Pachydysostosis of the fibula in a case of familial adenomatous polyposis

BACKGROUND

Familial Adenomatous Polyposis (FAP) is a colorectal cancer (CRC) predisposition syndrome caused by germline APC mutations and characterised by an increased risk of CRC and colonic polyps and, in certain forms, of specific prominent extraintestinal manifestations, namely osteomas, soft tissue tumours and dental anomalies. Pachydysostosis of the fibula is a rare clinical entity defined by unilateral bowing of the distal portion of the fibula and elongation of the entire bone, without affectation of the tibia.

CLINICAL REPORT

We report a 17-year-old male, who presented with a non-progressive bowing of the right leg detected at 18 months of age caused by a fibula malformation (later characterized as pachydysostosis) and a large exophytic osteoma of the left radius, noticed at the age of 15 years, without gastrointestinal symptoms. There was no relevant family history. Detailed characterisation revealed multiple osteomas, skin lesions and dental abnormalities, raising the hypothesis of FAP. This diagnosis was confirmed by genetic testing [c.4406_4409dup p.(Ala1471Serfs*17) de novo mutation in the APC gene] and endoscopic investigation (multiple adenomas throughout the colon, ileum and stomach).

DISCUSSION

This case report draws attention to the phenotypic spectrum of skeletal manifestations of FAP: this patient has a congenital fibula malformation, not previously associated with this syndrome, but which is likely to have been its first manifestation in this patient. This clinical case also illustrates the challenges in the early diagnosis of FAP, especially without family history, and highlights the importance of a multidisciplinary approach and the adequate study of rare skeletal abnormalities.

Pathology of Gastrointestinal Polyposis Disorders

Gastrointestinal polyposis disorders are a group of syndromes defined by clinicopathologic features that include the predominant histologic type of colorectal polyp and specific inherited gene mutations. Adenomatous polyposis syndromes comprise the prototypical familial adenomatous polyposis syndrome and other recently identified genetic conditions inherited in a dominant or recessive manner. Serrated polyposis syndrome is defined by arbitrary clinical criteria. The diagnosis of hamartomatous polyposis syndromes can be suggested from the histologic characteristics of colorectal polyps and the association with various extraintestinal manifestations. Proper identification of affected individuals is important due to an increased risk of gastrointestinal and extragastrointestinal cancers.

Surveillance Compliance and Quality of Life Assessment Among Surgical Patients with Familial Adenomatous Polyposis Syndrome

BACKGROUND

Familial adenomatous polyposis (FAP) syndrome has a near-100% lifetime risk of colorectal cancer. Early surveillance and prophylactic surgery have been advocated to reduce this risk. However, the surveillance practices among FAP individuals in Saudi Arabia are unknown. We aimed to explore surveillance compliance in our population, as well as the disease impact on their quality of life (QoL).

METHODS

All patients with FAP who underwent surgical resection at King Saud University Medical City between 2016 and 2022 were included. Demographic data, clinical features, family history, and compliance with surveillance were collected and analyzed. QoL questionnaires: Short-form health survey (SF-36) and European Organization for Research and Treatment (EORTC) were conducted by phone interview.

RESULTS

A total of 14 patients were included with an average age of 25 years. Three patients (21.4%) were the first of their family members to develop FAP. Nine patients (64%) were untested for genetic mutation due to lack of referral to geneticists. The compliance rate toward both pre-operative colonoscopy and upper endoscopy were 78%. However, 38% and 27% compliance rates were observed toward initial and post-operative colonoscopy, respectively. The compliance rate was 14% toward thyroid ultrasound. QoL scores varied among patients, with a mean score above 60 across all SF-36 domains.

CONCLUSION

An overall poor compliance was observed among our participants, particularly toward thyroid ultrasound. Increased health awareness and patient education are essential. In addition, the importance of surveillance and genetic counseling should be emphasized among physicians treating these patients.

Solving Missing Heritability in Patients With Familial Adenomatous Polyposis With DNA-RNA Paired Testing

PURPOSE

Patients with germline pathogenic variants (PVs) in APC develop tens (attenuated familial adenomatous polyposis [AFAP]) to innumerable (classic FAP) adenomatous polyps in their colon and are at significantly increased lifetime risk of colorectal cancer. Up to 10% of FAP and up to 50% of patients with AFAP who have undergone DNA-only multigene panel testing (MGPT) do not have an identified PV in APC. We seek to demonstrate how the addition of RNA sequencing run concurrently with DNA can improve detection of germline PVs in individuals with a clinical presentation of AFAP/FAP.

METHODS

We performed a retrospective query of individuals tested with paired DNA-RNA MGPT from 2021 to 2022 at a single laboratory and included those with a novel APC PV located in intronic regions infrequently covered by MGPT, a personal history of polyposis, and family medical history provided. All clinical data were deidentified in this institutional review board-exempt study.

RESULTS

Three novel APC variants were identified in six families and were shown to cause aberrant splicing because of the creation of a deep intronic cryptic splice site that leads to an RNA transcript subject nonsense-mediated decay. Several carriers had previously undergone DNA-only genetic testing and had received a negative result.

CONCLUSION

Here, we describe how paired DNA-RNA MGPT can be used to solve missing heritability in FAP families, which can have important implications in family planning and treatment decisions for patients and their families.

Gene-specific ACMG/AMP classification criteria for germline APC variants: Recommendations from the ClinGen InSiGHT Hereditary Colorectal Cancer/Polyposis Variant Curation Expert Panel

PURPOSE

The Hereditary Colorectal Cancer/Polyposis Variant Curation Expert Panel (VCEP) was established by the International Society for Gastrointestinal Hereditary Tumours and the Clinical Genome Resource, who set out to develop recommendations for the interpretation of germline APC variants underlying Familial Adenomatous Polyposis, the most frequent hereditary polyposis syndrome.

METHODS

Through a rigorous process of database analysis, literature review, and expert elicitation, the APC VCEP derived gene-specific modifications to the ACMG/AMP (American College of Medical Genetics and Genomics and Association for Molecular Pathology) variant classification guidelines and validated such criteria through the pilot classification of 58 variants.

RESULTS

The APC-specific criteria represented gene- and disease-informed specifications, including a quantitative approach to allele frequency thresholds, a stepwise decision tool for truncating variants, and semiquantitative evaluations of experimental and clinical data. Using the APC-specific criteria, 47% (27/58) of pilot variants were reclassified including 14 previous variants of uncertain significance (VUS).

CONCLUSION

The APC-specific ACMG/AMP criteria preserved the classification of well-characterized variants on ClinVar while substantially reducing the number of VUS by 56% (14/25). Moving forward, the APC VCEP will continue to interpret prioritized lists of VUS, the results of which will represent the most authoritative variant classification for widespread clinical use.

The Diagnostic Yield of Genetic Testing in Patients With Multiple Colorectal Adenomas: A Specialist Center Cohort Study

INTRODUCTION

Adenoma multiplicity is associated with increased colorectal cancer (CRC) risk. The utility of genetic testing in patients with multiple colorectal adenomas (MCRA) remains uncertain. We evaluated the diagnostic yield of mutations in polyposis- and CRC-associated genes in patients with MCRA.

