Fibrous dysplasia of the temporal bone complicated by cholesteatoma and thrombophlebitis of the transverse and sigmoid sinuses: a case report.

Abstract

Fibrous dysplasia is a benign condition that can affect the skull and facial bones and cause a broad spectrum of otolaryngologic conditions. We present the case of a boy with polyostotic fibrous dysplasia with involvement of the temporal bone that was first diagnosed when he was 9-years old. His condition eventually became complicated by cholesteatoma and thrombophlebitis of the left transverse and sigmoid sinuses, and he died of his disease at the age of 19 years. We discuss these and other complications of fibrous dysplasia of the temporal bone and their management.

Introduction

Fibrous dysplasia is a disorder of unknown etiology in which normal bone is slowly replaced by abnormal fibrous tissue and irregularly arranged bony trabeculae. The condition frequently affects the skull and facial bones, and it can cause a broad spectrum of otolaryngologic conditions.

In a review of 269 patients with monostotic fibrous dysplasia, Nager and Holliday found craniofacial involvement in 31%. (1) Windolz reported that the more extensive the skeletal involvement is, as with severe polyostotic fibrous dysplasia, the more frequent and severe the involvement of the face and skull is. (2) Van Tilburg reviewed 144 patients with skull involvement and found that the most commonly involved bones were, in order of decreasing frequency, the frontal, sphenoid, ethmoid, parietal, temporal, and occipital bones. (3)

Pouwels and Cremers reported that approximately 18% of cases of cranio facial fibrous dysplasia involve the temporal bone. (4) Affected patients usually complain of conductive hearing loss and visible enlargement of the temporal bone. Other common complications of fibrous dysplasia of the temporal bone include cholesteatoma, erosion of vascular structures, compression of cranial nerves, and progressive narrowing of the internal and external auditory canals. Some of these complications can be life-threatening.

We present the case of a patient with polyostotic fibrous dysplasia with involvement of the temporal bone that became complicated by cholesteatoma and thrombophlebitis of the left transverse and sigmoid sinuses. We also discuss selected complications of fibrous dysplasia of the temporal bone and their management.

Case report

A boy of Vietnamese ancestry had first been seen at the age of 7 years for evaluation of decreased hearing in the left ear. He was found to have a conductive hearing loss with stenosis of the external auditory canal on the left. Computed tomography (CT) had demonstrated massive thickening of the left temporal bone, involvement of the basisphenoid bone, and expansion of the left side of the mandible.

At the age of 9 years, the patient developed a prominence on the left side of the skull with occlusion of the left ear canal and mild proptosis of the left eye without evidence of compressive optic neuropathy. Biopsy of the left mastoid cortex showed fibrous dysplasia.

The patient was subsequently followed by an otolaryngologist at a different facility. When he was 17 years old, CT and magnetic resonance imaging (MRI) revealed that the fibrous dysplasia involved the temporal, sphenoid, and parietal bones, with obliteration of the external auditory canal and mastoid air cells on the left. A T2-weighted MRI showed a 2-cm expansile lesion of abnormally high signal intensity in the left mastoid that extended into the middle ear space (figure 1).

At 18 years of age, the patient presented to the senior author's (J.B.F.) clinic with trismus and bleeding from theleft ear. Clinical examination revealed further enlargement of the left mastoid and mandible. Polypoid debris was removed from the left external auditory canal, and antibiotic packing was placed in the ear. At this time, the plan was to treat the patient with periodic local debridement and to obtain a new CT scan. However, the patient refused to undergo the imaging study.

Six months later, the patient was admitted emergently to the hospital with severe head and facial pain. His temperature was 101.2[degrees]F, and his white blood cell count was elevated. CT revealed extensive involvement of the left mastoid with obliteration of air spaces, expansion of the middle ear space, destruction of the sigmoid plate, an absence of the ossicles, and an irregular collection of gas near the left mastoid tip (figure 2). MRI obtained 2 days later showed a larger collection of gas in the mastoid and intense dural enhancement in the floor of the middle cranial fossa and the posterior fossa (figure 3). In addition, the left transverse sinus appeared thrombosed.

The patient's condition rapidly worsened despite aggressive medical therapy, and he died 6 days after admission at the age of 19 years. Autopsy revealed a bulging deformity of the left temporal bone and the calvarium, orbit, and mandible. Green, purulent material was found in the posterior fossa, and there was erythema and purulent material in the left transverse sinus. Bony destruction was noted in the inferior mastoid with red, granular, friable tissue consistent with a cholesteatoma. A probe could be passed from the posterior fossa to the external auditory canal.

