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Diagnosis: Ossifying fibroma of the maxilla presenting with associated sinusitis and orbital complications Ossifying fibroma is a benign fibro-osseous lesion that most commonly occurs in the bones of the craniofacial skeleton. Seventy-five percent of these lesions are found in the mandible.1,2 Ossifying fibroma of the maxilla is uncommon. Most diagnoses are made in the third or fourth decade of life, although onset can occur at any age. There is a slight predilection for women (female-male ratio, 1.6:1.0).3 Because of its expansile nature, ossifying fibroma clinically presents as jaw or facial asymmetry, displacement of teeth or hard palate, proptosis, nasal obstruction, or, rarely, sinusitis with or without eye pain.4 Grossly, ossifying fibromas are firm, gritty, gray, tan, or white masses usually ranging from 5 mm to 10 cm in diameter. Histopathologically, the lesions are composed of randomly distributed, osteoblast-lined (Figure 1, arrow), lamellar bone spicules within a background of fibrous stroma. The bone spicules are rarely completely mature. The fibrous stroma may be very cellular but is usually void of mitotic figures. Rapidly expansile masses (usually found in the paranasal sinuses and midface) may have secondary changes, including hemorrhage and inflammation.5 Figure 1. View LargeDownload Computed tomography reveals that ossifying fibroma is often heterogeneous and usually well circumscribed, with a thick or thin radiodense rim. Older lesions contain radio-opaque islands of bone within a soft tissue density. Early lesions usually lack these mineralized components.5 Expansile and aggressive ossifying fibromas of the midface may erode the wall of the maxillary sinus into the orbit or show reactive thickening of bone on CTs.4 There are many subtypes described in the literature: juvenile, aggressive, active, cementifying, and psammomatoid. Subtyping has no obvious prognostic value, and some authors advocate that it is probably the site of the tumor that is most significant. Midface and paranasal sinus lesions, regardless of histologic variance, seem to be more aggressive.6 The clinical, radiographic, and histopathologic differentiation of ossifying fibroma from fibrous dysplasia has historically presented a diagnostic challenge for surgeons, radiologists, and pathologists. Fibrous dysplasia is usually characterized clinically by slower growth.7 Radiographically, fibrous dysplasia can display radiolucent zones and diffuse areas of sclerosis. Similar to ossifying fibroma, fibrous dysplasia is heterogeneous on CTs but is surrounded only by a thin radiodense cortex.5 Chong and Tan4 describe a comprehensive method of histopathologic distinction between ossifying fibroma and fibrous dysplasia. Their 5 criteria include lesional circumscription, variability in tissue composition, presence of bone maturation from woven to lamellar, lack of consistent osteoblastic rimming, and configuration of bony trabeculae. With regard to lesional circumscription, ossifying fibroma is microscopically well demarcated from surrounding healthy bone by a fibrous capsule. Fibrous dysplasia merges with native bone at the periphery. Ossifying fibroma displays great variability in tissue composition from one microscopic field to another. One field may contain predominantly fibroblasts, whereas an adjacent area may be mostly bone. The bone–fibrous tissue ratio in fibrous dysplasia is relatively constant throughout the specimen. Ossifying fibroma usually contains mature lamellar bone interposed with woven bone, while the lamellar component is often missing from fibrous dysplasia.4,6 Generally, fibrous dysplasia lacks the consistent osteoblastic rimming of bony spicules that is seen in ossifying fibroma. Finally, configuration of bony trabeculae is often haphazard, forming odd geometric patterns (so-called Chinese characters) in fibrous dysplasia. Trabeculae are rounded, spherical, or ovoid in ossifying fibroma.4,5 Fibrous dysplasia and ossifying fibroma occasionally mimic each other with respect to rimming osteoblasts and presence or absence of lamellar bone. Without radiographic and clinical correlation, such lesions are designated benign fibro-osseous lesion, not further specified.5 Rarely, ossifying fibroma can occur in the ethmoid sinuses or maxilla.6 Neoplasms of this area can subsequently affect the orbit or paranasal sinuses, either by direct invasion or by