Journal of Indian Academy of Oral Medicine and Radiology

CASE REPORT
Year
: 2014  |  Volume : 26  |  Issue : 4  |  Page : 428--431

Craniometaphyseal dysplasia: A rare case in radiologic perspective


Simi Thankappan1, Sherin Nair2,  
1 Department of Oral Medicine and Radiology, Kothiwal Dental College, Moradabad, Uttar Pradesh, India
2 Department of Oral Pathology and Microbiology, Kothiwal Dental College, Moradabad, Uttar Pradesh, India

Correspondence Address:
Simi Thankappan
Department of Oral Medicine and Radiology, Kothiwal Dental College, Kanth Road, Moradabad - 244 001, Uttar Pradesh
India

Abstract

Craniometaphyseal dysplasia (CMD) is a very rare bone disorder of unknown etiology. It is characterized by sclerosis of the skull, craniofacial bones and even extremities. Although the exact etiology has not been understood, it is thought to be due to a mutation in the human ankylosis gene, ANKH. Here we report a case of a young male patient with extensive bony involvement. Radiographic examinations showed increased radiopacities of the maxilla and mandibular bones due to hyperostosis and sclerosis, and needed a detailed workup of bone dysplasias which made it a rare presentation for documentation.



How to cite this article:
Thankappan S, Nair S. Craniometaphyseal dysplasia: A rare case in radiologic perspective.J Indian Acad Oral Med Radiol 2014;26:428-431


How to cite this URL:
Thankappan S, Nair S. Craniometaphyseal dysplasia: A rare case in radiologic perspective. J Indian Acad Oral Med Radiol [serial online] 2014 [cited 2022 Jan 26 ];26:428-431
Available from: https://www.jiaomr.in/text.asp?2014/26/4/428/155638


Full Text

 Introduction



Craniometaphyseal dysplasia (CMD) is a very rare bone disorder not usually seen in a dental setup. It is characterized by sclerosis of bones, especially the skull base and craniofacial bones with generalized hyperostosis. The involvement of facial bones can mimic some commonly seen fibrosseous lesions in head and neck region, such as fibrous dysplasia, but the general involvement of long bones was a sign of a rare pathology.

 Case Report



A 22-year-old male patient, doing Bachelors in History, came to the department of Oral Medicine and Radiology with a complaint of a cavity in the left upper back tooth. The patient had gross facial deformity, mainly in the upper part of the face, and of the extremities. According to data obtained from anamnesis, the deformity started when he was about 7 years and several investigations had been done since then for this complaint. The deformity had been increasing slowly since detected. There was no family history of consanginous marriage, developmental milestones were normal and intelligence quotient was normal for his age. The extraoral findings included hypertelorism, frontal bossing, convergent squint, small nostril with thick bony wedge over the nasal bridge, prominent malar bones and bony thickening of the mandible, all contributing to features similar to leonine facies [Figure 1]. There was a progressive decrease in visual acuity, and bilateral sensorineural hearing loss, as confirmed by pure tone audiometry. There was no sign of facial nerve involvement. The intraoral findings included progressive spacing of teeth, class II division 2 malocclusion and a diffuse palatal swelling of size 4 × 3 cm as a result of hyperostosis of the palatine and the nasal bone [Figure 2]. Considering the unique facial features and sensory findings, a differential diagnosis of polyostotic fibrous dysplasia, osteopetrosis and rare congenital bone dysplasias were recorded, and chronic pulpitis of the left maxillary posterior second molar was diagnosed.{Figure 1}{Figure 2}

The carious left maxillary second molar tooth was to be examined radiogaphically for the purpose of root canal treatment, but the dense zygomatic bone in the region obscured the anatomy of the roots, which made it difficult to visualize the area. Postero-anterior (PA) view, lateral skull and panoramic radiographs were taken, and all radiographs showed sclerosis of the skull and the facial bones.

Plain and axial contrast computed tomographic (CT) scan of the head [Figure 3] showed evidence of thickening of all the calvarial bones with widening of the diploic spaces. The outer tables of the frontal, parietal, occipital and petrous temporal bone showed evidence of sclerosis. There was no evidence of sclerosis of the base of the skull and narrowing of basal foramina, but narrowing of foramen magnum was present. In the facial bones, sclerosis was present involving maxillary, zygomatic and nasal bones, nasal turbinates and nasal septum. The orbital cavity was smaller in size with increase in infraorbital distance. The visualized parts of the globe appeared normal. All the paranasal sinuses were normal, but there was inflammation of both maxillary sinuses. Normal pneumatization of mastoid air cells was present. All intracranial structures were normal.{Figure 3}

