Case report: Initial atypical skeletal symptoms and dental anomalies as first signs of Gardner syndrome: the importance of genetic analysis in the early diagnosis.

Background: Gardner syndrome is a rare genetic cancer predisposition disorder characterized by intestinal polyposis, multiple osteomas, and soft and hard tissue tumors. Dental anomalies are present in approximately 30%-70% of patients with Gardner syndrome and can be discovered during routine dental examinations. However, sometimes the diagnosis is challenging due to the high clinical variability and incomplete clinical picture. Herein, we report a family with various dental and bone anomalies, in which the definitive diagnosis was established with the help of a comprehensive genetic analysis based on state-of-the-art next-generation sequencing technology. Case presentation: A 17-year-old female index patient presented with dental (caries, impacted, retained and anteriorly located teeth) and atypical bone anomalies not resembling Gardner syndrome. She was first referred to our Genetic Counselling Unit at the age of 11 due to an atypical bone abnormality identified by a panoramic X-ray. Tooth 3.6 was surgically removed and the histopathology report revealed a Paget's disease-like bone metabolic disorder with mixed osteoblastic and osteoclastic activity of the mandible. A small lumbar subcutaneous tumor was discovered by physical examination. Ultrasound examination of the tumor raised the possibility of a soft tissue propagation of chondromatosis. Her sister, 2 years younger at the age of 14, had some benign tumors (multiple exostoses, odontomas, epidermoid cysts) and impacted teeth. Their mother had also skeletal symptoms. Her lower teeth did not develop, the 9th-10th ribs were fused, and she complained of intermittent jaw pain. A cranial CT scan showed fibrous dysplasia on the cranial bones. Whole exome sequencing identified a heterozygous pathogenic nonsense mutation (c.4700C>G; p.Ser1567*) in the APC gene in the index patient's DNA. Targeted sequencing revealed the same variant in the DNA of the other affected family members (the sister and the mother). Conclusion: Early diagnosis of this rare, genetically determined syndrome is very important, because of the potentially high malignant transformation of intestinal polyps. Dentists should be familiar with the typical maxillofacial features of this disorder, to be able to refer patients to genetic counseling. Dental anomalies often precede the intestinal polyposis and facilitate the early diagnosis, thereby increasing the patients' chances of survival. Genetic analysis may be necessary in patients with atypical phenotypic signs.

Superficial fibromas with CTNNB1 mutation.

Superficial fibromas are a group of mesenchymal spindle cell lesions with pathomorphological heterogeneity and diverse molecular backgrounds. In part, they may be indicators of an underlying syndrome. Among the best-known entities of superficial fibromas is Gardner fibroma, a plaque-like benign tumor, which is associated with APC germline mutations and occurs in patients with familial adenomatosis polyposis (Gardner syndrome). Affected patients also have an increased risk to develop desmoid fibromatosis (DTF), a locally aggressive neoplasm of the deep soft tissue highly prone to local recurrences. Although a minority of DTFs occur in the syndromic context and harbor APC germline mutations, most frequently their underlying molecular aberration is a sporadic mutation in Exon 3 of the CTNNB1 gene. Up to date, a non-syndromic equivalent to Gardner fibroma carrying a CTNNB1 mutation has not been defined. Here, we present two cases of (sub-)cutaneous tumors with a hypocellular and collagen-rich Gardner fibroma-like appearance and pathogenic, somatic CTNNB1 mutations. We aim to differentiate these tumors from other fibromas according to their histological appearance, immunohistochemical staining profile and underlying somatic CTNNB1 mutations. Furthermore, we distinguish them from locally aggressive desmoid fibromatosis regarding their biological behavior, prognosis and indicated therapeutic strategies. Consequently, we call them CTNNB1-mutated superficial fibromas as a sporadic counterpart lesion to syndromic Gardner fibromas.

A novel APC mutation associated with Gardner syndrome in a Chinese family.

