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We report an 18-year-old male with multiple exostoses, dysmorphic features, mental retardation and myopathy. The case is discussed in the light of previously reported disorders in which multiple exostoses are associated with neurological impairment.
We report pre- and post-operative three-dimensional (3D)-spiral CT images in a patient with multiple exostoses. Images of 3D-CT, which were performed using the integrated 3D software of the CT system, showed the exact shapes and locations of the individual tumors around the knee joint in comparison with the surgical findings and resected specimen. 3D-spiral CT images of multiple exostoses would be useful for the planning of surgical procedure.
Exostoses of the maxilla and mandible are nodular protuberances of mature bone that need to be accurately distinguished from other more diagnostically significant lesions, notably exosteal osteomas. Multiple dermatofibromas are rare and may be associated with altered immune function. We report the case of an otherwise healthy 47-year-old woman who was first seen with multiple maxillary and mandibular exostoses associated with multiple dermatofibromas. This association has not been previously reported.
An incidental post-mortem finding is reported. Its clinical relevance is discussed. It is suggested that some EAC exostoses may have a similar origin and thus an association with IAC exostoses.
Hereditary multiple exostoses is an autosomal dominant disorder that is characterized by short stature and multiple, benign bone tumours. In a majority of families, the genetic defect (EXT1) is linked to the Langer-Giedion syndrome chromosomal region in 8q24.1. From this region we have cloned and characterized a cDNA which spans chromosomal breakpoints previously identified in two multiple exostoses patients. Furthermore, the gene harbours frameshift mutations in affected members of two EXT1 families. The cDNA has a coding region of 2,238 bp with no apparent homology to other known gene sequences and thus its function remains elusive. However, recent studies in sporadic and exostosis-derived chondrosarcomas suggest that the 8q24.1-encoded EXT1 gene may have tumour suppressor function.
Bony exostosis (BE) is described as a benign localised overgrowth of bone of unknown aetiology. Buccal bony exostosis (BBE) development secondary to soft tissue graft procedures has been reported in a small number of cases. The dental literature describes BBE development also at sites where free gingival grafts (FGG) have been used to increase the amount of gingiva. The following case series describes BBE development at nine sites (five cases) at which FGG was performed to increase the width of the attached gingiva. The presence of exostoses has been recognised during postoperative visits. Histological examination revealed osseous enlargements compatible with the diagnosis of exostoses at two re-entry procedures. In conclusion, based on previous reports, periosteal trauma, eg fenestration, seems to be the main aetiologic agent associated with the development of BBE in areas where FGG were placed.
STUDY DESIGN: Case report of a severe upper cervical cord compression and tetraparesis by a massive cervical exostotic osteochondroma in a patient with multiple exostoses-mental retardation syndrome (Langer-Giedion syndrome; LGS). OBJECTIVE: To describe this very rare pathological condition and the results of surgical intervention. SETTING: Gifu, Japan. METHODS: A 23-year-old man was referred to our clinic because of progressing tetraparesis. He had previously been diagnosed with hereditary multiple exostoses and mental retardation. As he had not complained of any symptoms, his family only noticed the tetraparesis after advanced deterioration. His face possessed the pathognomic features of LGS. A postmyelogram CT scan demonstrated an exostotic mass arising from the left-side C2 pedicle with associated severe spinal cord compression. He was diagnosed with LGS. Hemilaminectomy on the left side and resection of the osteochondroma were performed. RESULTS: At 5 years postoperatively, a neurological examination showed the full return of all motor functions. The CT scan revealed no intracanalar recurrence of the tumor. CONCLUSION: In this case of severe tetraparesis due to cervical osteochondroma, decompression by hemilaminectomy provided excellent results. In patients with LGS and intracanalar osteochondroma, the neurological deficit may be masked by mental retardation. Hence, awareness of this pathological condition will help clinicians diagnose it at an early stage.
The cases of 2 children (9 and 11 years old) with hereditary multiple exostoses disease are presented. The lesions were located primarily in the acetabular fossa of the left hip and caused pain and limitation of range of motion. Hip arthroscopy was performed to remove the exostoses without damaging the articular surfaces and the Y cartilage. After the procedure, the pain disappeared and normal range of motion was recovered for both children. Conventional surgery would have required hip dislocation to access these lesions with an increased risk of femoral head necrosis. These cases constitute a new and interesting application of hip arthroscopy.