METHODS

We performed a cross-sectional review of adult patients with 10-99 cumulative adenomas from the prospective database at the St Mark's Hospital Polyposis Registry and Family Cancer Clinic between 1999 and 2021. Genetic testing was performed for adenomatous polyposis-associated genes, hamartomatous polyposis-associated genes, and nonpolyposis colorectal cancer-associated genes. Clinicopathological outcomes were extracted for multiple logistic regression analysis.

RESULTS

Two hundred fifty-nine patients with MCRA (median age 61 [interquartile range 53-69] years) were identified. Sixty-six patients (25.5%) had a pathogenic variant or likely pathogenic variant, with APC and biallelic MUTYH mutations constituting the majority of identified pathogenic variant/likely pathogenic variants. Diagnostic yields were greater than 10% at any adenoma burden. In univariate analysis, higher adenoma burden and younger age were associated with higher yield (both P < 0.0001). In patients with MCRA with 10-19 adenomas without a relevant personal or family history of CRC, the diagnostic yield was nil. In multiple logistic regression analysis, higher adenoma burden, younger age, personal history of CRC, and first-degree familial history of CRC were associated with higher diagnostic yield.

DISCUSSION

Diagnostic yield of >10% at any adenoma burden supports current guidance for constitutional genetic testing in patients with MCRA, although the low yield in people older than 60 years with 10-19 adenomas suggests that a stratified approach might be appropriate.

Diffuse familial adenomatous intestinal polyposis in childhood: current state of the problem and case report

OBJECTIVE

Aim: To explore the prevalence, clinical characteristics, and diagnostic aspects of diffuse familial adenomatous polyposis in childhood. This objective is accomplished through an extensive review of recent literature, and the presentation of case report from our clinical practice.

PATIENTS AND METHODS

Materials and Methods: We analyzed 75 scientific papers, the findings of which have been documented in the PubMed database. Our search criteria included keywords such as ≪diffuse familial adenomatous intestinal polyposis,≫ ≪children,≫ and ≪diagnosis.≫ Then we conducted a second-stage analysis that involved a detailed review of a practical case - the medical records of inpatient Kh.V. who had been diagnosed with familial adenomatous polyposis.

CONCLUSION

Conclusions: The analysis of the literature data is consistent with the findings from our clinical observations of familial adenomatous polyposis in a patient with complicated family anamnesis. It is worth noting that clinical features do not significantly differ across various types of polyposis. In cases of suspected familial adenomatous polyposis in adolescents, genetic testing is crucial.

[Results of Endoscopic Screening and Therapy of the Duodenum in MUTYH-associated Polyposis]

MUTYH-associated polyposis (MAP) is a very rare autosomal recessive polyposis syndrome. It is caused by a homozygous or compound heterozygous germline mutation in the MUTYH gene. MAP is characterised by numerous colorectal adenomas; furthermore there is an increased risk for colorectal cancer (CRC). However, the phenotype can be highly variable; for example, affected individuals also have an increased risk of polyps of the upper gastrointestinal tract and development of duodenal carcinomas.This study included 15 patients with evidence of a pathogenic MUTYH variant, who were screened at the National Center for Hereditary Tumor Syndromes. Oesophagogastroduodenoscopy (EGD) results were prospectively recorded in a database from 2012 to 2023.At least one EGD (median 4, range 1-15) was performed in 15 patients, seven of whom carried a homozygous and 8 a compound heterozygous pathogenic MUTYH variant. The median surveillance period was 115 months (range, 3-215 months). The median age at baseline was 44 (range 17-65) years. A total of 72 EGDs were performed (median 4; range 1-15). Five patients had duodenal adenomas; histology showed tubular adenomas with low grade intraepithelial dysplasia (LGIEN) in all of these cases. The total number of duodenal adenomas detected was 48, and the median number was 3 (range, 1-37). Neither high grade intraepithelial neoplasia (HGIEN) nor duodenal cancer was detected during the surveillance period.Patients with MUTYH-associated polyposis should be managed in a multidisciplinary centre for hereditary tumour disease. Our cohort showed more patients with duodenal adenomas than in previously published data. However, no progression to HGIEN or duodenal carcinomas was observed as a result of the endoscopic therapy performed.

Atypical hypertrophy of retinal pigment epithelium manifesting as the first sign of familial adenomatous polyposis

A female patient in her 20s presented to a routine ophthalmology appointment. Medical history was unremarkable. Family history was notable for intestinal cancer of a second-degree relative, diagnosed in her late 60s. Fundus examination revealed bilateral, multiple, flat, oval, pigmented lesions with an irregular halo of atrophy. The patient was diagnosed with atypical congenital hypertrophy of retinal pigmented epithelium. Investigation of extraocular associations was performed, including upper and lower endoscopy, which revealed 500-1000 colonic polyps with a maximum size 25 mm. Pathology did not reveal submucosal invasion. Genetic testing detected an adenomatous polyposis coli mutation (heterozygotic variant c.3183_3187delACAAA p.(Gln1062*)).

A one-stop approach to diagnosing hereditary colorectal cancer in the Chinese population

BACKGROUND AND AIM

The current procedure for identifying hereditary colorectal cancer (HCRC) is time consuming in clinical practice. This study aimed to develop a time-saving approach to diagnosing HCRC.

METHODS

A total of 100 suspected HCRC patients were prospectively enrolled (cohort 1) and 116 colorectal cancer patients with DNA mismatch repair-deficient were retrospectively included (cohort 2). Next-generation sequencing (NGS) tests were performed on tumors and matched white blood cells (WBCs) or normal tissues. Using the conventional method upon WBC/normal tissue-based NGS data as a reference, the performance of the ColonCore method using tumor-only-based NGS data in predicting germline variants was explored in cohort 1 and validated in cohort 2.

RESULTS

In cohort 1, the ColonCore method diagnosed 17 Lynch syndrome (LS) and 14 familial adenomatous polyposis (FAP); and by the conventional method, the cases were 16 and 10, respectively. The ColonCore method showed sensitivities of 100% in diagnosing LS (positive predictive value [PPV] 94.1%) and FAP (PPV 71.4%). Moreover, two of seven patients with multiple adenomas/polyps who did not meet existing clinical criteria for HCRC were predicted to harbor germline variants in APC and MUTYH. Additionally, the sensitivity of the ColonCore method in identifying LS patients from cohort 2 reached 85.7% with a PPV of 85.7%.

CONCLUSION

The ColonCore method might be an acceptable tool for predicting germline variants associated with HCRC. Our work indicates the essentiality of NGS tests in CRC patients for precision diagnosis and treatment.

Two Cases, Too Little, Too Late: Surveillance for Gastric Cancer in Patients with FAP

Familial adenomatous polyposis is an autosomal dominant disease due to a mutation in the adenomatous polyposis coli (APC) gene. The disease, characterized by the development of adenomas throughout the colon and rectum, is also associated with extracolonic manifestations including gastric fundic polyps and cancer. In this report, we describe two patients with FAP with advanced gastric adenocarcinoma who received systemic chemotherapy. We reviewed the literature published over the past two decades on gastric cancer in FAP patients to assess the clinical course of this disease. Due to its recent increased incidence in Western countries, close endoscopic surveillance to detect early gastric neoplastic lesions is recommended.