Gardner syndrome (GS) is a specific form of familial adenomatous polyposis (FAP), which manifests as colorectal polyps, multiple osteomas and soft tissue tumors, and in the oral cavity as osteomas of the jaws, odontomas, and abnormal tooth counts. The underlying cause of GS is attributed to mutations in the APC gene. Mutations in this gene disrupt the normal functioning of the protein and lead to the development of GS. To further investigate GS, a family affected by the syndrome was selected from Dongguan, Guangdong Province. The family members underwent a comprehensive survey, which involved collecting clinical data and peripheral venous blood samples. The samples were then used for genetic analysis. Whole exome sequencing (WES) and Sanger sequencing techniques were utilized to screen and identify specific mutation sites in the APC gene. The clinical findings for the GS family included the presence of gastrointestinal polyps and odontomas. After analyzing the genetic sequencing results, a novel mutation site c.4266dupA on the APC gene was found in the patients, which leading to the APC protein truncation. As a result of this study, it is suggested that odontoma may be an early indicator of GS. Additionally, the identification of this novel mutation site in the APC gene expands the known spectrum of genetic mutations associated with the disease. This discovery has significant implications for the early diagnosis of GS, thus enabling timely intervention to reduce the risk of developing colon cancer and other related diseases.

Cutaneous desmoid-type fibromatosis: A rare case with molecular profiling.

Fibromatoses encompass a broad group of histopathologically similar fibroblastic/myofibroblastic proliferations with divergent clinical manifestations and behavior. Deep (desmoid-type) fibromatoses are typically large, rapidly growing, and locally aggressive tumors that occur in the abdominal wall, mesentery, and extra-abdominal soft tissue, principally the musculature of the trunk and extremities. Most sporadic cases of desmoid fibromatosis harbor inactivating mutations in CTNNB1, the gene encoding beta-catenin. Tumors occurring in the context of familial adenomatous polyposis and Gardner syndrome bear inactivating mutations in APC. By contrast, mutations in CTNNB1 or APC have not been identified in cases of superficial fibromatosis. Cutaneous involvement by desmoid fibromatosis is exceedingly rare. Here we present a 78-year-old male with desmoid-type fibromatosis arising in the dermis of the right medial calf with a pathogenic mutation in CTNNB1 and a variant of unknown significance in APC.

Torpedo-like lesions in the ocular fundi of Gardner syndrome: hiding in plain view.

Background: The coexistence of fundus torpedoes and Gardner syndrome was initially reported in 1989 and 1992 by Gass and Roseman. Gardner syndrome is a dominantly inherited disease characterized by a multitude of potentially lethal gastrointestinal polyps. Over the ensuing quarter century, several publications demonstrated uncommon, but easily recognized, fundus lesions called Torpedo Maculopathy in apparently normal individuals. These fundus abnormalities were thought to be single and isolated without systemic associations. During the same period of time, a variety of nonspecific fundus abnormalities were described in Gardner syndrome, which, in retrospect, included highly specific lesions that closely resembled macular torpedoes and sometimes were indistinguishable from them.Patient and methods: We now report a confirmed case of Gardner syndrome with numerous fundus torpedoes, and carefully analyze the voluminous literature of both Gardner syndrome and Torpedo Maculopathy.Results: We demonstrate shared features of the fundus lesions in both diseases, and hypothesize that they may have genetic as well as ophthalmoscopic similarities in common.Conclusions: We therefore recommend that individuals with classic isolated torpedoes undergo evaluations for mutations in the Gardner gene (Adenomatous polyposis coli) and for the presence of gastrointestinal polyps and other systemic features of Gardner syndrome. We also suggest that apparently normal individuals, who are genetically related to patients with known classic torpedoes, undergo inspection of their fundi for the possible presence of characteristic lesions.

Gardner-associated fibroma of the neck: role of a multidisciplinary evaluation for familial adenomatous polyposis diagnosis.

