Genotypic and Phenotypic Characteristics of Hereditary Colorectal Cancer

The genomic causes and clinical manifestations of hereditary colorectal cancer (HCRC) might be stratified into 2 groups, namely, familial (FCRC) and a limited sense of HCRC, respectively. Otherwise, FCRC is canonically classified into 2 major categories; Lynch syndrome (LS) or associated spectra and inherited polyposis syndrome. By contrast, despite an increasing body of genotypic and phenotypic traits, some FCRC cannot be clearly differentiated as definitively single type, and the situation has become more complex as additional causative genes have been discovered. This review provides an overview of HCRC, including 6 LS or associated spectra and 8 inherited polyposis syndromes, according to molecular pathogenesis. Variants and newly-identified FCRC are particularly emphasized, including MUTYH (or MYH)-associated polyposis, Muir-Torre syndrome, constitutional mismatch repair deficiency, EPCAM-associated LS, polymerase proofreading-associated polyposis, RNF43- or NTHL1-associated serrated polyposis syndrome, PTEN hamartoma tumor syndrome, and hereditary mixed polyposis syndrome. We also comment on the clinical utility of multigene panel tests, focusing on comprehensive cancer panels that include HCRC. Finally, HCRC surveillance strategies are recommended, based on revised or notable concepts underpinned by competent validation and clinical implications, and favoring major guidelines. As hereditary syndromes are mainly attributable to genomic constitutions of distinctive ancestral groups, an integrative national HCRC registry and guideline is an urgent priority.

Giant Gastric Folds in Juvenile Polyposis

To advance the diagnostic accuracy of juvenile polyposis syndrome, an important yet often difficult diagnosis, we describe in detail a new and medically significant presentation. This hereditary and high-risk GI cancer syndrome is often associated with hereditary hemorrhagic telangiectasia, as in this 47-year-old female patient with a <i>SMAD4</i> germline pathogenic mutation. Total gastrectomy revealed giant gastric folds with inflamed foveolar hyperplasia consuming most of the gastric cardia and body but sparing the antrum. Together, this gross and histologic pathology mimics Ménétrier’s disease, an exceedingly rare and acquired protein-losing hypertrophic gastropathy. Classical gastric juvenile polyposis almost always and principally involves the antrum with multiple distinctive inflammatory <i>polyps</i> rather than the newly illustrated <i>giant gastric folds</i> of this case. No reports of giant gastric folds in juvenile polyposis have appeared in the literature. The distinction between juvenile polyposis and Ménétrier’s disease is essential due to their disparate clinical outcomes and management. The differential considerations for giant gastric folds and inflamed gastric foveolar hyperplasia are fully reviewed. On the basis of this report, the differential for giant gastric folds must now expand to include juvenile polyposis syndrome. Genetic testing for pathogenic germline mutations of the 2 known causative genes of this syndrome, namely <i>SMAD4</i> and <i>BMPR1A</i>, are readily available and should become part of the evaluation of giant gastric folds, particularly in view of the neoplastic and hereditary aspects of juvenile polyposis syndrome.

Hereditary Colorectal Cancer and Polyposis Syndromes

The majority of cases of inherited colorectal cancer (CRC) are accounted for by two syndromes: Lynch syndrome and familial adenomatous polyposis (FAP). In the management of FAP, the role of prophylactic surgery is clearly defined, although the optimal procedure for an individual patient depends on a number of factors. In the management of Lynch syndrome, the indications for prophylactic procedures are emerging. The authors address the clinical evaluation, investigation findings, medical and surgical therapy, and extracolonic diseases of FAP, attenuated form of FAP (AFAP), MYH-associated polyposis, Lynch syndrome, familial colorectal cancer type X (FCCTX), hyperplastic polyposis syndrome, Peutz-Jeghers syndrome, and juvenile polyposis syndrome. AFAP has been described that is associated with fewer adenomas and later development of CRC compared with classic FAP. The AFAP phenotype occurs in less than 10% of FAP patients. The clinical criteria for AFAP are no family members with more than 100 adenomas before the age of 30 years and (1) at least two patients with 10 to 99 adenomas at age over 30 years or (2) one patient with 10 to 99 adenomas at age over 30 years and a first-degree relative with CRC with few adenomas. Given that polyposis has a later onset and the risk of CRC is less well established in AFAP, some authors question whether prophylactic colectomy is necessary in all AFAP patients. This review contains 26 tables and 173 references Keywords: Colorectal cancer, Lynch syndrome, hyperplastic polyp, Peutz-Jeghers syndrome, juvenile polyposis syndrome, familial adenomatous polyposis

Solitary Juvenile Polyp at a Rural Ugandan Hospital Presenting with Recurrent Rectal Bleeding

Juvenile polyps (JP) are rare but important causes of acute gastrointestinal symptoms in children. They are a recognized cause of painless rectal bleeding in preschool age children and also the most common intraluminal disorder of the colon in children They are often solitary, pedunculated and small in size but may occasionally grow to large sizes or occur in great numbers, as in juvenile polyposis syndrome. Histologically juvenile polyps are similar to inflammatory polyps with irregular dilated glands, lamina propria expansion and granulation tissue expansion. Sporadic juvenile polyps of the colon occur in up to 2 percent of children under the age of 10 years, are usually solitary, and are not associated with an increased cancer risk. The etiology, diagnosis, clinical presentation, and management of these intestinal polyps depend on the type of polyp or polyposis syndrome. A change in bowel habits, abdominal pain, rectal bleeding, rectal prolapse, and even intussusception may be the initial presentation in children. In addition to a careful history, including a detailed family history, a physical examination, contrast studies, and endoscopic examination are vital diagnostic tools. Juvenile polyps may also present with prolapse of the polyp from the anus, abdominal pain due to intussusception or may even be asymptomatic. All such polyps should be removed by colonoscopy or transanal resection

A Rare Case of Serrated Polyposis Syndrome with the MSH6 and SMARCA4 variants

Serrated polyposis syndrome (SPS) is the most common form of polyposis syndrome and has been shown to increase the risk of colorectal cancer (CRC). The genetic pathway of CRC in SPS is different from the classic adenomatous polyposis coli (APC) pathway, which accounts for 70–80% of cases of CRC. Most commonly, SPS mutations include BRAF and KRAS, with activation of the RAS-RAF-MAP kinase pathway involved in the pathogenesis of serrated lesions. We present a rare case of SPS in a 32-year-old woman with MSH6 and SMARCA4 variants, which have not previously been reported in the literature.