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.

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.

Recurrent CTNNB1 mutations in craniofacial osteomas.

Osteoma is a benign bone forming tumor predominantly arising on the surface of craniofacial bones. While the vast majority of osteomas develops sporadically, a small subset of cases is associated with Gardner syndrome, a phenotypic variant of familial adenomatous polyposis caused by mutations in the APC gene resulting in aberrant activation of WNT/ß-catenin signaling. In a sequencing analysis on a cohort of sporadic, non-syndromal osteomas, we identified hotspot mutations in the CTNNB1 gene (encoding ß-catenin) in 22 of 36 cases (61.1%), harbouring allelic frequencies ranging from 0.04 to 0.53, with the known S45P variant representing the most frequent alteration. Based on NanoString multiplex expression profiling performed in a subset of cases, CTNNB1-mutated osteomas segregated in a defined "WNT-cluster", substantiating functionality of CTNNB1 mutations which are associated with ß-catenin stabilization. Our findings for the first time convincingly show that osteomas represent genetically-driven neoplasms and provide evidence that aberrant WNT/ß-catenin signaling plays a fundamental role in their pathogenesis, in line with the well-known function of WNT/ß-catenin in osteogenesis. Our study contributes to a better understanding of the molecular pathogenesis underlying osteoma development and establishes a helpful diagnostic molecular marker for morphologically challenging cases.

What's new in bone forming tumours of the skeleton?

Bone tumours are difficult to diagnose and treat, as they are rare and over 60 different subtypes are recognised. The emergence of next-generation sequencing has partly elucidated the molecular mechanisms behind these tumours, including the group of bone forming tumours (osteoma, osteoid osteoma, osteoblastoma and osteosarcoma). Increased knowledge on the molecular mechanism could help to identify novel diagnostic markers and/or treatment options. Osteoid osteoma and osteoblastoma are bone forming tumours without malignant potential that have overlapping morphology. They were recently shown to carry FOS and-to a lesser extent-FOSB rearrangements suggesting that these tumours are closely related. The presence of these rearrangements could help discriminate these entities from other lesions with woven bone deposition. Osteosarcoma is a malignant bone forming tumour for which different histological subtypes are recognised. High-grade osteosarcoma is the prototype of a complex karyotype tumour, and extensive research exploring its molecular background has identified phenomena like chromothripsis and kataegis and some recurrent alterations. Due to lack of specificity, this has not led to a valuable novel diagnostic marker so far. Nevertheless, these studies have also pointed towards potential targetable drivers of which the therapeutic merit remains to be further explored.

Dental anomalies in pediatric patients with familial adenomatous polyposis.

Familial adenomatous polyposis patients often present with non-malignant extra-intestinal manifestations which include dental anomalies that may be evident prior to the appearance of the colonic adenomas. The aims of this study were to describe the prevalence and type of dental anomalies and the relationships between gene mutations and dental anomalies in these patients. Twenty-two pediatric familial adenomatous polyposis patients and 46 controls, who were age and gender matched participated. Familial adenomatous polyposis patient's had a dental examination with panoramic radiograph and medical record review for age at diagnosis, the presence of the adenomatous polyposis coli gene mutation, and determination of other extra-intestinal manifestations on the body. The control group was identified from a retrospective chart review and selected if there was a current panoramic radiograph. The only significant difference between familial adenomatous polyposis patients and controls were the presence of jaw osteomas and sclerosis (p = .0001). Patients with a mutation in, or upstream of codon 1309 had a higher frequency of osteomas (77.8%) and jaw-bone sclerosis (44.4%), and 77% of these had at least one dental anomaly. This preliminary study showed an association between a genetic variant at, or upstream of codon 1309, and radiographic dental anomalies.

[Ectopic craniopharyngioma and Gardner's syndrome: Case report and literature review]. / Craneofaringioma ectópico y síndrome de Gardner: a propósito de un caso y revisión de la literatura.