Recommendations for the classification of germline variants in the exonuclease domain of POLE and POLD1

BACKGROUND

Germline variants affecting the proofreading activity of polymerases epsilon and delta cause a hereditary cancer and adenomatous polyposis syndrome characterized by tumors with a high mutational burden and a specific mutational spectrum. In addition to the implementation of multiple pieces of evidence for the classification of gene variants, POLE and POLD1 variant classification is particularly challenging given that non-disruptive variants affecting the proofreading activity of the corresponding polymerase are the ones associated with cancer. In response to an evident need in the field, we have developed gene-specific variant classification recommendations, based on the ACMG/AMP (American College of Medical Genetics and Genomics/Association for Molecular Pathology) criteria, for the assessment of non-disruptive variants located in the sequence coding for the exonuclease domain of the polymerases.

METHODS

A training set of 23 variants considered pathogenic or benign was used to define the usability and strength of the ACMG/AMP criteria. Population frequencies, computational predictions, co-segregation data, phenotypic and tumor data, and functional results, among other features, were considered.

RESULTS

Gene-specific variant classification recommendations for non-disruptive variants located in the exonuclease domain of POLE and POLD1 were defined. The resulting recommendations were applied to 128 exonuclease domain variants reported in the literature and/or public databases. A total of 17 variants were classified as pathogenic or likely pathogenic, and 17 as benign or likely benign.

CONCLUSIONS

Our recommendations, with room for improvement in the coming years as more information become available on carrier families, tumor molecular characteristics and functional assays, are intended to serve the clinical and scientific communities and help improve diagnostic performance, avoiding variant misclassifications.

Preventive strategies in familial and hereditary colorectal cancer

Colorectal cancer is a leading cause of cancer-related deaths worldwide. While most cases are sporadic, a significant proportion of cases are associated with familial and hereditary syndromes. Individuals with a family history of colorectal cancer have an increased risk of developing the disease, and those with hereditary syndromes such as Lynch syndrome or familial adenomatous polyposis have a significantly higher risk. In these populations, preventive strategies are critical for reducing the incidence and mortality of colorectal cancer. This review provides an overview of current preventive strategies for individuals at increased risk of colorectal cancer due to familial or hereditary factors. The manuscript includes a discussion of risk assessment and genetic testing, highlighting the importance of identifying at-risk individuals and families. This review describes various preventive measures, including surveillance colonoscopy, chemoprevention, and prophylactic surgery, and their respective benefits and limitations. Together, this work highlights the importance of preventive strategies in familial and hereditary colorectal cancer.

NTHL1 Gene Mutations in Polish Polyposis Patients-Weighty Player or Vague Background?

Multiple polyposes are heterogeneous diseases with different underlying molecular backgrounds, sharing a common symptom: the presence of transforming into cancerous intestinal polyps. Recent reports have indicated biallelic mutations in the NTHL1 gene, which is involved in base excision repair (BER), as predisposing to an elevated risk of colorectal cancer (CRC). We aimed to evaluate the significance of the p.Q82* truncating variant in predisposition to intestinal polyposis by assessing its frequency in polyposis patients. We genotyped 644 Polish patients and 634 control DNA samples using high-resolution melting analysis (HRM) and Sanger sequencing. We found the p.Q82* variant in four polyposis patients; in three, it was homozygous (OR = 6.90, p value = 0.202). Moreover, the p.R92C mutation was detected in one patient. We also looked more closely at the disease course in patients carrying NTHL1 mutations. Two homozygous patients also presented other neoplasia. In the family case, we noticed the earlier presence of polyps in the proband and early hepatoblastoma in his brother. We cannot univocally confirm the relationship of p.Q82* with an increased risk of CRC. However, homozygous p.Q82* was more frequent by 10-fold in patients without other mutations identified, which makes NTHL1 gene screening in this group reasonable.

Attenuated Familial Adenomatous Polyposis

A 36-year-old man was diagnosed with multiple gastric polyps by esophagogastroduodenoscopy. Subsequent colonoscopy identified two tubular adenomas, and computed tomography revealed subcutaneous tumors. Based on these findings, we suspected that gastric polyposis was associated with the APC gene, either attenuated familial adenomatous polyposis (AFAP) or gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). A genetic analysis demonstrated that he had a frameshift variant at codon 1928 of APC, suggesting AFAP. In this era of less Helicobacter pylori infection and frequent use of proton pump inhibitors, diagnoses of AFAP and GAPPS should be considered in patients with prominent gastric fundic gland polyposis.

An update of the variant spectrum of the APC gene in Iranian familial adenomatous polyposis patients

Familial adenomatous polyposis (FAP) is an autosomal dominant colorectal cancer syndrome that is characterized by the development of multiple adenomas in the colon and rectum with high penetrance rates. This disease has specific features like the occurrence of pathogenic variations in the APC gene and diverse FAP phenotypes due to the occurrence region. In this study we aimed to evaluate pathogenic variants in exons of the APC gene in Iranian patients with FAP. A total of 35 FAP individuals were referred to the gastroenterology ward of Taleghani Hospital. As the aim of the study was to study the germline variations in the participants, the peripheral blood was collected and after the DNA extraction, PCR, and Sanger sequencing processes for the APC gene, the results were evaluated by the ACMG classification guidelines to report their pathogenicity. Accordingly, out of eight specific detected variants, three of them were novel, and the rest were reported previously. These eight variants were all truncating protein and pathogenic, and they were limited to 849-1378 codons. Overall, detected variants revealed discrepancies and parallels with previous reported cases in terms of quantity, occurrence region, and association with demographic and clinicopathological characteristics of patients. The spectrum of detected variants and the patient's phenotype showed distinct characteristics, such as occurrence in specific regions and the absence of extracolonic symptoms like Congenital hypertrophy of the retinal pigment epithelium (CHRPE). These findings open the path to comprehending the typical symptoms, their rarity, and their occurrence in the Iranian population and also due to the facts, we found that the studying of the APC gene alone for diagnosing FAP disease is not sufficient, and considering other genes are completely rational in the case of sequencing and studying the variants.

Primary and Secondary Prevention Interventions to Reduce Risk Factors Associated with Colorectal Cancer in High-Risk Groups: a Systematic Literature Review

In the USA, colorectal cancer (CRC) is the 2nd leading cause of cancer-related deaths. Certain groups in the USA are at an increased risk of developing CRC, including those with a genetic risk and family history. The purpose of this project was to synthesize primary and secondary prevention interventions for individuals who are at high risk of CRC due to family history or genetic predisposition. This study systematically reviewed articles from PubMed, Google Scholar, and EBSCO using specific search terms to find relevant articles. Sixteen articles were identified for full-text review, which were categorized as non-drug interventions (n = 7) and drug interventions (n = 9). Non-drug interventions focused primarily on increasing screening in those with a first-degree relative (FDR) with CRC or those with Lynch syndrome (LS). Interventions that increased CRC screening often had a tailored component and were otherwise varied in study designs and intervention type. Drug interventions focused on the use of NSAIDs on patients with familial adenomatous polyposis (FAP). Studies showed very little racial and ethnic diversity. Findings suggest that tailored interventions are particularly effective in increasing CRC screening, and greater diversity of sample is needed with respect to race and ethnicity.