Plain radiographs of hands showed metaphyseal broadening with diaphyseal sclerosis. Plain radiographs of knee showed Erlenmeyer flask deformity. The CT diagnosis was craniometaphyseal dysplasia, correlating with the finding of Erlenmeyer flask deformity in the radiograph of the knee. Postero-anterior view, lateral skull and panoramic radiographs showed sclerosis of the skull and the facial bones, but there was no obliteration of the paranasal sinuses [Figure 4] and [Figure 5].{Figure 4}{Figure 5}

Magnetic resonance imaging (MRI) examination showed diffuse thickening of the lamina, transverse process and spinous process of all the vertebrae, causing cervical canal stenosis secondary to the dysplasia. Significant narrowing was seen at the C 3 -C 6 level, with contusion of spinal cord at C 4 -C 5 level. Serum chemistry showed an elevated alkaline phosphatase level (174 IU/L, normal being 35-104 IU/L).

Based on the history of onset of symptoms in early childhood, symptoms of cranial nerve involvement such as hearing loss and visual acuity, extraoral leonine facies and imaging findings in CT, MRI and plain radiographs of skull and extremities, polyostotic fibrous dysplasia and osteopetrosis were excluded. Plyes disease was ruled out due to the presence of cranial nerve involvement, and craniodiaphyseal dysplasia was ruled out due to involvement of metaphysis, and normal intelligence. Craniometaphyseal dysplasia was the final diagnosis.

Considering the normal intelligence and life expectancy, the prognosis was good, but the patient was counselled regarding cosmetic and functional surgical correction for which he was reluctant because of his educational commitments.

 Discussion



Craniometaphyseal dysplasia is a rare bone disorder of unknown etiology. It is characterized by sclerosis of the skull base, craniofacial bones with generalized hyperostosis, and abnormal remodeling of the metaphyses of the long bones, especially in the lower extremities. [1],[2] About 50-100 cases have been documented till now, [3] with minimal information on oral findings of the lesion like spacing of teeth, palatal swelling and difficulty in making radiographs due to the dense bones.

The term CMD was coined by Jackson et al. in 1954. [4] The etiology of CMD is thought to be mutations in the human ankylosis gene, ANKH. The ANKH gene encodes an amino acid protein, the progressive ankylosis protein homolog, which is a transmembrane protein located at the outer cell membrane, with the primary function of transport of intracellular pyrophosphate into the extracellular matrix. Pyrophosphate is a regulator of matrix bone mineralization. The ANKH mutation thus causes a reduced ability to transport intracellular pyrophosphate from osteoblasts to the bone matrix. [5]

Craniometaphyseal dysplasia is mainly of two types, autosomal dominant (Jackson type) and recessive type. In patients with dominant form, they have normal intelligence, stature, general health and the bony features include frontal and paranasal bossing and hypertelorism. The findings associated with bony overgrowth of the cranial foramina are cranial nerve paralysis, nystagmus, facial palsy, optic atrophy, and deafness. These findings are usually found to regress when the patient gets older. [6] Autosomal recessive conditions are similar to dominant ones, except that they are more severe and tends to get severe as age increases, with facial distortion and thick wedge of bone on the nasal bridge. [6],[7],[8] Dental findings include prognathic mandible, defective dentition, delayed eruption (a result of hyperostosis and sclerosis of alveolar bone), severe malocclusions, including anterior cross bite and deep bite. [4],[9]

Radiographic examinations showed increased radiopacities of the maxilla and mandibular bones due to hyperostosis and sclerosis. Other radiographic findings may be sclerosis of the skull base, vault, sclerosis of the petrous region of the temporal bone and facial bones leading to facial asymmetry, sclerosis along the skull sutures; obliteration of paranasal sinuses, and widening of the metaphyses of the long bones (described as Erlenmeyer flask or club-shaped deformity) [5] with thinned cortex and radiolucencies in the metaphyses, which can be detected early in life. [5],[10] Based on history of onset of symptoms in early childhood, symptoms of cranial nerve involvement, extraoral leonine facies and imaging findings in CT, MRI and plain radiographs of skull and extremities, a list of differential diagnosis list was narrowed out by excluding polyostotic fibrous dysplasia, osteopetrosis, Plyes disease and craniodiaphyseal dysplasia to diagnose the condition as craniometaphyseal dysplasia.

According to literature, management is extremely difficult which is either by medical or surgical method and none have yielded a satisfactory result. Calcitriol, low calcium intake, bisphosphonates and somatostatin is thought to influence the bone remodeling and has been tried but with varied results. Surgical results are also inconsistent and needs multidisciplinary treatment. [4],[10]

 Conclusion



Here we report a case of craniometaphyseal dysplasia in a young male patient with extensive involvement of skull and craniofacial bones and radiographic features showing severe sclerosis.

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