INTRODUCTION: Familial adenomatous polyposis (FAP) is a hereditary autosomal dominant disorder characterized by the development of multiple adenomas in the colon and rectum with a lifetime risk of 80%-100% to develop colorectal cancer if undetected or untreated. Gardner-associated fibroma (GAF) is a rare, benign soft tissue lesion with uncertain pathogenesis. GAF is generally associated with FAP in its clinical variant, called Gardner syndrome (GS). CASE DESCRIPTION: A 16-year-old boy with no comorbidities and no significant medical history was referred to the Unit of Hereditary Digestive Tract Tumours, Department of Surgery, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy, for genetic counselling after surgical removal of a right anterior cervical paramedian fibroma. The histopathology on the specimen led to the diagnosis of GAF. He had no family history for colorectal cancer or gastrointestinal polyposis and denied any gastrointestinal symptoms. Physical examination showed a small frontal osteoma and colonoscopy showed the presence of multiple small sessile polyps (>100 polyps, diameter <5 mm) diffusely present on the large bowel. Genetic testing revealed a pathogenic germline variant in the APC gene. The predictive genetic test on the patient's parents and sister was negative for the identified APC mutation; therefore, the patient carried an apparent de novo germline mutation. CONCLUSIONS: GAF may represent a sentinel sign of FAP, preceding gastrointestinal symptoms and endoscopic findings. A careful multidisciplinary approach is determinant for correct and early diagnosis of FAP.

Accumulated genetic mutations leading to accelerated initiation and progression of colorectal cancer in a patient with Gardner syndrome: A case report.

RATIONALE: Gardner syndrome is a rare autosomal dominant disorder with a high degree of penetrance, which is characterized by intestinal polyposis, osteomas, and dental abnormalities. Majority of patients with Gardner syndrome will develop colorectal cancer by the age of 40 to 50 years. Mutations in the adenomatous polyposis coli gene are supposed to be responsible for the initiation of Gardner syndrome. PATIENT CONCERNS: A 22-year-old Chinese female was admitted to our hospital due to abdominal pain and bloody stool. DIAGNOSIS: The patient presented with multiple intestinal polyposis, desmoid tumors, and dental abnormalities was diagnosed as Gardner syndrome and further examination revealed a colon tumor. INTERVENTIONS AND OUTCOMES: Patients were implanted with stents to alleviate bowel obstruction, and were treated with oxaliplatin combined with 5-Fu for 4 cycles, but the efficacy was not good. We performed next generation sequencing of 390 genes for the tumor specimens. We detected adenomatous polyposis coli E1538Ifs∗5, KRAS G12D, NF1 R652C, loss of SMAD4, TP53 R175H, IRF2 p.R82S, TCF7L2 p.A418Tfs∗14, and SMAD4 p.L43F in this patient. LESSONS: We reported serial mutations in key genes responsible for initiation and progression of colorectal cancer from a patient with Gardner syndrome.

A novel large deletion in the APC gene associated with Gardner syndrome in a Chinese family.

INTRODUCTION: Gardner syndrome is a hereditary disease characterized by familial adenomatous polyposis (FAP), accompanied by soft tissue tumors. MATERIAL AND METHODS: a Chinese FAP family was enrolled and followed-up for three years. RESULTS: a novel large germline fragment deletion (EX10_16DEL) of the adenomatous polyposis coli (APC) gene was identified by multiplex ligation-dependent probe amplification (MLPA). An unexpected abdominal tumor grew two years after a subtotal colectomy of the proband. The immunohistochemistry study of the abdominal tumor showed SMA(focal+), calponin(+), ß-catenin(nucleus+) and CD34(focal+), CD117(-), which was consistent with a desmoid tumor. CONCLUSION: when a FAP related desmoid tumor appears, the possibility of Gardner syndrome should be considered. This is the first largest deletion of the APC gene in the Chinese population associated with Gardner syndrome.

Adipocyte-rich CTNNB1-mutated Intramuscular Gardner Fibroma Progressing to Desmoid Fibromatosis.

Gardner fibroma (GF) is a benign soft-tissue tumor that is associated with Gardner syndrome and can progress to, or co-occur with, desmoid fibromatosis (DF). Herein, we report a unique case of an 11-year-old boy who presented with a rapidly growing soft-tissue mass after biopsy of a stable fat-rich lesion present in the calf muscles since infancy, with Magnetic resonance imaging findings suggesting an intramuscular adipocytic tumor. The resection showed GF and DF. DF arising from a preexisting GF (the so-called "GF-DF sequence") is a well-documented phenomenon. Although immunohistochemistry was negative for nuclear ß-catenin expression, a CTTNB1 S45F mutation, which has been associated with aggressive behavior in DF, was identified in both components using a next-generation sequencing-based molecular assay. This is the first time a mutation in CTNNB1 has been identified in GF and the GF-DF sequence, thus expanding our knowledge of the molecular pathogenesis of the GF-DF sequence and highlighting the role of molecular testing in pediatric soft-tissue tumors. The histologic findings of an adipocyte-rich intramuscular GF also are unique, expanding the morphological spectrum of GF and adding GF to the differential diagnosis of intramuscular lesions with an adipocytic component.