INTRODUCTION: Craniopharyngioma accounts for around 3% of all primary tumours of the central nervous system. It is usually located in the suprasellar region, although it may also have an ectopic location. CASE REPORT: The case is presented on 29 year-old male who underwent surgery for a jaw osteoma when he was 19 years old and was subsequently diagnosed with Gardner's syndrome. He was admitted in our Hospital with right facial paresis and diplopia of one day onset. The examination showed mild right VII and VI cranial nerves paresis. Magnetic resonance imaging of the brain demonstrated a rounded solid and cystic lesion with well-defined contours of about 2cm in diameter filling the fourth ventricle. The patient underwent a posterior fossa craniotomy using a telovelar approach with complete removal of the tumour implanted at roof level of the fourth ventricle. The final histology of the tumour was reported as adamantinomatous craniopharyngioma. CONCLUSION: Craniopharyngioma may appear in another location other than the suprasellar region. Its atypical location may be related to Gardner syndrome by still unknown pathogenic mechanisms.

Novel mouse model for Gardner syndrome generated by a large-scale N-ethyl-N-nitrosourea mutagenesis program.

Mutant mouse models are indispensable tools for clarifying the functions of genes and elucidating the underlying pathogenic mechanisms of human diseases. We carried out large-scale mutagenesis using the chemical mutagen N-ethyl-N-nitrosourea. One specific aim of our mutagenesis project was to generate novel cancer models. We screened 7012 animals for dominant traits using a necropsy test and thereby established 17 mutant lines predisposed to cancer. Here, we report on a novel cancer model line that developed osteoma, trichogenic tumor, and breast cancer. Using fine mapping and genomic sequencing, we identified a point mutation in the adenomatous polyposis coli (Apc) gene. The Apc1576 mutants bear a nonsense mutation at codon 1576 in the Apc gene. Although most Apc mutant mice established thus far have multifocal intestinal tumors, mice that are heterozygous for the Apc1576 mutation do not develop intestinal tumors; instead, they develop multifocal breast cancers and trichogenic tumors. Notably, the osteomas that develop in the Apc1576 mutant mice recapitulate the lesion observed in Gardner syndrome, a clinical variant of familial adenomatous polyposis. Our Apc1576 mutant mice will be valuable not only for understanding the function of the Apc gene in detail but also as models of human Gardner syndrome.

Gardner's syndrome: a clinical and genetic study of a family.

OBJECTIVE: Gardner syndrome (GS) is an autosomal dominant genetic disorder with almost complete penetrance (80%) and variable expression. GS is a variant of familial adenomatous polyposis and characterized by extracolonic manifestations including osteomas and soft tissue tumors (desmoid tumors, epidermoid cysts). We describe clinical and surgical approaches in a family in which the genetic disorder was diagnosed in 3 generations. STUDY DESIGN: The studied family underwent clinical history and instrumental and genomic studies. Two members of this family, affected with GS, underwent surgery for skeletal osteomas. RESULTS: The patients that we treated with clinical-instrumental monitoring for a period of 5 years had no major disturbances of the stomatognathic system and no clinical signs of pathology of the gastrointestinal tract, eyes, or endocrine systems. CONCLUSIONS: The orofacial complex disorders are exclusively functional and esthetic, concerning primarily the stomatognathic system. We had no cases of malignant transformation of osteomatosis lesions. Clinical sequelae are manly facial eumorphy and occlusion problems of the temporomandibular joint.

Infantile osteoma cutis as a presentation of a GNAS mutation.

We report a case of osteoma cutis associated with a GNAS mutation in a 7-month-old boy. The patient displayed no other laboratory or physical abnormalities to suggest other GNAS-associated disorders of cutaneous ossification, including Albright's hereditary osteodystrophy or pseudohypoparathyroidism 1A, although a history of intrauterine growth restriction was troubling for progressive osseous heteroplasia. A review of the clinical and laboratory manifestations of these disorders is discussed, as well as differentiating features.

Acquired plate-like osteoma cutis.

Plate-like osteoma cutis is a rare disorder that has been historically classified as a congenital syndrome. It has a possible relationship to a mutation in the gene (GNAS1) that encodes the α-subunit of the stimulatory G protein, which regulates adenyl cyclase activity. We report a case of extensive plaque-like masses on the scalp and face with no abnormalities in calcium or phosphate metabolism and no preceding inflammatory cutaneous conditions. With less than ten reported cases, to our knowledge, this is one the few cases of acquired plate-like osteoma cutis described in the literature.