Laboratory variation in the grading of dysplasia of duodenal adenomas in familial adenomatous polyposis patients

To prevent duodenal and ampullary cancer in familial adenomatous polyposis (FAP) patients, a diagnosis of high grade dysplasia (HGD) plays an important role in the clinical management. Previous research showed that FAP patients are both over- and undertreated after a misdiagnosis of HGD, indicating unwarranted variation. We aimed to investigate the laboratory variation in dysplasia grading of duodenal adenomas and explore possible explanations for this variation. We included data from all Dutch pathology laboratories between 1991 and 2020 by retrieving histology reports from upper endoscopy specimens of FAP patients from the Dutch nationwide pathology databank (PALGA). Laboratory variation was investigated by comparing standardized proportions of HGD. To describe the degree of variation between the laboratories a factor score was calculated. A funnel plot was used to identify outliers. A total of 3050 specimens from 25 laboratories were included in the final analyses. The mean observed HGD proportion was 9.4%. The top three HGD-diagnosing laboratories diagnosed HGD 3.9 times more often than the lowest three laboratories, even after correcting for case-mix. No outliers were identified. Moderate laboratory variation was found in HGD diagnoses of duodenal tissue of FAP patients after adjusting for case-mix. Despite the fact that no outliers were observed, there may well be room for quality improvement. Concentration of these patients in expertise centers may decrease variation. To further reduce unwarranted variation, we recommend (inter)national guidelines to become more uniform in their recommendations regarding duodenal tissue sampling and consequences of HGD diagnoses.

Six case reports of NTHL1-associated tumor syndrome further support it as a multi-tumor predisposition syndrome

NTHL1-associated tumor syndrome (NATS) is an autosomal recessive condition characterized by an increased risk for colorectal polyposis and colorectal cancer (CRC). Only 46 case reports have been previously published. In a retrospective review, we analyzed the clinical histories of six patients found to have NATS after genetic counseling and testing. NATS appears to be associated with an increased risk for colorectal polyposis, CRC, female breast cancer, meningiomas, and endometrial cancer. Although research is limited, prior publications have reported a multi-tumor predisposition for individuals with biallelic pathogenic or likely pathogenic variants in NTHL1. Additional data are necessary to further define the cancer risks so affected individuals can be appropriately managed.

A large family with MSH3-related polyposis

Biallelic MSH3 germline variants are a rare cause of adenomatous polyposis as yet reported in two small families only. We describe the phenotype of a third family, the largest thus far, with adenomatous polyposis related to compound heterozygous MSH3 pathogenic variants. The index patient was a 55-years old male diagnosed with rectal cancer and adenomatous polyposis (cumulatively 52 polyps), with a family history of colorectal polyposis with unknown cause. Next-generation sequencing and copy number variation analysis of a panel of genes associated with colorectal cancer and polyposis revealed compound heterozygous germline pathogenic variants in the MSH3 gene. Nine out of 11 siblings were genotyped. Three siblings carried the same compound heterozygous MSH3 variants. Colonoscopy screening showed predominantly right-sided adenomatous polyposis in all compound heterozygous siblings, with a cumulative number of adenomas ranging from 18 to 54 in an average of four colonoscopies, and age at first adenoma detection ranging from 46 to 59. Microsatellite analysis demonstrated alterations at selected tetranucleotide repeats (EMAST) in DNA retrieved from the rectal adenocarcinoma, colorectal adenomas as well as of normal colonic mucosa. Gastro-duodenoscopy did not reveal adenomas in any of the four patients. Extra-intestinal findings included a ductal adenocarcinoma in ectopic breast tissue in one female sibling at the age of 46, and liver cysts in three affected siblings. None of the three heterozygous or wild type siblings who previously underwent colonoscopy had adenomatous polyposis. We conclude that biallelic variants in MSH3 are a rare cause of attenuated adenomatous polyposis with an onset in middle age.

Clinical features and long-term outcomes of patients with colonic oligopolyposis of unknown etiology

BACKGROUND

Colonic adenomatous polyposis of unknown etiology (CPUE) is an adenomatous polyposis phenotype that resembles Familial Adenomatous Polyposis (FAP) even though no germline pathogenic variant is identified.

AIM

We sought to better characterize the clinical features and outcomes in a cohort of CPUE patients.

METHODS

This is a retrospective case series of patients 18 years old or older with aden-omatous oligopolyposis (between 10-100 adenomas) and negative genetic testing, identified through the Hereditary Gastrointestinal Cancer Database at Massachusetts General Hospital, a tertiary academic referral center. A retrospective chart review was performed with a focus on demographics, alcohol and tobacco use, medication use, familial malignancy and polyp burden, genetic testing information, endoscopic surveillance data including the corresponding histopathology, colonic and extracolonic malignancies, mortality events, and their etiology. Spearman correlation and Pearson Chi-square test (or Fisher's exact test) were used for continuous and categorical variables respectively.

RESULTS

CPUE patients were primarily male (69%) and presented for genetic counseling at 63.7 years. Only 2 patients (2.9%) reported a first-degree relative with polyposis. During an average surveillance period of 12.3 years, 0.5 colonoscopies per year were performed. Patients developed 2.3 new adenomas per year. 4 (5.7%) were diagnosed with colorectal cancer (CRC) at a mean age of 66 years, and 3 were diagnosed prior to the onset of oligopolyposis. 7 (10%) required colectomy due to advanced dysplasia or polyp burden. With respect to upper gastrointestinal manifestations, 1 patient had a gastric adenoma, but there were no cases of gastric or small bowel polyposis. During surveillance, 10 (14%) patients died at a mean age of 72, and none were due to CRC.

CONCLUSION

CPUE is distinct from familial adenomatous polyposis (FAP) syndrome and the use of FAP surveillance guidelines may result in unnecessarily frequent upper and lower endoscopies.

RETINAL PIGMENT EPITHELIAL LESIONS ASSOCIATED WITH A SPORADIC CASE OF FAMILIAL ADENOMATOUS POLYPOSIS

PURPOSE

To report a sporadic case of a familial adenomatous polyposis (FAP) discovered in a patient with bilateral retinal pigment epithelial lesions.

METHODS

Case report.

RESULTS

A 30-year-old Asian woman presented for evaluation of bilateral pigmented lesions at the level of the retinal pigment epithelium. She had no personal or family history of colonic polyps or colon cancer. Colonoscopy revealed innumerable adenomatous polyps and genetic testing revealed a mutation in the adenomatous polyposis coli gene consistent with FAP. She subsequently underwent prophylactic total colectomy.

CONCLUSION

The pigmented retinal pigment epithelium lesions of FAP have a characteristic appearance and it is vital for the retinal specialist to be familiar with them. De novo mutations in the APC gene are responsible for 20% to 30% of FAP cases. In the presence of the characteristic retinal pigment epithelium lesions, it is important to send the patient for work up of FAP even in the absence of family history of FAP.