Novel pathogenic alterations in pediatric and adult desmoid-type fibromatosis - A systematic analysis of 204 cases.

Desmoid-type fibromatosis (DTF, aggressive fibromatosis) is a non-metastasizing mesenchymal neoplasm of deep soft tissue with a tendency towards local recurrence. Genetic alterations affecting canonical Wnt/ß-catenin signaling are reported in the majority of DTF. While most sporadic DTF harbor somatic mutations in CTNNB1, germline mutations in adenomatous polyposis coli (APC) are known to occur in hereditary DTF types (FAP, Gardner-Syndrome). Additional single nucleotide variants (SNVs) in AKT1 (E17K) and BRAF (V600E) were reported in pediatric DTF with potential clinical implications. We performed targeted next-generation sequencing (NGS) in a large cohort of 204 formalin-fixed DTF samples, comprising 22 pediatric cases (patients age ≤18 years). The mutational status was correlated with clinicopathological characteristics. Overall, deleterious CTNNB1 mutations were detected in 89% of DTF, most frequently affecting the serine/threonine phosphorylation sites T41 and S45 of ß-catenin. While the T41A CTNNB1 mutation was significantly more often identified in the mesenterial localization, DTF originating from extra-intestinal sites more frequently harbored the S45P CTNNB1 alteration. Beyond common mutations in CTNNB1, additional SNVs were demonstrated in 7% of the DTF cohort and in 18% of the pediatric DTF subgroup. The mutational spectrum included deleterious mutations in AKT1 (G311S/D and T312I), ALK (R806H and G924S), AR (A159T), EGFR (P848L), ERBB2 (H174Y), IDH2 (H354Y), KIT (V559D), RET (T1038A), SDHA (R325M), and SDHD (R115W), as characterized by in silico prediction tools. In conclusion, our study indicates that DTF may harbor a broader mutational spectrum beyond CTNNB1 mutations, comprising targetable alterations including the herewith first reported imatinib-sensitive KIT V559D mutation in DTF.

[Familial adenomatous polyposis, desmoid tumors and Gardner syndrome]. / Polypose adénomateuse familiale, tumeurs desmoïdes et syndrome de Gardner.

About 15 % of patients with familial adenomatous polyposis "PAF" develop one or more desmoid tumors in their lifetime. These are benign mesenchymal tumors with local aggressivity but with no potential for metastases. Most of the desmoids tumors result from a sporadic genetic anomaly in the ß catenin gene. When related to familial adenomatous polyposis or "PAF", this mutation is not present, and the patients must be sent in genetic counselling. The PAF is a dominant autosomic illness related to a germinal mutation in the APC gene. Sometimes, these tumors can be the first manifestation of the illness. The diagnosis in a context of PAF can be easily done by imaging, but a pathological confirmation is needed. These tumors raise a therapeutic problem because of their heterogeneity and the absence of predictive biomarkers along illness evolution. The identification of prognostic biological and clinical factors would make easier the selection of patients requiring first-line treatment, as spontaneous remissions have also been observed in patients with FAP whom which an active surveillance could also be a valid therapeutic option. The particularity of desmoids tumors associated to PAF lies in their predominantly intra-abdominal location and the risk of complication. In the last ten years, surgery has largely given way to conservative treatments such as chemotherapy and more recently to tyrosine kinase inhibitors that have shown their efficacy with a significant improvement in progression-free survival of patients.

Identification of aggressive Gardner syndrome phenotype associated with a de novo APC variant, c.4666dup.