Multiple miliary osteoma cutis is a distinct disease entity: four case reports and review of the literature.

BACKGROUND: Multiple miliary osteoma cutis (MMOC) is a rare nodular skin disease characterized by tiny bone nodules which usually form on the facial skin, typically in middle age. The aetiology of this phenomenon is poorly understood. OBJECTIVES: To search for possible bone formation progenitors and to look for a possible association with mutations in the GNAS gene (encoding the G-protein α-stimulatory subunit) and related hormonal parameters in patients with MMOC. We also reviewed the literature and discuss the aetiology and pathogenesis of adult-onset primary osteomas. METHODS: We report four cases of MMOC. Histological samples were analysed for bone morphogenetic protein (BMP)-2, BMP-4 and oestrogen receptor-α known to be involved in bone formation. Endocrinological laboratory investigations and hand X-rays were performed to exclude a systemic disease. The GNAS gene was sequenced from DNA extracted from peripheral blood in all four patients and from a skin sample in one patient to exclude somatic mutations. RESULTS: Histological analyses revealed intramembranous cutaneous bone formation resembling the findings seen in GNAS gene-based osteoma cutis disorders. However, we did not find any germline or somatic GNAS gene mutations in our patients and all laboratory investigations gave normal results. BMP-2 and -4 were expressed normally in MMOC samples, but oestrogen receptor-α was not expressed. Altogether 47 MMOC cases, 41 female and six male, have been published between 1928 and 2009. Of these cases, 55% had a history of pre-existing acne and only 15% had extrafacial osteomas. CONCLUSIONS: MMOC is a rare but distinct disease entity of unknown aetiology. Histologically, the tiny nodular osteomas show intramembranous superficial ossification but the aetiology appears to be different from GNAS-related disorders. The osteomas seem to increase slowly in number after appearing in middle age.

[Gardner fibroma: case report and discussion of a new soft tissue tumor entity]. / Gardner-Fibrom: Eine neue mesenchymale Tumorentität als Indikatorläsion.

Gardner fibroma represents a rare and recently described soft tissue tumor entity in children and young adults. It consists of haphazardly arranged coarse and hyalinized collagen fibers combined with loosely arranged bland spindle and fibroblastic cells. The case of a 13-year-old male patient with Gardner fibroma and osteoma and multicentric desmoid type fibromatosis in his mother is presented with detection of a (heterozygotic) germline mutation of the APC gene leading to a de novo stop codon (deletion of base pairs 5033-5036). FISH analysis revealed a structural loss of heterozygosity (LOH) in the APC gene on chromosomal locus 5q21 in one out of five analysed desmoids of the mother, no LOH of APC gene in the Gardner fibroma. Gardner fibroma in children and young adults may serve as an indicator lesion for familial adenomatous polyposis (FAP), Gardner syndrome, a familial desmoid type fibromatosis without other manifestations of APC or a new APC gene mutation. For the clinician, this diagnosis should be commented upon accordingly by the surgical pathologist. As the result of a detected APC gene mutation, continuous follow-up for the development of colorectal tumors and desmoid type fibromatosis as well as a familial screening for FAP is recommended.

The role of Cone beam CT in the evaluation and management of a family with Gardner's syndrome.

Gardner's syndrome (GS) is a hereditary autosomal dominant disease of the colon that presents with extra-colonic manifestations such as osteomas, skin lesions and dental abnormalities. Osteomas are commonly found in the skull, jaws and the paranasal sinuses. We present a family of four sisters affected with GS with a wide range of anomalies. The role of Cone beam computed tomography (CBCT) in the early detection and evaluation of osteomas and dental anomalies with precise assessment of their relationship to adjacent anatomic structures is described here in detail. The careful interpretation of CBCT may be of a great value in surgical and orthodontic treatment planning in the presence of jaw lesions. Management of dental problems in GS may be challenging due to the presence of odontomas and increased bone density. A multidisciplinary approach in the management of GS can achieve the best treatment results.