Study of diagnostic value of congenital hypertrophy of retinal pigment epithelium in Chinese familial adenomatous polyposis patients

BACKGROUND

Congenital hypertrophy of retinal pigment epithelium (CHRPE) is an important characteristic of familial adenomatous polyposis (FAP) patients. However, more evidence about its sensitivity, specificity, and diagnostic value for FAP is needed to determine whether CHRPE is a reliable marker.

METHODS

Clinical features of FAP patients were investigated using in-person evaluations. Family members of FAP patients were evaluated with an indirect ophthalmoscope to determine whether they had CHRPE. We defined three diagnostic criteria for CHRPE (criteria A, B and C) based on their shape, quantity and size. Those with negative colonoscopy results and gene mutation results were classified as healthy controls.

RESULTS

Of a total of 23 FAP families, 21 families were CHRPE-positive (91.3%). Among those 21 families, 47 individuals had CHRPE, including 33 FAP patients, 9 APC gene mutation carriers, and 5 individuals younger than 18 years who were later confirmed to have FAP. Fifty individuals had no CHRPE (5 FAP patients and 45 individuals without APC gene mutations and colorectal adenoma). The average number of CHRPE lesions per person was 5.81, and CHRPE was located mostly in the posterior pole in the eye fundus; 76.7% of individuals had CHRPE in both eyes. The sensitivity of the three CHRPE criteria ranged from 78.8 to 90.4%, with the highest sensitivity found for criterion A (90.4%), which had a specificity of 100% for healthy controls and sporadic colorectal cancer patients.

CONCLUSION

CHRPE has vital diagnostic and screening value because of its high sensitivity for discovering FAP and APC gene mutation carriers.

Continuing Medical Education Questions: June 2022

Article Title: Diagnosis and Management of Cancer Risk in the Gastrointestinal Hamartomatous Polyposis Syndromes: Recommendations From the US Multi-Society Task Force on Colorectal Cancer.

Attenuated Familial Adenomatous Polyposis: A Phenotypic Diagnosis but Obsolete Term?

BACKGROUND

Attenuated familial adenomatous polyposis is characterised by low number (≤100) and delayed development of colorectal adenomas. Various definitions have been used, and genotype-phenotype correlations have been suggested.

OBJECTIVE

We aimed to evaluate phenotypic and genotypic correlation in patients with presumed attenuated familial adenomatous polyposis and assess familial variability.

DESIGN

This is a retrospective study.

SETTINGS

This study was conducted at a tertiary polyposis registry.

PATIENTS

Individuals with attenuated familial adenomatous polyposis were identified. Phenotypic group was defined as 100 or fewer adenomas at age 25 years and genotypic group was defined as a variant in the adenomatous polyposis coli region associated with attenuated familial adenomatous polyposis. Pathology polyp count was used for patients who had undergone surgery and endoscopic polyp count for those with intact colon.

MAIN OUTCOME MEASURES

We evaluated phenotypic and genotypic correlation in patients with presumed attenuated familial adenomatous polyposis and familial variability.

RESULTS

A total of 69 patients were identified in the phenotypic group, of whom 54 (78%) had a pathogenic variant in the attenuated regions of the adenomatous polyposis coli gene. Forty-eight (70%) had intact colon (median age at last colonoscopy 43 [25-73] years; median endoscopic polyp count 20 [0-100]) and 21 (30%) had undergone colectomy (median age at surgery 45 [25-54] years; median pathology polyp count 43 [3-100]). Eighty-three patients were identified in the genotypic group of which 54 (65%) had attenuated phenotype. Inter- and intrafamilial variability were observed.

LIMITATIONS

This study was limited by its retrospective nature and single-center experience.

CONCLUSION

Phenotype in familial adenomatous polyposis lies on a spectrum and is determined in part by genotype and age at adenoma count. Diagnosis of attenuated familial adenomatous polyposis should be based on phenotype; genotype is not a reliable indicator. Management should be personalized according to the phenotype of each individual. See Video Abstract at http://links.lww.com/DCR/B775.

POLIPOSIS ADENOMATOSA FAMILIAR ATENUADA UN DIAGNSTICO FENOTPICO PERO TRMINO OBSOLETO

ANTECEDENTES:La poliposis adenomatosa familiar atenuada se caracteriza por un número bajo (≤100) y desarrollo retardado de adenomas colorrectales. Se han utilizado varias definiciones y se han sugerido correlaciones genotipo-fenotipo.OBJETIVO:Nuestro objetivo es evaluar la correlación fenotípica y genotípica en pacientes con presunta poliposis adenomatosa familiar atenuada y evaluar la variabilidad familiar.DISEÑO:Este es un estudio retrospectivo.AJUSTE:Este estudio se realizó en un registro terciario de poliposis.PACIENTES:Se identificaron individuos con poliposis adenomatosa familiar atenuada. El grupo fenotípico se definió como ≤100 adenomas a la edad de 25 años y el grupo genotípico se definió como una variante en la región de poliposis coli adenomatosa asociada con poliposis adenomatosa familiar atenuada. Se utilizó el recuento de pólipos en patología para los pacientes que se habían sometido a cirugía y el recuento de pólipos endoscópico para los que tenían el colon intacto.PRINCIPALES MEDIDAS DE RESULTADO:Evaluamos la correlación fenotípica y genotípica en pacientes con presunta poliposis adenomatosa familiar atenuada y variabilidad familiar.RESULTADOS:Un total de 69 pacientes se identificaron en el grupo fenotípico de los cuales 54 (78%) tenían una variante patogénica en las regiones atenuadas del gen de la poliposis coli adenomatosa. Cuarenta y ocho (70%) tenían colon intacto (edad media en la última colonoscopia 43 [25-73] años; mediana del recuento de pólipos endoscópicos 20 [0-100]) y 21 (30%) se habían sometido a colectomía (edad edia en el momento de la cirugía 45 [25-54] años; mediana del recuento de pólipos patológicos 43 [3-100]). Se identificaron 83 pacientes en el grupo genotípico de los cuales 54 (65%) tenían fenotipo atenuado. Se observó variabilidad inter e intrafamiliar.LIMITACIONES:Este estudio estuvo limitado por su naturaleza retrospectiva y la experiencia de un solo centro.CONCLUSIÓNES:El fenotipo en la poliposis adenomatosa familiar se encuentra en un espectro, determinado en parte por el genotipo y la edad en el momento del recuento de adenomas. El diagnóstico de poliposis adenomatosa familiar atenuada debe basarse en el fenotipo; el genotipo no es un indicador confiable. El manejo debe personalizarse según el fenotipo de cada individuo. Consulte Video Resumen en http://links.lww.com/DCR/B775.

Risk of Colorectal Cancer in Serrated Polyposis Syndrome: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Serrated polyposis syndrome (SPS) is characterized by development of numerous serrated lesions throughout the colorectum and increased risk of colorectal cancer (CRC). However, SPS has been an underrecognized CRC predisposition syndrome, and the true risk of CRC in SPS, both overall and in surveillance, is not known. The aim of this systematic review and meta-analysis is to describe the risk of CRC in patients with SPS.