Multiple cartilaginous exostoses were found in a 41-year-old man and his two sons, aged 11 and 15 years. The older boy had extensive polyposis of the sigmoid colon and gastric antrum, his brother had radiological changes suspicious of sigmoid polyposis, while there was no radiological evidence of polyposis in the father. None of them had any symptoms of polyposis. The described combination of findings suggests a separate entity from Gardner's syndrome, perhaps on the basis of a combined dominant gene inheritance. In case of multiple exostoses radiological and endoscopic examination of the gastro-intestinal tract for polyposis are indicated.
On the basis of follow-up examinations it was found that exostoses at the distal ulna often result in shortening of the ulna and curvation of the radius. The resulting deformation of the wrist joint is particularly common in girls with exostoses which are over 7 mm wide and affect the ulnar epiphyseal cartilage. Particularly in the period of growth before puberty the progress of the deformation is considerable. Thus, female patients of group 3 in particular have to be examined carefully; in many cases surgery is necessary, in order to prevent further deformation and possibly even destruction of the radio-ulnar joint.
OBJECTIVE: The study goal was to demonstrate the prevalence and severity of external auditory exostoses (EAEs) in a population of surfers and to examine the relationship between these lesions and the length of time surfed as well as water temperature in which the swimmers surfed. It was hypothesized that subjects who predominantly surfed in colder waters had more frequent and more severe exostoses. METHODS: Two hundred two avid surfers (91% male and 9% female, median age 17 years) were included in the study. EAEs were graded based on the extent of external auditory canal patency; grades of normal (100% patency), mild (66% to 99% patency), and moderate-severe (<66% patency) were assigned. Otoscopic findings were correlated with data collected via questionnaires that detailed surfing habits. RESULTS: There was a 38% overall prevalence of EAEs, with 69% of lesions graded as mild and 31% graded as moderate-severe. Professional surfers (odds ratio 3.8) and those subjects who surfed predominantly in colder waters (odds ratio 5.8) were found to be at a significantly increased risk for the development of EAEs. The number of years surfed was also found to be significant, increasing one's risk for developing an exostosis by 12% per year and for developing more severe lesions by 10% per year. Individuals who had moderate-severe EAEs were significantly more likely to be willing to surf in colder waters than were those who had mild EAEs (odds ratio 4.3). CONCLUSIONS: EAEs are more prevalent in cold water surfers, and additional years surfing increase one's risk not only for developing an EAE but also for developing more severe lesions.
Hereditary multiple exostoses (HME) is an autosomal dominant disorder characterized by the presence of multiple exostoses. Three genetic loci have been identified, of which two (EXT1 and EXT2) have tumor suppressor activity. HME greatly increases the risk to develop sarcoma in the dysplastic tissue. The authors report an 8-year-old girl with HME who developed acute myeloblastic leukemia.
Hereditary multiple exostoses (HME), the most frequent of all skeletal dysplasias, is an autosomal dominant disorder characterized by the presence of multiple exostoses localized mainly at the end of long bones. HME is genetically heterogeneous, with at least three loci, on 8q24.1 (EXT1), 11p11-p13 (EXT2), and 19p (EXT3). Both the EXT1 and EXT2 genes have been cloned recently and define a new family of potential tumor suppressor genes. This is the first study in which mutation screening has been performed for both the EXT1 and EXT2 genes prior to any linkage analysis. We have screened 17 probands with the HME phenotype, for alterations in all translated exons and flanking intronic sequences, in the EXT1 and EXT2 genes, by conformation-sensitive gel electrophoresis. We found the disease-causing mutation in 12 families (70%), 7 (41%) of which have EXT1 mutations and 5 (29%) EXT2 mutations. Together with the previously described 1-bp deletion in exon 6, which is present in 2 of our families, we report five new mutations in EXT1. Two are missense mutations in exon 2 (G339D and R340C), and the other three alterations (a nonsense mutation, a frameshift, and a splicing mutation) are likely to result in truncated nonfunctional proteins. Four new mutations are described in EXT2. A missense mutation (D227N) was found in 2 different families; the other three alterations (two nonsense mutations and one frameshift mutation) lead directly or indirectly to premature stop codons. The missense mutations in EXT1 and EXT2 may pinpoint crucial domains in both proteins and therefore give clues for the understanding of the pathophysiology of this skeletal disorder.