[FIGURE 1 OMITTED]

Discussion

Fibrous dysplasia is categorized into three clinical subtypes--monostotic, polyostotic, and as a feature of McCune-Albright syndrome:

* Monostotic fibrous dysplasia accounts for approximately 70% of all cases, and it usually involves one of the long bones. (5)

[FIGURE 2 OMITTED]

[FIGURE 3 OMITTED]

* The polyostotic form, which occurs in approximately 30% of cases, involves more than one bone, often in the same limb; it has a predilection for the lower limbs. (5) Fibrous dysplasia of the upper limb is often associated with craniofacial involvement.

* Patients with McCune-Albright syndrome represent up to 3% of all cases of fibrous dysplasia. (5) This syndrome is characterized by the triad of polyostotic fibrous dysplasia, ipsilateral skin pigmentation, and precocious puberty. It occurs more often in young girls than boys.

Fibrous dysplasia affects the facial and neural cranium in 10 to 30% of cases of monostotic disease (2,6) and in 50 to 100% of cases of polyostotic disease. (2) Traditionally, fibrous dysplasia of the craniofacial bones has been classified as one of three types--pagetoid, sclerotic, or cystic--based on its radiographic appearance on plain films. In a review of 39 biopsy-proven cases, Fries found that 56% were pagetoid, 23% were sclerotic, and 21% were cystic. (6) Additionally, he noted that more than one radiographic form could exist simultaneously in the same patient. The pagetoid form of fibrous dysplasia may represent the end stage of sclerotic and cystic radiographic patterns. However, as Lustig et al (7) pointed out, the distinguishing features of these three types were originally based on plain radiographs, whereas the new radiographic standard for diagnosis and follow-up is CT.

Craniofacial fibrous dysplasia is usually described as having a ground-glass appearance on CT, with asymmetrical-involvement of the cranium and thinning of the cortical wall. (8) MRI is also useful, particularly for defining the extent of soft-tissue involvement. The affected bone typically exhibits intermediate to low signal intensity on T1-weighted imaging, intermediate to high intensity on T2-weighted imaging, and a heterogeneous enhancement after the administration of gadolinium. (9)

The definitive diagnosis of fibrous dysplasia is based on the fairly characteristic histopathologic findings. Grossly, the affected areas of bone appear as well-demarcated intramedullary lesions of varying size. The tissue consists of a vascular and moderately cellular proliferation of fibroblasts embedded with curvilinear trabeculae of woven bone that may mimic Chinese calligraphy. (5)

Craniofacial involvement of fibrous dysplasia affects the temporal bone in 18% of cases. (4) While most of these cases are unilateral, some cases of bilateral temporal bone involvement have been reported. (1,10-12) In a review of 53 cases of fibrous dysplasia of the temporal bone, Megerian and colleagues found that the most common presenting complaints were hearing loss, a mass in the temporal bone, unilateral otorrhea, and trismus. (12) Eighty percent of these patients had stenosis of the external auditory canal, and there was a correspondingly high rate of conductive hearing loss.

Fibrous dysplasia itself is a benign disease, but because of its expansile nature, it has the potential to cause severe morbidity and even death when it occurs in the craniofacial bones. Complications occur when the expanding bone mass occupies spaces, compresses structures, and/or exposes vulnerable anatomy. Enlargement of the temporal bone can also cause mechanical obstruction of the temporomandibular joint, which can result in trismus, obliteration of sinuses, blockage of the eustachian tube (leading to serous otitis media), and gradual obliteration of the external auditory canal (leading to conductive hearing loss). (1)

Sensorineural hearing loss secondary to involvement of the otic capsule or internal auditory canal is less common. (11) Dysplastic bone can compress the optic nerve, which can lead to blindness. Facial paralysis or paresis has been reported in 9% of reviewed cases. (12)

Cholesteatoma has been reported in 40% of patients with temporal bone fibrous dysplasia. (12) Cholesteatomas can themselves cause conductive or sensorineural hearing loss, labyrinthine fistula, facial paralysis, and intracranial infection. As the cholesteatoma expands, it can cause thrombophlebitis. In addition, exposure of the dura can lead to meningitis or lateral sinus thrombosis.