Gardner syndrome describes a variant phenotype of familial adenomatous polyposis (FAP), primarily characterized by extracolonic lesions including osteomas, dental abnormalities, epidermal cysts, and soft tissue tumors. We describe a 2-yr-old boy presenting with a 2-cm soft tissue mass of the forehead. Pathologic evaluation revealed a nuchal-type/Gardner-associated fibroma. Sequencing of the APC gene revealed a pathologic variant c.4666dupA. Parental sequencing of both blood and buccal tissue supported the de novo occurrence of this pathologic variant. Further imaging revealed a number of additional lesions including a large lumbar paraspinal desmoid, a 1-cm palpable lesion posterior to the left knee, firm lesions on bilateral heels, and multiple subdermal lesions. Colonoscopy was negative. This case illustrates a genetic variant of Gardner syndrome resulting in an aggressive early childhood phenotype and highlights the need for an individualized approach to treatment.

Identification of a mutL­homolog 1 mutation via whole­exome sequencing in a Chinese family with Gardner syndrome.

Gardner syndrome (GS), a variant of familial adenomatous polyposis, is a rare genetic disorder with autosomal dominant inheritance, characterized by the presence of multiple intestinal polyps, multiple osteomas, dental abnormalities and soft tissue tumors. To date, only a few gene mutations have been demonstrated to be responsible for GS. To explore potential unknown mutations responsible for GS, the present study used whole­exome sequencing of two affected individuals from a family with GS to identify a candidate mutation in mutL­homolog (MLH)1. The two patients with GS were diagnosed based on a combination of clinical features, family history, physical examinations and cone­beam computed tomographic imaging. Through whole­genome sequencing, the present study subsequently identified a missense mutation in MLH1 (NM_000249.3:p.Tyr379Ser/c.1136A>C), which was further confirmed by Sanger sequencing. Furthermore, the amino acid residue p.Tyr379 was identified to be highly conserved among different species through sequence alignment with ClustalW2. In conclusion, the results identified for the first time a MLH1 missense mutation (NM_000249.3:​p.Tyr379Ser/c.1136A>C) in a Chinese family with GS, thus broadening the range of mutated genes associated with GS. This highlights the value of whole­exome sequencing in identifying disease mutations in a family.

Role of GALNT12 in the genetic predisposition to attenuated adenomatous polyposis syndrome.

The involvement of GALNT12 in colorectal carcinogenesis has been demonstrated but it is not clear to what extent it is implicated in familial CRC susceptibility. Partially inactivating variant, NM_024642.4:c.907G>A, p.(D303N), has been previously detected in familial CRC and proposed as the causative risk allele. Since phenotypes of the described carrier families showed not only CRC but also a polyp history, we hypothesized that GALNT12 could be involved in adenoma predisposition and consequently, in hereditary polyposis CRC syndromes. For that purpose, we have screened the GALNT12 gene in germline DNA from 183 unrelated attenuated polyposis patients. c.907G>A, p.(D303N) was detected in 4 cases (MAF = 1.1%) and no other candidate variants were found. After segregation studies, LOH analyses, glycosylation pattern tests and case-control studies, our results did not support the role of c.907G>A, p.(D303N) as a high-penetrance risk allele for polyposis CRC.

Attenuated adenomatous polyposis of the large bowel: Present and future.

Attenuated adenomatous polyposis (AAP) is a poorly understood syndrome, that can be defined as the presence of 10-99 synchronous adenomas in the large bowel, and it is considered a phenotypic variant of familial adenomatous polyposis (FAP). This definition has the advantage of simplicity, but it may include sporadic multiple adenomas of the large bowel at an extreme, or FAP cases on the other side. AAP shows a milder phenotype than FAP, with an older age of onset of adenomas and cancer, and less frequent extracolonic manifestations. AAP may be diagnosed as a single case in a family or, less frequently, it may be present in other family members, and it shows distinct pattern of inheritance. In less than 50% of cases, it may be caused by adenomatous polyposis coli (APC) or MUTYH mutations, referred to as APC-associated polyposis, inherited as an autosomal dominant trait, or MUTYH-associated polyposis, which shows an autosomal recessive mechanism of inheritance, respectively. Surveillance should rely on colonoscopy at regular intervals, with removal of adenomas and careful histological examination. When removal of polyps is not possible or advanced lesions are observed, the surgical approach is mandatory, being subtotal colectomy with ileo-rectal anastomosis the treatment of choice. Studies on this syndrome are lacking, and controversies are still present on many issues, thus, other clinical and genetic studies are requested.

