|Year : 2020 | Volume
| Issue : 3 | Page : 191-193
Adolescent temporal bone fibrous dysplasia
Johannas Mohd Yusof1, Jeyasakthy Saniasiaya1, Norhaslinda Ab Gani1, Goh Bee See2
1 Department of Otorhinolaryngology, Hospital Tuanku Ja'afar, Seremban, Negeri Sembilan, Malaysia
2 Department of Otorhinolaryngology Head and Neck Surgery, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia
|Date of Submission||06-Jun-2020|
|Date of Decision||18-Jun-2020|
|Date of Acceptance||24-Jun-2020|
|Date of Web Publication||22-Dec-2020|
Dr. Johannas Mohd Yusof
Department of Otorhinolaryngology, Hospital Tuanku Ja'afar, Jalan Rasah, 70300 Seremban, Negeri Sembilan
Source of Support: None, Conflict of Interest: None
Fibrous dysplasia (FD) is a rare, benign osseous tumor, whereby normal bone architecture is replaced by haphazard fibrous tissue. Temporal bone involvement is extremely rare and presents with vague symptoms. We present a case of temporal bone FD in an adolescent girl who presented with progressive unilateral hearing loss, which was successfully managed surgically with canal wall down mastoidectomy with no recurrence. FD although rare, has a tendency for cataclysmic complications if not discerned early.
Keywords: Fibrous dysplasia, mastoidectomy, temporal bone
|How to cite this article:|
Yusof JM, Saniasiaya J, Gani NA, See GB. Adolescent temporal bone fibrous dysplasia. Indian J Otol 2020;26:191-3
| Introduction|| |
Fibrous dysplasia (FD) is a rare, benign progressive bone disorder, described first by Lichtenstein and Jaffe. It is characterized by abnormal bone metabolism resulting in the production of weak, immature bone mixed in disorganized fashion with fibrous stroma. The condition has no gender predilection and a majority of lesions (75%) manifests by the age of 30 years. FD commonly involved the long bones, ribs, craniofacial bones, and the pelvis. Craniofacial bones are involved in approximately 10% of cases, and isolated temporal bone involvement is extremely rare. Patients with temporal bone FD habitually presents with headache (59%), followed by hearing loss (29%) in which 12% of these are conductive hearing loss. Secondary cholesteatoma from canal stenosis following FD has been reported. Temporal bone FD is managed mainly depending on the patient's presentation along with imaging findings. Although benign, the possibility of devastating and debilitating functional impairment warrants surgery in managing temporal bone FD.,
| Case Report|| |
A 15-year-old girl presented with gradually progressive reduced hearing over the left ear for about 6 months. She denied any associated otalgia, otorrhea, tinnitus, or vertigo. There was also no facial asymmetry. There was no recent trauma, fall, or upper respiratory symptoms.
On examination, the patient was well and comfortable. Otoscopic examination revealed a well-circumscribed firm mass occupying the entire left external ear canal, obscuring the tympanic membrane; the mass did not bleed on probing. The right external auditory canal and the tympanic membrane was normal. There was also mastoid swelling or tenderness and no facial nerve palsy. Pure tone audiometry showed left moderate conductive hearing loss with normal hearing on the right side.
High-resolution computed tomography (HRCT) temporal revealed heterogeneous expansile lesion, ground-glass opacity with its epicenter at the left mastoid temporal bone, extending into left external auditory canal causing erosion of the posterior bony canal [Figure 1]. The ossicles, bony facial canal, cochlea, and semicircular canal were otherwise normal.
|Figure 1: Axial cut of high-resolution computed tomography temporal shows heterogeneous lesion with its epicenter at the left mastoid temporal bone (arrow)|
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The patient was subjected to examination under anesthesia and biopsy. The histopathological examination revealed the presence of irregular-shaped woven bone trabeculae devoid of osteoblastic rimming separated by fibrous cells suggestive of FD [Figure 2]. After discussion with the parents, we proceeded with left modified radical mastoidectomy. Intraoperatively, the mass was seen occupying floor and posterior wall of bony canal, extending to the mastoid cavity and mastoid tip. The mass was noted to be enveloping the facial nerve near the stylomastoid foramen, and the facial nerve was exposed at the mastoid tip. The mesotympanum was not involved and ossicles were intact. The entire mass along with mastoid air cells was exteriorized.