The classic presentation of lateral sinus thrombosis is one of high-spiking fevers (the so-called picket-fence pattern), fronto-occipital headache, earache, nausea, diplopia, and/or a loss of visual acuity. Common pathogens include Staphylococcus aureus, Streptococcus spp, and Escherichia coli, as well as gram-negative organisms and anaerobes in mixed infections. Additionally, Bacteroides fragilis has been reported as the most common organism in patients with lateral sinus thrombosis secondary to cholesteatoma. (13)

Fibrous dysplasia is usually managed conservatively with periodic radiographic surveillance unless cosmetic or functional impairment or complication occurs. Because the bony involvement is widespread, surgery is never curative. Radiation therapy has been abandoned as a treatment option because of its high association with malignant transformation. (14) In severe cosmetic deformity, surgical recontouring of dysplastic bone can be performed. In cases of severe canal stenosis, wide canalplasty can be performed. (15) When a cholesteatoma or an infectious complication has occurred, mastoidectomy must be performed. In lateral sinus thrombophlebitis, the sigmoid and transverse sinuses must be unroofed widely, the sinus opened, and the clot evacuated. Needle aspiration can be performed first if the presence of thrombosis is uncertain. Intravenous antibiotics are continued until the infection resolves clinically. The use of anticoagulation is controversial. (13)

In the case of our patient, the usual practice of periodic physical examinations and imaging surveillance was hampered by a number of factors. Difficulties with certain social and insurance issues led to sporadic follow-up during the 8 years that he was managed by another otolaryngologist. This case was further complicated by the fact that the cholesteatoma had not been recognized on CT and MRI at the time of the patient's hospital admission. This latter point illustrates the importance of good communication between otolaryngologists and interpreting radiologists; this includes ensuring the availability of a patient's pertinent history and previously obtained radiographic images. In retrospect, there was indeed radiographic evidence of the cholesteatoma 18 months before the patient's death; on the T2-weighted MRI, it appeared as an area of high signal intensity that was different from any other area of fibrodysplastic bone (figure 1). Detection of cholesteatoma may be difficult because the fibrodysplastic bone may also exhibit areas of bone loss with heterogeneous signal intensity.

As illustrated in this case, cholesteatoma can develop silently behind a stenotic external auditory canal. Unfortunately, the first manifestation of disease may be an intracranial complication. Once it develops, lateral sinus thrombosis may be lethal despite urgent surgical intervention.

In conclusion, fibrous dysplasia of the temporal bone is a rare condition that is most commonly associated with conductive hearing loss and enlargement of the temporal bone. Complications occur as a result of the expansile and obliterative nature of the disease process. When complete closure of the external canal occurs, surgery is indicated to prevent cholesteatoma and its potentially fatal complications. CT is helpful for following the progression of disease during conservative management.

Because pain is an uncommon symptom, complaints of headache, earache, or photophobia in a patient with cholesteatoma warrant further investigation to rule out thrombosis of the lateral sinus or other intracranial pathology. CT or MRI is therefore important for both surveillance of disease progression and planning for surgery. Uncomplicated cases of fibrous dysplasia of the temporal bone can be followed with CT or MRI every 6 to 12 months--or more often, depending on the clinical presentation. Because there can be subtle distinctions between fibrous dysplasia and complications such as a cholesteatoma, it is important for the reviewing radiologist to be skilled and to have previous films available for comparison.

A patient with a diagnosed cholesteatoma should undergo mastoidectomy. In addition, the presence of sinus thrombosis calls for intravenous antibiotics and immediate surgical intervention.

Acknowledgments

We thank Carlos R. Martinez, MD, and Patricia E. Roche, DO, for their assistance with the review of the imaging studies.

References

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(10.) Nager GT, Kennedy DW, Kopstein E. Fibrous dysplasia: A review of the disease and its manifestations in the temporal bone. Ann Otol Rhinol Laryngol Suppl 1982;92:1-52.

(11.) Morrissey DD, Talbot JM, Schleuning AJ II. Fibrous dysplasia of the temporal bone: Reversal of sensorineural hearing loss after decompression of the internal auditory canal. Laryngoscope 1997; 107(10):1336-40.

(12.) Megerian CA, Sofferman RA, McKenna MJ, et al. Fibrous dysplasia of the temporal bone: Ten new cases demonstrating the spectrum of otologic sequelae. Am J Otol 1995;16(4):408-19.

(13.) Syms MJ, Tsai PD, Holtel MR. Management of lateral sinus thrombosis. Laryngoscope 1999;109(10):1616-20.

(14.) Slow IN, Friedman EW. Osteogenic sarcoma arising in a preexisting fibrous dysplasia: Report of case. J Oral Surg 1971;29(2): 126-9.

(15.) Smouha EE, Edelstein DR, Parisier SC. Fibrous dysplasia involving the temporal bone: Report of three new cases. Am J Otol 1987;8(2): 103-7.

Rodrigo Martinez, MD; Jay B. Farrior, MD

From the Farrior Ear Clinic, Tampa, Fla.

Corresponding author: Jay B. Farrior, MD, Tampa Medical Tower, 2727 W. Martin Luther King Blvd., Suite 520, Tampa, FL 33607. Phone: [phone]; fax: [phone]; e-mail: [e-mail]