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Neurology India, Vol. 50, No. 3, Sept, 2002, pp. 374-375 Letter to the Editor Fibrous Dysplasia of the Temporal Bone S. Magu, D.S. Mishra, A.K. Sood*, N. Sharma Departments of Radiology and Medicine,* Pt. B.D. Sharma Postgraduate Instiutte of Medical Sciences, Rohtak - 124 001, Haryana, India. Code Number: ni02107 We would like to report a case of fibrous dysplasia of the temporal bone in a 15 year female, who presented with occipital headache for four months. On examination there was deviation of the angle of the mouth towards the right side and partial closure of the left eye while laughing. There was no impaired hearing. There was lower motor neurone palsy of the 7th cranial nerve on the left side with downgoing planters. Plain radiographs of the skull showed ground glass appearance of the temporal bone on the left side (Fig. 1, 2). Axial CT showed extensive involvement of the left temporal bone and mastoids by pagetoid fibrous dysplasia producing classic ground glass appearance. There is also extension of the process into the occipital bone, sphenoid bone and posterior cranial fossa. Fibrous dysplasia of bone is characterized by the presence of fibroosseous tissue in the interior of the affected part or parts of the bone and compress 2.5% of all osseous neoplasias and 7% of beningn tumors and occurs more frequent in female patients 2:1.1 Lichtenostein2 in 1938 coined the term fibrous dysplasia to describe a disorder characterized by the progressive replacement of normal bone elements by fibrous tissue. The disease can involve any bone in the body. In the head and neck, the skull and facial bones are involved in 10-25% of cases of monostotic fibrous dysplasia and in 50% of the polyostotic variety. Involvement of the temporal bone is relatively rare and only 53 cases have been reported.3 Fries4 described three patterns i.e. the pagetoid, sclerotic and cystic. The pagetoid pattern is the commonest and shows both sclerotic and radiolucent areas. Sclerotic lesions are homogenously dense whereas the cystic variety is characterized by a spherical and oval lucency surrounded by a dense bony shell. CT is the best way to display the bony changes while MR is useful in cystic fibrous dysplasia.3 Involvement of the auditory canal is the most common manifestation of fibrous dysplasia of the temporal bone seen in approximately 8% of patinets leading to a conductive hearing loss.5 Middle ear involvement is uncommon and results from secondary cholesteatoma from long standing external canal stenosis. Fibrous dysplasia may involve the oltic capsule, cochlea and labyrinth.5 Involvement of the inner ear may also encroach on the intratemporal facial nerve and facial nerve palsy may rarely be seen as seen in our cases. Patients suffering from fibrous dysplasia should be told of their problem and should be seen every three months for an indeterminate period of time, regarless of their age group.1 References
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