Craniodiaphyseal dysplasia (CDD) is a rare sclerotic bone disorder with a variable phenotypic expression. It has been described in less than 20 cases in the literature. Massive generalized hyperostosis and sclerosis, particularly of the skull and facial bones, may lead to severe deformity. The clinical course is typically characterized by progressive calvarial thickness, encroachment of the craniofacial foramina and brain by the relentless deposition of bone. Compression of cranial nerves, the foramen magnum, and intracranial contents commonly leads to blindness, loss of hearing, facial diplegia, epilepsy, and mental retardation. Stenosis of the cervical canal may lead to quadriparesis as a late complication of hyperostosis. The long bones show hyperostosis and sclerosis of the expanded diaphyses, and sometimes a modelling defect in the metaphyses. The ribs, clavicles, and pelvis may show some degree of sclerosis and defective modelling, but are less severely involved. Histopathology of bones show increased numbers of osteoblasts, and biopsies of parietal bones show that the air spaces of the mastoid, external auditory canal, and middle ear cavity may be reduced by hyperostotic bone. The ossicles may be deformed by the bony overgrowth. Anomalous ossicles with hyperostosis could affect the air conduction. Facial nerves dysfunction could result from mechanical damage of the nerve fibers and/or impaired vascular supply by the hyperostosis. Nasolacrimal obstruction often occurs. Most described cases of CDD were sporadic, but one case of apparent recessive condition has been reported, in a mother and her daughter with greater degree of hyperostosis and sclerosis than that described for other patients with craniodiaphyseal dysplasia, and significant metaphyseal involvement. Mutation analysis of the TGFB1 gene allows excluding the diagnosis of Camurati-Engelmann disease. Close observation is mandatory to manage further progression of the disease, and magnetic resonance imaging should be a routine component of the evaluation of these patients. Surgery is to be performed in most cases at some stage of the disease, keeping in mind that patients with CDD present problems to the anaesthetist, specifically difficulties with airway management and tracheal intubation. Significant brain compression with signs and symptoms of increased intracranial pressure must be managed by decompressing craniectomy enlarging the anterior and middle fossae. Benefits from choanal stenosis surgery, craniofacial remodelling and dacryocystorhinostomy are usually short-lived. Orbital and optic nerve decompression may be necessary in case of papilledema. However, reconstitution of osseous optic canals is rather rapid, and papilledema may return. Long-term treatment rests in the control of rapid abnormal bone formation. Calcitriol/calcitonin therapy with a low calcium diet or prednisone may alter the clinical course of progression. Early recognition is crucial in these conditions as therapy directed at the underlying bony defect has the best chance of success if initiated in infancy.
Last update: October 2004