Here we reported a particular case of MUTYH-associated polyposis (MAP) that had only one rare heterozygous variant, but some particular clinical manifestations contributed to occur in this male patient by only one defective MUTYH allele were worth of further investigation. We reported a case of MAP. It is about a 33-year-old man with chief complaints of hematochezia who had multiple polyps that were found in his colon via colonoscopy. He followed his doctor\'s advice and performed a genetic analysis examination. Germline test was positive for a major heterozygous variant: chr1:45800165 on the MUTYH gene. MUTYH gene sequence analysis confirmed the following heterozygous variant: c.55CT (p.R19X) in exon 2 (ClinVar NM_001128425). Unfortunately, his mother and daughter have the ILK variant according to genetic analysis. However, this variant at the site was not detected in his father. Various types of polyps were found on repeated colonoscopy, which tended to become latent cancerous in the future. This case indicated that awareness of the risk of carcinogenesis of polyps in carriers of monoallelic variants might accordingly increase, and our understanding of the type of genetically related disease will be enhanced by us.

Desmoid tumors are benign proliferations of spindle cells originating in fibro-aponeurotic tissue. Many patients with familial adenomatous polyposis (FAP) die from desmoid tumors, which can arise spontaneously but often appear to be surgically induced by prophylactic colectomy. Desmoid tumors are the second most common cause of death in patients with FAP, second to colorectal cancer. Many patients can live a long life with desmoid tumors without symptoms, but when symptoms (ranging from bowel or ureteric obstruction to bowel perforation with abscess and fistula) appear or there is a risk of functional impairment, a wide spectrum of therapies (local and systemic) are valuable in improving the symptoms and controlling the disease. A half-Japanese, half-Caucasian male, who had been diagnosed with intra-abdominal desmoid tumors associated with FAP at age 13, was treated using abdominal wall incision for decompression and chemotherapy from the age of 38. The therapeutic outcome was progressive disease, based on the modified response evaluation criteria in solid tumors (mRECIST), and when he visited our hospital at age 41 the desmoid tumor had invaded the small bowel with a fistula to the abdominal wall. We performed a palliative operation to improve his symptoms, which were fever, abdominal pain, vomiting, and difficulty eating. As the tumor was extremely large and had invaded the small intestine, massive resection including the small intestine was required. To prepare for anticipated massive bleeding, a balloon catheter was placed in the superior mesenteric artery just prior to surgery. Although the operation was extremely difficult, following surgery the patient regained his ability to eat and when discharged was ambulatory and without short-bowel syndrome. We report our experience treating one of the largest reported intraperitoneal desmoid tumors. Resection resulted in a good postoperative course, with improved quality of life and prognosis.

Pathogenic AXIN2 variants cause absence of permanent teeth (hypodontia), sparse hair and eye brows (ectodermal dysplasia), and gastrointestinal polyps and cancer. Inheritance is autosomal dominant with variable penetrance. Only twenty- five patients have been reported from five families. A Mayo Clinic pilot program tested 3009 newly diagnosed cancer patients for pathogenic germline variants in 83 hereditary cancer genes, including AXIN2. We found only one patient with a pathogenic AXIN2 variant.
The proband was a 49 year-old female who came to Otolaryngology clinic complaining of right-sided nasal obstruction. Biopsy of identified nasal polyp revealed olfactory neuroblastoma (esthesioneuroblastoma). Surgical resection with gross, total tumor resection was followed by radiation therapy. The patient enrolled in a clinical pilot of genetic testing and a pathogenic variant in AXIN2, c.1822del (p.Leu608Phefs*81) (NM_004655.3) was found. She was seen in Medical Genetics clinic and found to have a personal history of hypodontia. Her eyebrows, hair, and nails were all normal. She underwent upper endoscopy and colonoscopy. A four mm gastric adenoma was found and removed.
This is the first case reported on a patient with a pathogenic, germline AXIN2 variant and an olfactory neuroblastoma or a gastric adenoma. We propose that these could be features of the AXIN2 phenotype. The known association between gastric adenomas and familial adenomatous polyposis, the other Wnt/beta-catenin disorder, supports the hypothesis that pathogenic AXIN2 variants increase risk as well. As the odds of a chance co-occurrence of a pathogenic AXIN2 variant and an olfactory neuroblastoma are so rare, it is worth exploring potential causation. We are building a clinical registry to expand understanding of the AXIN2 phenotype and request any clinicians caring for patients with pathogenic AXIN2 variants to contact us.

Polymerase proofreading-associated polyposis, caused by germline variants in the exonuclease domains of POLD1 and POLE, is a dominantly inherited rare condition characterized by oligo-adenomatous polyposis and increased risk of colorectal cancer, endometrial cancer and brain tumours. We report the first Japanese case of polymerase proofreading-associated polyposis carrying a POLD1 variant. The proband was a Japanese woman who had undergone resections of early colorectal carcinomas repeatedly and a hysterectomy with bilateral oophorectomy for endometrial cancer, all of which were diagnosed within 2 years after the first colectomy at 49 year old. Colonoscopic examinations demonstrated at least 14 non-cancerous polypoid lesions, some of which were histologically confirmed to be adenoma. Multigene panel sequencing identified a missense variant in POLD1 (c.1433G>A). Although her relatives did not undergo genetic testing, her father and paternal grandfather died of brain tumours at 53 and ~30 years of age, respectively.

BACKGROUND: We are reporting a rare case of MUTYH-associated polyposis, a colorectal cancer hereditary syndrome, diagnosticated after an intussusception. Colorectal cancer is an important cause of cancer related mortality that can be manifested by an intussusception, a rare occurrence in adults and almost always related to tumors. Approximately 5% of colorectal cancers can be attributed to syndromes known to cause hereditary colorectal cancer, such as MUTYH-associated polyposis, autosomal genetic syndrome associated with this disease.
METHODS: We present the case of a 44 years old male, that sought medical consultation with a complaint of abdominal discomfort, that after five days changed its characteristics. The patient was sent to the emergency department were a CT-scan revealed intestinal sub-occlusion by ileocolic invagination. Right colectomy was carried out. The anatomic-pathological examination revealed a moderately differentiated mucinous adenocarcinoma and multiples sessile polyps, which led to the suspicion of a genetic syndrome. In the genetics analysis two mutations were observed in the MUTYH gene, and MUTYH-associated polyposis was diagnosticated.
CONCLUSIONS: This case demonstrates the importance of meticulous analysis of the patient examinations results to identify possible discrete alterations that can lead to improved understanding of disease.