METHODS

Electronic databases were searched on March 25, 2021, for studies describing CRC risk in SPS. Random-effects meta-analysis was performed to assess pooled risk of CRC among SPS patients. Primary outcomes were risk of CRC at time of SPS diagnosis and during surveillance following diagnosis of SPS. Secondary outcomes included risk of CRC prior to diagnosis of SPS and effect of World Health Organization subtype on CRC risk.

RESULTS

Thirty-six studies including 2788 patients with SPS were included in the analysis. Overall risk of CRC in SPS was 19.9% (95% confidence interval [CI], 15.3%-24.5%). CRC risk at the time of diagnosis was 14.7% (95% CI, 11.4%-18.8%), while risk during surveillance was 2.8% (95% CI, 1.8%-4.4%), or 7 cases per 1000 person-years. SPS patients also had a high incidence of history of CRC prior to SPS diagnosis (7.0%; 95% CI, 4.6%-11.7). Subgroup analysis did not reveal any significant differences based on World Health Organization subtype.

CONCLUSIONS

Our meta-analysis demonstrated that patients with SPS have an elevated risk of CRC, which is highest at the time of diagnosis and suggests the importance of early SPS recognition and screening to modify CRC risk. The persistently elevated CRC risk during surveillance supports current guidelines recommending heightened surveillance protocols.

SULT1A1 and SULT1A2 Associated Extensive Prolapse-Type Inflammatory Polyposis in Crohn's Colitis

Mucosal prolapse syndrome most commonly involves the rectum and presents as solitary rectal ulcer syndrome and proctitis cystica profunda. Symptoms and endoscopic appearances are nonspecific. Histologically, mucosal prolapse is characterized by fibromuscular obliteration of the lamina propria, and displacement of crypts into submucosa and muscularis mucosae. Mucosal prolapse presenting as polyposis is rare and has only been reported involving the rectosigmoid colon. In this report, we describe a case of mucosal prolapse syndrome presenting as diffuse polyposis and colitis cystica profunda involving the hepatic, splenic flexures and descending colon in a teenage boy suffering from refractory fibrostenosing Crohn's disease. This patient was found to have possibly deleterious homozygous single nucleotide polymorphisms in both SULT1A1 and SULT1A2 genes within a unique polygenic variation of altered cell adhesion.

Paediatric polyposis syndromes: burden of disease and current concepts

PURPOSE OF REVIEW

Polyposis syndromes are rare but significant entities that often present during childhood and adolescence. Polyposis syndromes should remain high on the differential diagnoses for any child presenting with rectal bleeding, protein-losing enteropathy or intussusception in the setting of multiple polyps in the gastrointestinal tract. There are three primary paediatric polyposis syndromes: Juvenile polyposis syndrome (JPS), Familial adenomatous polyposis (FAP) and Peutz-Jeghers syndrome (PJS). This review will cover recent guidelines for these conditions and advances in genetic testing.

RECENT FINDINGS

The first set of paediatric guidelines were released in 2019 by the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) for FAP, JPS and PJS. Even with advances in genetic testing, a significant proportion of patients with polyposis syndromes have no identifiable genetic mutations. Recent research has shown that polyps behave differently in patients with and without disease-causing variants, emphasizing the role of genetic testing in the diagnosis and management of polyposis syndromes.

SUMMARY

Polyposis syndromes in the paediatric population are growing due to increased recognition and advances in genetic testing. A timely diagnosis and surveillance of a paediatric polyposis syndrome are pivotal for the management of disease burden and early identification of cancers within the gastrointestinal tract and beyond. Paediatricians, paediatric gastroenterologists, paediatric oncologists and paediatric surgeons should be familiar with the presentation and comorbidities of polyposis syndromes in children and adolescents. Further research into genotype-phenotype correlations is needed to tailor the care for paediatric patients with polyposis syndromes.

Diagnosis and classification of ileal pouch disorders: consensus guidelines from the International Ileal Pouch Consortium

Restorative proctocolectomy with ileal pouch-anal anastomosis is an option for most patients with ulcerative colitis or familial adenomatous polyposis who require colectomy. Although the construction of an ileal pouch substantially improves patients' health-related quality of life, the surgery is, directly or indirectly, associated with various structural, inflammatory, and functional adverse sequelae. Furthermore, the surgical procedure does not completely abolish the risk for neoplasia. Patients with ileal pouches often present with extraintestinal, systemic inflammatory conditions. The International Ileal Pouch Consortium was established to create this consensus document on the diagnosis and classification of ileal pouch disorders using available evidence and the panellists' expertise. In a given individual, the condition of the pouch can change over time. Therefore, close monitoring of the activity and progression of the disease is essential to make accurate modifications in the diagnosis and classification in a timely manner.

Malignancy risk in individuals with familial adenomatous polyposis receiving biologics and immunomodulators

Clinicians may be hesitant to prescribe biologics or immunomodulators to individuals with familial adenomatous polyposis (FAP) and comorbid inflammatory disease (CID) because of increased cancer risk. Our aim was to compare the risk of malignancy in FAP individuals with inflammatory bowel (IBD) and/or rheumatic disease that received biologics/immunomodulators to those who did not. Individuals with FAP and CID were included in the study. We compared the incidence of cancer between individuals exposed to biologics/immunomodulators compared to unexposed from the date of diagnosis of comorbid disease till last follow up or death. Hazard ratio (HR) for cancer was computed using Cox regression model and compared by exposure status to biologic/immunomodulators. 25 individuals with FAP and a comorbid inflammatory disease were identified including 9 (36%) with IBD and 16 (64%) with rheumatic disease. 14 (56%) were exposed to a biologic and or immunomodulator. Median duration of biologic/immunomodulator exposure was 48 (2-180) months. 3 (21.4%) in the exposed group compared to 1 (9.1%) in the unexposed group developed cancer with a HR for exposure of 1.92 (CI 0.2-18.5, p = 0.57). Median duration of follow up after the diagnosis of inflammatory disease was 10 (5.5-17.0) years in the exposed and 6 (3.0-15.0) years in the unexposed group. In the exposed group, 1 patient developed gastric and 2 developed colon cancer. One unexposed patient developed medullary thyroid cancer. There is a possible trend of more cancers in the group that received biologics/immunomodulators-but given the small number of patients and p-value, there may be no difference at all. This preliminary finding warrants study in a larger cohort.

Definition and management of colorectal polyposis not associated with APC/MUTYH germline pathogenic variants: AIFEG consensus statement

An expert consensus panel convened by the Italian Association for Inherited and Familial Gastrointestinal Tumors (Associazione Italiana per lo Studio della Familiarità ed Ereditarietà dei Tumori Gastrointestinali, AIFEG) reviewed the literature and agreed on a number of position statements regarding the definition and management of polyposis coli without an identified pathogenic mutation on the APC or MUTYH genes, defined in the document as NAMP (non-APC/MUTYH polyposis).

