in infancy, is typified by diarrhea, protein-losing enteropathy, bleeding, and rectal prolapse. The more common form of juvenile polyposis (affecting the colon, stomach, and small bowel) occurs in the first or second decade with rectal bleeding and anemia. We report a case of juvenile polyposis detected on sonography, which had been treated as severe anemia for 1 year.

Hamartomatous polyposis syndromes: genetic pathways

Hamartomatous polyposis syndromes are a group of clinically distinct but perhaps genetically related disorders in which the predominant finding is multiple hamartomatous polyps in the gastrointestinal tract. These syndromes are transmitted in an autosomal dominant fashion to offspring, but sporadic forms do exist in which the biological parents lack an identified germline mutation. Despite the nondysplastic histologic characteristics of their polyps, each hamartomatous syndrome carries an elevated risk for cancer at specific organ sites. Several genes have been identified as mutated in the germline from these syndromes, and they provide clues to the pathogenesis of the polyps and may explain some of the elevated cancer risk. Pathways involved in the hamartomatous syndromes include those of vascular endothelial growth factor, the transforming growth factor beta superfamily, and antagonizing the effects of Akt/protein kinase B.

Hamartomatous polyposis syndromes: molecular genetics, neoplastic risk, and surveillance recommendations

Hamartomatous polyposis syndromes are characterized by an overgrowth of cells or tissues native to the area in which they normally occur. Juvenile polyposis syndrome (JPS) results from germ-line mutations in the SMAD-4 gene (18q21.1) that encodes for an enzyme involved in transforming growth factor beta(TGF-beta) signal transduction. The increased neoplastic risk may result from SMAD-4 mutations in the stromal component, which stimulate epithelial dysplasia and progression to invasive malignancy. Peutz-Jeghers syndrome (PJS) is associated with germ-line mutations in the LKB1 gene (19p13.3) that encodes a multifunctional serine-threonine kinase. These mutations occur in the epithelial component, suggesting a direct tumor suppressor effect. Patients are at an increased risk of intestinal and extraintestinal malignancies, including breast, pancreatic, ovarian, testicular, and cervical cancer. Cowden's disease is associated with germ-line mutations in the PTEN gene (10q22-23) and an increased risk of breast and thyroid malignancies. Ruvalcaba-Myhre-Smith syndrome is less common; controversy suggests that it may represent a variant of Cowden's disease.

CONCLUSIONS

Genetic alterations underlying hamartomatous polyposis syndromes are diverse. Carcinogenesis may result from either germ-line mutations in the stroma (JPS) or as a direct result of functional deletion of tumor suppressor genes (PJS). Diagnosis depends on clinical presentation and patterns of inheritance within families. Suggested surveillance guidelines for the proband and first-degree relatives are outlined.

Germline mutations of the dpc4 gene in Korean juvenile polyposis patients

Juvenile polyposis is an uncommon condition characterized by the development of multiple (usually more than 5) juvenile polyps in the gastrointestinal tract, especially in the colon. This disease usually occurs during childhood, and is inherited in an autosomal dominant fashion. It has been suggested that the dpc4 (deleted in pancreatic carcinoma, locus 4) gene, which is located on chromosome 18q21.1, might cause juvenile polyposis. The dpc4 (smad4) gene is a candidate tumor-suppressor gene and may play a role in the TGF-beta-signaling pathway. To confirm the idea that alterations of the dpc4 gene may result in juvenile polyposis, we screened 5 Korean juvenile-polyposis patients by PCR-SSCP (single-strand conformation polymorphism) analysis and bi-directional sequencing. There were germline mutations of the dpc4 gene in 3 out of the 5 patients: 2 had a genetic alteration in exon 9 and the third had a mutation in exon 8. These germline mutations occurred in the C-terminus of the dpc4 gene, similar to most published mutations. One patient exhibited a non-sense mutation (codon 388), which changed a glutamine codon (CAG) to a stop codon (TAG). The second patient harbored a mis-sense mutation (codon 390), causing a non-conservative amino-acid change <glutamate (GAA) to lysine (AAA)>. The third patient had a mis-sense mutation in exon 8 (codon 361), which altered an arginine codon (CGC) into a histidine codon (CAC).

Gastro-intestinal tumorigenesis in Smad4 mutant mice

The SMAD4 gene plays a key role in the TGF-beta signaling pathway. We inactivated its mouse homolog Smad4. The homozygous mutants were embryonically lethal, whereas the heterozygotes were viable and fertile. Although young heterozygotes appeared normal, old mice developed gastric and duodenal polyps similar to human juvenile polyps characterized by abundant stroma and eosinophilic infiltrations. These data are consistent with the reports that a subset of human juvenile polyposis kindreds carry germline mutations in the SMAD4 gene. We then introduced the Smad4 mutation into the Apc(Delta716) knockout mice, a model for human familial adenomatous polyposis. Because both Apc and Smad4 are located on mouse chromosome 18, we constructed by meiotic recombination compound heterozygotes carrying both mutations on the same chromosome. In such mice, intestinal polyps developed into more malignant tumors than those in the simple Apc(Delta716) heterozygotes, showing an extensive stromal cell proliferation and strong submucosal invasion. These results indicate that mutations in SMAD4 play a significant role in the malignant progression of colorectal tumors.

Clinical implications of multiple colorectal carcinomas in hereditary nonpolyposis colorectal carcinoma

PURPOSE

An increased incidence of multiple (synchronous and metachronous) colorectal carcinomas has been reported in hereditary nonpolyposis colorectal cancer. This review was undertaken to determine the clinical implications of multiple colorectal carcinomas in hereditary nonpolyposis colorectal cancer.

METHODS

A retrospective review of the records of patients in the hereditary nonpolyposis colorectal cancer registry at Roswell Park Cancer Institute who had either synchronous or metachronous colorectal carcinomas was conducted.

RESULTS

Twenty-five of 93 patients with documented pathology were found to have multiple colorectal carcinomas. The mean age at diagnosis of the index colorectal carcinoma was 46.7 (range, 28-65) years. There were 7 (7.5 percent) patients with synchronous colorectal carcinomas and 20 (21.5 percent) patients with metachronous colorectal carcinomas. Two of the seven (28.6 percent) patients with synchronous colorectal carcinomas developed a metachronous colorectal carcinoma. In the patients with metachronous colorectal carcinomas, 29 metachronous events were noted: colon (23) and rectum (6). The mean and median time interval for metachronous colorectal carcinomas were 10.9 and 11.8 (range, 1.5-43.8) years, respectively. The mean times to first, second, and third events were 11.7 (range, 1.5-43.5), 7.9 (range, 2.7-18.7), and 12.3 (range, 11.8-12.7) years, respectively. The majority of patients with metachronous colorectal carcinomas did not have stage progression at the diagnosis of the metachronous colorectal carcinomas: 13 patients had lower or same stage at first event, 4 had lower or same stage at second event, and 2 patients had lower stage at third event. Three of 20 patients with metachronous colorectal carcinomas died of their disease.

CONCLUSION

Multiple colorectal cancers are common in hereditary nonpolyposis colorectal cancer. Even though stage progression may not be evident at diagnosis of metachronous colorectal cancer, some of these patients will nevertheless die of their disease.

An unusual cause of rectal bleeding in a patient with cystic fibrosis

Here we identify a previously unreported cause of rectal bleeding (juvenile polyposis) in a patient with cystic fibrosis (CF). We believe this patient most likely has two coexisting genetic diseases. It also raises many issues about organ transplantation in a patient with medical conditions that individually increase the risk of gastrointestinal malignancy and stresses the diagnostic value of endoscopy in CF patients with rectal bleeding.