A case report of Gardner syndrome with hereditary widespread osteomatous jaw lesions.

Gardner syndrome (GS) is an abnormality of familial adenomatous polyposis accompanied by characteristic jaw lesions. Gardner syndrome intestinal polyps have a 100% risk of undergoing malignant transformation; consequently, early identification and surgical intervention of the disease are important to prolong the life of the patient. We present a case of GS in a 55-year-old woman. Familial adenomatous polyposis, osteomatous jaw and ocular lesions, several dental abnormalities, and an abdominal desmoid tumor are the characteristic features of this case. This case demonstrates the presence of unusual, widespread, hereditary, osteomatous jaw lesions that caused diagnostic confusion with familial gigantiform cementoma.

A novel mutation causing pseudohypoparathyroidism 1A with congenital hypothyroidism and osteoma cutis.

Various inactivating mutations in guanine nucleotide-binding protein, alpha-stimulating activity polypeptide1 (GNAS1) gene have been described with poor phenotype correlation. Pseudohypoparathyroidism type 1a (PHP1a) results from an inactivating mutation in the GNAS1 gene. Hormone resistance occurs not only to parathyroid hormone (PTH), but typically also to other hormones which signal via G protein coupled receptors including thyroid stimulating hormone (TSH), gonadotropins, and growth hormone releasing hormone. In addition, the phenotype of Albright hereditary osteodystrophy (AHO) is observed, which may include short stature, round facies, brachydactyly, obesity, ectopic soft tissue or dermal ossification (osteoma cutis) and psychomotor retardation with variable expression. We present a 2-year-old boy with PHP 1A who initially presented at age 3 weeks with congenital hypothyroidism. By 17 months of age, he manifested osteoma cutis, psychomotor retardation, obesity, brachydactyly and resistance to PTH with normocalcemia and mild hyperphosphatemia. Genetic analysis revealed a novel mutation in exon 13 of GNAS1 in our patient. This mutation, c.1100_1101insA, resulted in a frameshift and premature truncation of bases downstream. This mutation was also found in the mother of this patient who was also noted to have short stature, obesity, brachydactyly and non progressive osteoma cutis, but no hormone resistance.We report a novel heterozygous mutation causing PHP1A with PTH and TSH resistance and AHO which has not been described previously. PHP1A is also a rare presentation of congenital hypothyroidism.

Cutaneous and superficial soft tissue lesions associated with Albright hereditary osteodystrophy: clinicopathological and molecular genetic study of 4 cases, including a novel mutation of the GNAS gene.

Albright hereditary osteodystrophy is a rare syndrome, in which cutaneous and superficial soft tissue lesions traditionally include osteomas and calcifications. We report 4 patients from 2 families affected with Albright hereditary osteodystrophy and demonstrate that the spectrum of these cutaneous and soft tissue lesions is broader than is usually defined in the literature. In addition to osteomas in the dermis and subcutis, including so-called plaque-like osteoma, we identified the following lesions: calcifying aponeurotic fibroma-like lesion, calcinosis circumscripta-like lesion, and unusual nevi with osteoid and/or peculiar intranuclear pseudoinclusions. One osteoma and the calcifying aponeurotic fibroma-like lesion were analyzed by HUMARA and proved to be clonal. In a family, a novel mutation in the GNAS gene was also identified.

Diagnostic and mutational spectrum of progressive osseous heteroplasia (POH) and other forms of GNAS-based heterotopic ossification.