Pigmented Ocular Fundus Lesions Associated With Familial Adenomatous Polyposis

A 36-year-old man was referred for evaluation after trauma to the left eye. He gave a history of familial adenomatous polyposis (FAP) diagnosed at age 15 years and treated with prophylactic colectomy. Funduscopy revealed multifocal pigmented ocular fundus lesions at the level of the retinal pigment epithelium (RPE) in both eyes (Figure 1A and 1B). The lesions were haphazardly distributed, oval-shaped, variable in size, and with irregular borders. On fundus autofluorescence, the RPE lesions were hypoautofluorescent and surrounded by trace hyperautofluorescence (Figure 1C and 1D). These findings represented the pigmented ocular fundus lesions that serve as a biomarker for FAP. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:124.].

Clinical application of next-generation sequencing for the management of desmoid tumors: A case report and literature review

RATIONALE

Desmoid tumors are rare myofibroblastic neoplasms characterized by local invasiveness and high rates of recurrence, and sometimes mimic local recurrence of previously resected malignancies. Previous studies have suggested that molecular profiling may be useful for the diagnosis of the tumors and risk stratification. However, the clinical utility of next-generation sequencing (NGS) for the management of desmoid tumors has not been established.

PATIENT CONCERNS

A 42-year-old man visited our clinic for routine follow-up 1 year after left upper lobe lingular segmentectomy for lung adenocarcinoma.

DIAGNOSES

Chest computed tomography showed a pleural mass adherent to the thoracotomy site. Positron emission tomography revealed mildly increased metabolism with a maximal standardized uptake value of 2.7 within the tumor, suggesting local recurrence of the previous neoplasm. Exploratory thoracotomy and en bloc resection of the tumor revealed spindle cells in a massive collagenous tissue consistent with a desmoid tumor.

INTERVENTIONS

NGS was performed to confirm the diagnosis and to identify any genetic alterations that might be relevant to the prognosis of this tumor. The tumor harbored an S45F mutation in CTNNB1, which has been correlated with a high recurrence rate. Therefore, we performed adjuvant radiotherapy on the resection bed at a dose of 56 Gy.

OUTCOMES

The patients experienced no postoperative or radiotherapy-related complications. Periodic follow-up examinations using computed tomography were performed every 3 months, and no evidence of recurrence of either tumor was observed during the 38 months after the last surgery.

LESSONS

To the best of our knowledge, this is the first case reporting the clinical application of NGS and aggressive treatment based on the genotyping results for the management of a desmoid tumor. Our case highlights the need to consider desmoid tumors among the differential diagnoses when a pleural mass is encountered at a previous thoracotomy site. More importantly, molecular profiling using NGS can be useful for the establishment of a treatment strategy for this tumor, although further investigations are required.

Candidate Gene Discovery in Hereditary Colorectal Cancer and Polyposis Syndromes-Considerations for Future Studies

To discover novel high-penetrant risk loci for hereditary colorectal cancer (hCRC) and polyposis syndromes many whole-exome and whole-genome sequencing (WES/WGS) studies have been performed. Remarkably, these studies resulted in only a few novel high-penetrant risk genes. Given this observation, the possibility and strategy to identify high-penetrant risk genes for hCRC and polyposis needs reconsideration. Therefore, we reviewed the study design of WES/WGS-based hCRC and polyposis gene discovery studies (n = 37) and provide recommendations to optimize discovery and validation strategies. The group of genetically unresolved patients is phenotypically heterogeneous, and likely composed of distinct molecular subtypes. This knowledge advocates for the screening of a homogeneous, stringently preselected discovery cohort and obtaining multi-level evidence for variant pathogenicity. This evidence can be collected by characterizing the molecular landscape of tumors from individuals with the same affected gene or by functional validation in cell-based models. Together, the combined approach of a phenotype-driven, tumor-based candidate gene search might elucidate the potential contribution of novel genetic predispositions in genetically unresolved hCRC and polyposis.

Genetic testing in families with hereditary colorectal cancer in British Columbia and Yukon: a retrospective cross-sectional analysis

BACKGROUND

Genetic testing in families with hereditary cancer enables identification of people most likely to benefit from intensive screening and preventive measures; however, the uptake of testing in relatives (known as cascade carrier testing) for hereditary colorectal cancer syndromes has been shown to be low. Our objective was to report rates of familial testing for hereditary colorectal cancer syndromes in a publicly funded hereditary cancer clinic in Canada.

METHODS

A cross-sectional retrospective database review was used to determine testing uptake between 1997 and 2016 for families served by the provincial Hereditary Cancer Program for British Columbia and Yukon. Analyses were conducted for genes associated with syndromes with an increased risk for colorectal cancer, including Lynch syndrome (MLH1, MSH2, MSH6, PMS2 and EPCAM) and familial adenomatous polyposis (APC), and for additional moderate- to high-penetrance genes (STK11, TP53, SMAD4, MUTYH, PTEN and CHEK2). Descriptive statistics were used and all analyses were 2-tailed.

RESULTS

The study cohort included 245 index patients, with carrier testing performed in 382 relatives. The mean age at family member testing was 41.2 years, and most (61.0%) of the family members who underwent testing were women. The median time between disclosure of index cases and their family member's results was 8.3 months. Among eligible first-degree relatives, 32.6% (268/821) underwent testing in BC. Of 67 cancer diagnoses in family members, most (62.7%) occurred before genetic testing.

INTERPRETATION

A substantial proportion of people at risk for hereditary colorectal cancer do not undergo genetic testing. This gap highlights the need to explore barriers to testing and to consider interventions to promote uptake; more aggressive efforts by hereditary cancer programs are needed to reach this highest risk population.

Not all pediatric intestinal polyps are alike

BACKGROUND/AIMS

In childhood, clinical presentation of intes- tinal polyps is variable. Painless rectal red blood loss is the most common presenting sign. Most polyps are sporadic, isolated and benign. However, it is important to correctly identify exceptions. Rare inherited polyposis syndromes need to be recognized because of their increased risk of intestinal and extra-intestinal malignancies. Furthermore, a correct diagnosis and treatment of rare gastro-intestinal malignancies is crucial.

METHODS

Between 2016 and 2018 we encountered 4 different types of intestinal polyps. A database search was performed and patient files were checked for clinical manifestations and histo- pathology. Literature was searched to recapitulate red flags for these syndromes, probability of underlying genetic disorders and diagnostic criteria.

RESULTS

Between 2016 and 2018, 28 patients presented at the Ghent University Hospital with 30 juvenile polyps. Furthermore, we diagnosed juvenile polyposis syndrome, Li Fraumeni syndrome and familial adenomatous polyposis (FAP) in 1 patient each, whilst 2 FAP patients were in follow-up. Each of these diagnoses has a different lifetime risk of (extra)-intestinal malignancy and requires a different approach and follow-up. Histopathology and genetic testing play an important role in identifying these syndromes in pediatric patients.

CONCLUSION

Although most intestinal polyps in childhood are benign juvenile polyps that require no follow-up, rare inherited syndromes should be considered and correctly diagnosed since adequate follow-up is necessary to reduce morbidity and mortality from both gastrointestinal and extraintestinal complications and malignancies.