Hereditary multiple exostoses (EXT) is an autosomal dominant disorder of enchondral bone formation characterized by multiple bony outgrowths (exostoses), with progression to osteosarcoma in a minority of cases. The exclusive involvement of skeletal abnormalities distinguishes EXT from the clinically more complex Langer-Giedion syndrome (LGS), which is associated with deletions at chromosome 8q24. Previously, linkage analysis has revealed a locus for EXT in the LGS region on chromosome 8q24. However, locus heterogeneity was apparent with 30% of the families being unlinked to 8q24. We report on two large pedigrees segregating EXT in which linkage to the LGS region was excluded. To localize the EXT gene(s) in these families we performed a genome search including 254 microsatellite markers dispersed over all autosomes and the X chromosome. In both families evidence was obtained for linkage to markers from the proximal short and long arms of chromosome 11. Two-point analysis gave the highest lod score for D11S554 (Zmax = 7.148 at theta = 0.03). Multipoint analysis indicated a map position for the EXT gene between D11S905 and D11S916, with a peak multipoint lod score of 8.10 at 6 cM from D11S935. The assignment of a second locus for EXT to the pericentromeric region of chromosome 11 implicates an area that is particularly rich in genes responsible for developmental abnormalities and neoplasia.
An X;8 translocation was identified in a 27-year-old female patient manifesting multiple exostoses and autism accompanied by mental retardation and epilepsy. Through molecular analysis using yeast artificial chromosomes (YACs) and cosmid clones, the translocation breakpoint was isolated and confirmed to be reciprocal within a 5'-GGCA-3' sequence found on both X and 8 chromosomes without gain or loss of a single nucleotide. The translocation breakpoint on the X chromosome occurred in the first intron of the gastrin-releasing peptide receptor (GRPR) gene and that on chromosome 8 occurred approximately 30 kb distal to the 3' end of the Syndecan-2 gene (SDC2), also known as human heparan sulfate proteoglycan or fibroglycan. The GRPR gene was shown to escape X-inactivation. A dosage effect of the GRPR and a position effect of the SDC2 gene may, however, contribute the phenotype observed in this patient since the orientation of these genes with respect to the translocation was incompatible with the formation of a fusion gene. Investigation of mutations in these two genes in unrelated patients with either autism or multiple exostoses as well as linkage and association studies is needed to validate them as candidate genes.
Hereditary multiple exostoses (HME) is an autosomal dominant condition in which bony outgrowths occur from the juxtaepiphyseal regions of the long bones. In a few percent of cases these exostoses undergo malignant transformation to chondrosarcomas. HME results from mutations in one of two homologous genes, EXT1 and EXT2. These are members of a new gene family that is conserved from Caenorhabditis elegans to higher vertebrates. In humans this family comprises five genes which are most conserved at their C-termini, but they do not contain any discernible functional motifs and their function(s) is unclear. Indirect evidence suggests that EXT proteins are involved in glycosaminoglycan synthesis, act as tumor suppressors and affect hedgehog signaling. One recent study has also reported that these proteins co-purify with glycosyltransferase (GlcA and GlcNAc transferase) activity and on that basis it has been postulated that they are themselves glycosyl-transferases. We performed two-hybrid screens with a fragment of EXT2 from the region that is most highly conserved in the gene family and identified two interacting proteins: the tumor necrosis factor type 1 associated protein and a novel UDP-GalNAc:poly-peptide N -acetylgalactosaminyltransferase. Significantly, both these interactions were abrogated by a disease-causing EXT mutation, indicating that they are important in the etiology of HME. The EXT2-GalNAc-T5 interaction provides the first direct physical link between EXT proteins and known components of glycosamino-glycan synthesis.
A 17-year-old girl with hereditary multiple exostoses, who was thought to have malignant transformation of an exostotic lesion, was examined by bone and Tl-201 chloride scintigraphy. Scintigraphy showed markedly intense uptake by the lesion, whereas Tl-201 imaging did not. Bone scintigraphy revealed intense to moderate uptake in other exostotic lesions, but none was apparent on the Tl-201 study. The lesion was resected and the histopathologic diagnosis was osteochondroma. Negative findings of Tl-201 scintigraphy may not exclude the possibility of chondrosarcoma, and the utility of this method may be limited. However, Tl-201 scintigraphy appears to have a useful role in differentiating malignant transformation from benign osteochondroma in hereditary multiple exostoses.
A case of hereditary multiple exostoses with acute cervical myelopathy, tetraplegia, and apnea is reported. Neurological complications as a result of osteochondromas in hereditary multiple exostoses are rare. The majority of osteochondromas in the cervical spine arise from the neural arch. Magnetic resonance imaging and computed tomography are invaluable in localizing the origin of the lesion and its relationship to the spinal cord. Decompressive laminectomy usually results in excellent functional recovery. Where significant dorsal spinal cord compression exists without neurological deficit, prophylactic decompression can be recommended.