|Figure 2: Photomicrograph showing tumor composed of the irregular shape of woven bone trabeculae devoid of osteoblastic rimming (black arrows), separated by bland fibrous cells (H and E, ×20)|
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Postoperatively, the patient was well with no complications. The patient was discharged home 2-days postsurgery with oral cefuroxime and analgesic. The patient was initially followed up at 2-weekly intervals for a month and subsequently monthly for review and aural toileting. Initial postoperative otoscopic findings noted granulation tissue over the mastoid cavity, which was managed conservatively. During her last follow-up at 3 months postoperative period, otoscopic findings showed no granulation tissue, well-epithelized mastoid cavity, and intact tympanic membrane. Repeated audiogram revealed no further deterioration, and she is planned for a conventional type of hearing aid.
| Discussion|| |
Three subgroups of FD have been distinguished: monostotic, polyostotic, and McCune-Albright syndrome. The monostotic form is the mildest as well as the most common subgroup;,, denotes nearly 70% of cases is normally diagnosed between 20 and 30 years. It involves ribs and craniofacial bones. The polyostotic form represents almost 30% of FD cases, is often diagnosed early amongst children, and tends to be more severe with prominent clinical manifestation involving the long bones and craniofacial region. Third is the McCune-Albright syndrome, which comprises 3% of cases commonly seen in females, is associated with short stature, endocrine abnormalities, and pigmented cutaneous lesion. Our patient discussed falls under the monostotic form.
Craniofacial FD comprises 10% of all FD cases. Temporal bone FD is extremely rare, more so in the pediatric population, as it only constitutes approximately 8-23% of all craniofacial and skull base FD., The common site of skull base FD includes ethmoid, sphenoid, and frontal bones. Common presentations of temporal bone FD in a child include external canal stenosis (62%), hearing loss (58%), and external skull deformity (38%). It is also noteworthy that, the occurrence of secondary cholesteatoma following FD has been extensively reported., In our patient, her chief complaint was progressive unilateral hearing loss. She also did not reveal any additional cutaneous or endocrine abnormality.
The diagnosis of FD is based on radiological and histopathological confirmation. Radiological investigation of choice in diagnosing this entity remains computed tomography (CT) following its superiority in defining bony details.,, Features of bony expansion, loss of normal corticomedullary definition as well as the presence of classical “ground-glass” radiopaque matrix found on CT scan is suggestive of FD. Furthermore, CT also can aid in differentiating FD from other skull base osteodystrophies such as otosclerosis, osteogenesis imperfecta, and Paget disease. Magnetic resonance imaging appearance of the other hand is less pathognomonic, with variability in signal intensity, depending on the degree of sclerosis, or lucency of the lesion. Histopathologically, the identifiable presence of irregular trabeculae of woven bone intermixed with fibrous connective tissue stroma,, as demonstrated in our case, confirms the diagnosis of FD.
In managing temporal bone FD in younger patients, there is a role for conservative management as the disease progression is usually slow and it is a benign condition. Surgery is recommended when the disease progression is noted to be aggressive or when significant cranial nerve palsies, cosmetic deformity, neurological symptoms, or debilitating condition as hearing loss is anticipated., The surgery, if possible, ought to be performed after puberty as FD, especially the monostotic form, has the tendency to become inactive and cease to progress after puberty. It is also noteworthy that the lower recurrence rate has been reported if surgery is done after skeletal maturity. Surgical options in temporal bone FD depends on the site of involvement. In our patient as FD involves mastoid bone with extension into the external auditory canal, a modified radical mastoidectomy was performed successfully with no evidence of recurrence to date.
| Conclusion|| |
Temporal bone FD although a benign disease may result in distressing and debilitating complications as chronic headache, hearing loss, tinnitus, and imbalance. HRCT temporal should be done in any suspicion of osteodystrophy of the skull base along with the histopathological evaluation of the entity. The decision whether to observe or treat the lesion surgically depends on the patient's age, clinical presentation, and extent of the disease.
Declaration of patient consent
The authors certify that appropriate guardian's consent have been obtained. It has been clearly stated and consented that the patient's clinical information and images are to be reported in the journal. The guardian understands that the patient's name and initials will not be published and all efforts will be made to maintain anonymity.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]