Progressive osseous heteroplasia (POH) is a rare, disabling disease of heterotopic ossification (HO) that progresses from skin and subcutaneous tissues into deep skeletal muscle. POH occurs in the absence of multiple developmental features of Albright hereditary osteodystrophy (AHO) or hormone resistance, clinical manifestations that are also associated with GNAS inactivation. However, occasional patients with AHO and pseudohypoparathyroidism 1a/c (PHP1a/c; AHO features plus hormone resistance) have also been described who have progressive HO. This study was undertaken to define the diagnostic and mutational spectrum of POH and progressive disorders of HO, and to distinguish them from related disorders in which HO remains confined to the skin and subcutaneous tissues. We reviewed the charts of 111 individuals who had cutaneous and subcutaneous ossification. All patients were assessed for eight characteristics: age of onset of HO, presence and location of HO, depth of HO, type of HO, progression of HO, features of AHO, PTH resistance, and GNAS mutation analysis. We found, based on clinical criteria, that POH and progressive HO syndromes are at the severe end of a phenotypic spectrum of GNAS-inactivating conditions associated with extra-skeletal ossification. While most individuals with superficial or progressive ossification had mutations in GNAS, there were no specific genotype-phenotype correlations that distinguished the more progressive forms of HO (e.g., POH) from the non-progressive forms (osteoma cutis, AHO, and PHP1a/c).

Osteoma of the calvaria in L-2-hydroxyglutaric aciduria.

L-2-Hydroxyglutaric aciduria (L-2-OHGA) is a rare autosomal recessive neurometabolic disease linked to chromosome 14q21.1 and is caused by mutations in the gene that most likely encodes L: -2-hydroxyglutarate dehydrogenase, which normally catalyses L: -2-hydroxyglutarate to alpha-ketoglutarate. It is characterized by progressive mental deterioration, pyramidal and cerebellar syndromes, macrocephaly and marked polycystic white-matter degeneration mainly involving frontal lobes. Brain tumours of variable nature have frequently been observed in L-2-OHGA. We report a patient affected by this disease who at the age of 20 years developed a bone tumour involving the right frontal region of the calvaria. He had first presented at the age of 10 years with psychomotor delay, clumsy gait and moderate mental impairment. Examination showed macrocephaly, cerebellar ataxia and quadripyramidal syndrome. Brain MRI showed low signal intensities on T1-weighted images and high signal intensities on T2-weighted images in cerebral subcortical white matter. Serum and urinary amino acid assay was normal. Urinary 2-hydroxyglutaric acid was 1418 mmol/mol creatinine (controls <25). Analysis of the L-2-hydroxyglutarate dehydrogenase gene revealed a homozygous mutation in exon 2 (A320G). At the age of 20 years, an osteoma of the right frontal bone was diagnosed. This finding reinforces the opinion concerning the association of L-2-OHGA and tumorigenesis and prompted us to verify the possible responsibility of some overproduced substances in this disease for the development of tumours and to look for any correlation between the type of mutation in the L-2-OHGA gene and the tumorigenic potential observed in some patients affected by this disease.

[A rare case of Gardner's syndrome complicated with rectal carcinoma].

Gardner's syndrome is a rare variant of the Familial Adenomatous Polyposis (FAP) in which affected individuals develop thousands of polyps within the gastrointestinal tract, with a 100 % risk of eventual malignant change. They also have a variety of extraintestinal abnormalities - various soft and hard tissues tumors like fibroma, osteoma, epidermoid cysts, sebaceous cysts on the scalp. Gardner's syndrome is an autosomal dominant disease, caused by mutations in APC ( adenomatous polyposis coli ) gene, which is located in chromosomal locus 5q21- q22. Firstly it has been described in 1953 by Gardner and Richards. They have investigated a family of 51 members with polyposis, some of them with multiple epidermoid cysts, fibromas and jaw osteomas. Eight of them have died by colorectal carcinoma. If undetected or untreated virtually all patients develop colonic carcinoma at a young age. Due to this high risk of malignancy the patients with Gardner's syndrome usually undergo surgical treatment by total or subtotal proctocolectomy. We report a case with Gardner's syndrome - a 36 year-old male who has been operated on in Department of Surgery in Vth city clinical hospital in October 2003. He had multiple adenomatous polyposis of colon, rectal cancer, osteomas of skull bones, subcutaneous fibromas and lipomas. We discovered also by ultrasound examination a polyp of gall bladder. His father has had also multiple polyposis with malignancy and metastatic lesions and he has died at age of 49 years. We performed total proctocolectomy with definitive iliac anus and cholecystectomy.