A role for the vitamin D pathway in non-intestinal lesions in genetic and carcinogen models of colorectal cancer and in familial adenomatous polyposis.

Vitamin D is implicated in the etiology of cancers of the gastrointestinal tract, usually characterized by alteration in the APC/ß-catenin/TCF tumor suppressor pathway. The vitamin D receptor (VDR) is also implicated in cardiovascular and skin diseases as well as in immunity. Activated VDR can indirectly alter ß-catenin nuclear localization and directly suppress ß-catenin/TCF mediated transcriptional activity. We treated VDR null mice with the carcinogen azoxymethane (AOM) and generated mice bearing a mutated APC (hypomorph) on a VDR null background (Apc1638N/+Vdr-/-). VDR null mice do not develop GI or extra-colonic tumors but loss of VDR decreased intestinal tumor latency and increased progression to adenocarcinoma in both models. AOM treatment of VDR null mice also caused squamous cell carcinoma of the anus. Although levels and distribution of total or activated ß-catenin in the epithelial component of tumors were unaffected by loss of VDR, ß-catenin dependent cyclin D1 expression was affected suggesting a direct VDR effect on ß-catenin co-activator activity. Extra-colonic mucosa manifestations in Apc1638N/+Vdr-/- animals included increased nuclear ß-catenin in submucosal stromal cells, spleno- and cardiomegaly and large epidermoid cysts characteristic of the FAP variant, Gardner's syndrome. Consistent with this, SNPs in the VDR, vitamin D binding protein and CYP24 as well as mutations in APC distal to codon 850 were strongly associated with Gardners syndrome in a cohort of 457 FAP patients, This work suggests that alterations in the vitamin D/VDR axis are important in Gardner's syndrome, as well as in the etiology of anal cancer.

Gardner's syndrome presenting with a fibromatous tumour of the parotid.

INTRODUCTION: Gardner's syndrome is the association of familial adenomatous polyposis (FAP) with an anaphase promoting complex (APC) gene mutation and several extradigestive manifestations: osteomas, epidermal cysts and desmoid tumours. Only 2 cases of FAP associated with parotid tumour have been reported in the literature: one carcinoma and one pleomorphic adenoma. CASE REPORT: We report the case of a 23-year-old man with Gardner's syndrome presenting with a fibromatous tumour of the left parotid gland. The other clinical manifestations were an osteoma of the skull base and a mesentery desmoid tumour. Left total parotidectomy was performed, followed by gastroscopy and colonoscopy, demonstrating numerous colonic adenomas. Genetic analysis revealed an APC gene mutation, confirming the diagnosis. Total prophylactic colectomy was performed. CONCLUSIONS: This is the first reported case of Gardner's syndrome associated with a fibromatous tumour of the parotid. Early management of FAP is essential to prevent colorectal cancer that occurs in 100% of untreated cases. The rarity of this syndrome and the parotid site can lead to delayed diagnosis.

Oral mucosal stigmata in hereditary-cancer syndromes: From germline mutations to distinctive clinical phenotypes and tailored therapies.

Numerous familial tumor syndromes are associated with distinctive oral mucosal findings, which may make possible an early diagnosis as an efficacious marker for the risk of developing visceral malignancies. In detail, Familial Adenomatous Polyposis (FAP), Gardner syndrome, Peutz-Jeghers syndrome, Cowden Syndrome, Gorlin Syndrome, Lynch/Muir-Torre Syndrome and Multiple Endocrine Neoplasia show specific lesions of the oral mucosa and other distinct clinical and molecular features. The common genetic background of the above mentioned syndromes involve germline mutations in tumor suppressor genes, such as APC, PTEN, PTCH1, STK11, RET, clearly implied in both ectodermal and mesodermal differentiation, being the oral mucosal and dental stigmata frequently associated in the specific clinical phenotypes. The oral and maxillofacial manifestations of these syndromes may become visible several years before the intestinal lesions, constituting a clinical marker that is predictive for the development of intestinal polyps and/or other visceral malignancies. A multidisciplinary approach is therefore necessary for both clinical diagnosis and management of the gene-carriers probands and their family members who have to be referred for genetic testing or have to be investigated for the presence of visceral cancers.