disturbance of the osteomeatal complex, with stasis and infection in the dependent sinuses. The treatment of fibro-osseous lesions that cause acute sinusitis and orbital complications is multifaceted. Efforts should be taken to preserve vision by relieving elevated intraocular pressure, eradicating the infection, and correctly diagnosing and removing the expansile mass. Lateral canthotomy with cantholysis is a reliable method for decreasing elevated intraocular pressure caused by orbital hemorrhage. Many otolaryngologists prefer to decompress the orbit by incising the medial periorbita via an endoscopic transnasal approach. If an obstructing lesion prevents adequate transnasal exposure of the medial periorbita, lateral canthotomy with inferior cantholysis should be performed. Medical treatment of acute sinusitis with orbital complications in adults typically consists of intravenous antibiotics aimed at treating the usual pathogens implicated: Streptococcus pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, Haemophilus influenzae, and non–spore-forming anaerobes.8-10 Cultures obtained from purulent material can be negative for organisms up to 50% of the time.10 Treatment of ossifying fibroma is complete excision or aggressive curettage if complete excision is not possible without morbid disfigurement. Recurrence of midface lesions with incomplete excision has been reported to be as high as 28%.2 Treatment of fibrous dysplasia is traditionally less aggressive. Conservative debridement is indicated only if the fibrous dysplasia manifests compromised function, progression of deformity, pain, pathologic fracture, or malignant degeneration. Otherwise the patient is observed.5 Ossifying fibroma of the maxilla has the potential to encroach on adjacent structures, including the orbit and paranasal sinuses. The otolaryngologist must be able to synthesize the clinical, radiographic, and pathologic data to distinguish ossifying fibroma from fibrous dysplasia. The surgeon should be comfortable with both external and endoscopic approaches to the paranasal sinuses as well as with lateral canthotomy with inferior cantholysis when fibro-osseous lesions of the maxilla lead to orbital complications. Residents and fellows in otolaryngology are invited to submit quiz cases for this section and to write letters to the ARCHIVES commenting on cases presented. Quiz cases should follow the patterns established. See “Instructions for Authors.” Material for CLINICAL PROBLEM SOLVING: PATHOLOGY should be mailed to the Editor. Reprints are not available from the authors. References 1. Bradley ESLeake D Ossifying fibroma involving the maxilla and mandible. Oral Surg Oral Med Oral Pathol 1968;26605- 614PubMedGoogle ScholarCrossref 2. Eversole LRLeider ASNelson K Ossifying fibroma: a clinicopathologic study of sixty-four cases. Oral Surg Oral Med Oral Pathol 1985;60505- 511PubMedGoogle ScholarCrossref 3. Sciubba JJYounai F Ossifying fibroma of the mandible and maxilla: review of 18 cases. J Oral Pathol Med 1989;18315- 321PubMedGoogle ScholarCrossref 4. Chong VFTan LH Maxillary sinus ossifying fibroma. Am J Otolaryngol 1997;18419- 424PubMedGoogle ScholarCrossref 5. Wenig BMMafee MFGhosh L Imaging in ophthalmology, I: fibro-osseous, osseous, and cartilaginous lesions of the orbit and paraorbital region. Radiol Clin North Am 1998;361241- 1259PubMedGoogle ScholarCrossref 6. Commins DJTolley NSMilford CA Fibrous dysplasia and ossifying fibroma of the paranasal sinuses. J Laryngol Otol 1998;112964- 968PubMedGoogle ScholarCrossref 7. Slootweg PJ Maxillofacial fibro-osseous lesions: classification and differential diagnosis. Semin Diagn Pathol 1996;13104- 112PubMedGoogle Scholar 8. Kallings LO Bacteriological aspects of infection of the upper respiratory tract. Scand J Infect Dis Suppl 1983;399- 13PubMedGoogle Scholar 9. Lundberg CEngquist S Pathogenesis of maxillary sinusitis. Scand J Infect Dis Suppl 1983;3953- 55PubMedGoogle Scholar 10. Chang CHLai YHWang HZSu MYChang CWPeng CF Antibiotic treatment of orbital cellulitis: an analysis of pathogenic bacteria and bacterial susceptibility. J Ocul Pharmacol Ther 2000;1675- 79PubMedGoogle ScholarCrossref
Archives of Otolaryngology - Head & Neck Surgery – American Medical Association
Published: Mar 1, 2005
Keywords: maxilla,ossifying fibroma,sinusitis,osteofibrous dysplasia,jaffe-lichtenstein syndrome,osteitis fibrosa disseminata
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