Surveillance recommendations for patients with Lynch syndrome and FAP : a monocentric study

BACKGROUND AND STUDY AIMS

The most important causes of hereditary colorectal cancer are Lynch syndrome (LS) and the adenomatous polyposis syndromes (familial adenomatous poly- posis syndrome or FAP, attenuated FAP or AFAP and MUTYH associated polyposis syndrome or MAP). The aim of this study was to investigate whether all patients with a hereditary syndrome within one center receive uniform advice regarding surveillance and treatment.

PATIENTS AND METHODS

A retrospective analysis was performed of all electronic patient health records of patients with LS, FAP, AFAP and MAP who received genetic counselling or were followed by a health care specialist at the University Hospital in Ghent.

RESULTS

Data from 122 patients were collected. For all patients, recommendations from the medical genetics department were highly consistent. Adherence to their recommendations was good within the center for the management of colon polyps. There was a lack of consistency in the screening and surveillance advice for other tumors in departments other than gastroenterology. Only 33 patients had systematic follow-up consultations to check results and organize surveillance.

CONCLUSION

Previously, small studies have suggested that patients with hereditary gastrointestinal cancer syndromes infrequently have surveillance as specified in the guidelines. This study shows almost uniform recommendations and good adherence for surveillance of the colon, but incomplete or contradictory advice for surveillance of other organs. The need for an integrated approach from a multidisciplinary team will only increase in the future, because more families with hereditary cancer are likely to be found due to the increased use of next generation sequencing in cancer diagnostics.

Multifocality in a Patient with Cribriform-Morular Variant of Papillary Thyroid Carcinoma Is an Important Clue for the Diagnosis of Familial Adenomatous Polyposis

Background: Cribriform-morular variant of papillary thyroid carcinoma (CMV-PTC) is a rare subtype of PTC, which occurrs predominantly in young women. This disease much more frequently presents in patients with familial adenomatous polyposis (FAP). FAP is an autosomal dominant inherited disease, which arises from germline mutations in the adenomatous polyposis coli (APC) gene. To clarify the distinctive clinical features of CMV-PTC, a comparison study was performed between familial types and sporadic types. Methods: Between 2007 and 2018, 15 CMV-PTC patients underwent thyroidectomy in Samsung Medical Center. The clinical features of these patients were retrospectively reviewed. Results: All patients were women with a median age of 26 years (range 17-46 years). The median maximum diameter was 1.0 cm (range 0.4-3.5 cm). All tumors underwent immunostaining and showed nuclear and/or cytoplasmic staining for β-catenin. On ultrasonography, most nodules had benign-looking features (well-defined, hypoechoic, and oval to round shapes without calcification), but a few nodules had capsular invasion and taller than wide shape. On preoperative fine-needle aspiration cytology, five patients (33%) were diagnosed as CMV-PTC, nine (60%) as PTC, but one (7%) as follicular neoplasm or PTC-follicular variant. Six patients (40%) had FAP, and four of them had total colectomy due to FAP. Five of them had a family history of FAP or colon cancer, or thyroid cancer. Germline mutations in the APC gene were found in all six patients with CMV-PTC associated with FAP, and five of them had de novo mutations. All patients with FAP-associated CMV-PTC had multiple tumors. All CMV-PTC patients had excellent response to initial therapy. Conclusions: Because of the association between FAP or colon cancer with multifocal CMV-PTC, we confirm that mutational analysis of the APC gene and colonoscopy should be carried out in these patients when multiple thyroid tumors are found.

Contribution to colonic polyposis of recently proposed predisposing genes and assessment of the prevalence of NTHL1- and MSH3-associated polyposes

Technological advances have allowed the identification of new adenomatous and serrated polyposis genes, and of several candidate genes that require additional supporting evidence of causality. Through an exhaustive literature review and mutational screening of 177 unrelated polyposis patients, we assessed the involvement of MCM9, FOCAD, POLQ, and RNF43 in the predisposition to (nonserrated) colonic polyposis, as well as the prevalence of NTHL1 and MSH3 mutations among genetically unexplained polyposis patients. Our results, together with previously reported data and mutation frequency in controls, indicate that: MCM9 and POLQ mutations are not associated with polyposis; germline RNF43 mutations, with a prevalence of 1.5-2.5% among serrated polyposis patients, do not cause nonserrated polyposis; MSH3 biallelic mutations are highly infrequent among European polyposis patients, and the prevalence of NTHL1 biallelic mutations among unexplained polyposes is ~2%. Although nonsignificant, FOCAD predicted deleterious variants are overrepresented in polyposis patients compared to controls, warranting larger studies to provide definite evidence in favor or against their causal association with polyposis predisposition.

Evaluation and comparison of short chain fatty acids composition in gut diseases

BACKGROUND

An altered (dysbiosis) and unhealthy status of the gut microbiota is usually responsible for a reduction of short chain fatty acids (SCFAs) concentration. SCFAs obtained from the carbohydrate fermentation processes are crucial in maintaining gut homeostasis and their determination in stool samples could provide a faster, reliable and cheaper method to highlight the presence of an intestinal dysbiosis and a biomarker for various gut diseases. We hypothesize that different intestinal diseases, such as celiac disease (CD), adenomatous polyposis (AP) and colorectal cancer (CRC) could display a particular fecal SCFAs' signature.

AIM

To compare the fecal SCFAs' profiles of CD, AP, CRC patients and healthy controls, using the same analytical method.

METHODS

In this cross-sectional study, we defined and compared the SCFAs' concentration in fecal samples of 9 AP, 16 CD, 19 CRC patients and 16 healthy controls (HC). The SCFAs' analysis were performed using a gas-chromatography coupled with mass spectrometry method. Data analysis was carried out using Wilcoxon rank-sum test to assess pairwise differences of SCFAs' profiles, partial least squares-discriminate analysis (PLS-DA) to determine the status membership based on distinct SCFAs' profiles, and Dirichlet regression to determine factors influencing concentration levels of SCFAs.

RESULTS

We have not observed any difference in the SCFAs' amount and composition between CD and healthy control. On the contrary, the total amount of SCFAs was significantly lower in CRC patients compared to HC (P = 0.044) and CD (P = 0.005). Moreover, the SCFAs' percentage composition was different in CRC and AP compared to HC. In detail, HC displayed higher percentage of acetic acid (P value = 1.3 × 10-6) and a lower amount of butyric (P value = 0.02192), isobutyric (P value = 7.4 × 10-5), isovaleric (P value = 0.00012) and valeric (P value = 0.00014) acids compared to CRC patients. AP showed a lower abundance of acetic acid (P value = 0.00062) and higher percentages of propionic (P value = 0.00433) and isovaleric (P value = 0.00433) acids compared to HC. Moreover, AP showed higher levels of propionic acid (P value = 0.03251) and a lower level of isobutyric acid (P value = 0.00427) in comparison to CRC. The PLS-DA model demonstrated a significant separation of CRC and AP groups from HC, although some degree of overlap was observed between CRC and AP.

CONCLUSION

Analysis of fecal SCFAs shows the potential to provide a non-invasive means of diagnosis to detect patients with CRC and AP, while CD patients cannot be discriminated from healthy subjects.