Osteoma

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For more information about osteoid osteoma that is not associated with sino-orbital osteoma, see osteoid osteoma

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Rohan A. Bhimani, M.B.B.S., D.N.B., M.Ch.[2]

Synonyms and keywords: Osteoma; Osteomata; Osteoncus; Ivory osteoma; Mature osteoma; Mixed osteoma; Homoplastic osteoma; Heteroplastic osteoma; Osteomas; Ivory exostosis; Sino-orbital osteoma; Sino-nasal osteoma; Paranasal sinus osteoma; Skull vault osteoma; Mandibular osteoma

Overview[edit | edit source]

Osteoma (also known as Osteomata) is a slow growing benign tumor of bone, occurring most commonly in the craniofacial skeletal structures, primarily in the nasal and paranasal (75-90%) sinuses. Osteoma arises from bone overgrowth, which is normally composed of connective tissue. Osteomas are slow growing tumors composed of compact or mature trabecular bone limited to craniofacial bones. Osteoma may be incidentally identified as a mass in the skull, mandible, or as the underlying cause of sinusitis or mucocele formation within the paranasal sinuses. When they are multiple, Gardner syndrome should be considered. Osteoma represents the most common benign neoplasm of the nose and paranasal sinuses. The causes remain uncertain, but commonly accepted theories propose embryologic, traumatic, or infectious causes. Osteomas are usually asymptomatic. Excision may be performed if osteoma is responsible for symptoms.

Historical Perspective[edit | edit source]

• In 1898, the description of craniofacial osteoma was first reported by Paul Schulze.^[1]
• In 1951, Eldon J. Gardner (1909–1989) a geneticist first described the occurrence of multiple osteomas in hereditary familial adenomatous polyposis (FAP).
• In 2014, The Lancet published an article named "Did René Descartes have a giant ethmoidal sinus osteoma?" the authenticity has been confirmed by anthropological and historical investigations to be true.^[2]

Classification[edit | edit source]

Osteoma can be classified based on imaging findings.

Enneking (MSTS) Staging System[edit | edit source]

• The Enneking surgical staging system (also known as the MSTS system) for benign musculoskeletal tumors based on radiographic characteristics of the tumor host margin.^[3]
• It is widely accepted and routinely used classification.

Pathophysiology[edit | edit source]

• The exact etiology of osteoma is unknown.^[4]
• The possibility of a reactive mechanism, triggered by trauma or infection, has been suggested.^[5]
• Osteoma arises from bone overgrowth, which is normally composed of connective tissue.^[6]
• Osteomas are slow growing tumors composed of compact or mature trabecular bone limited to craniofacial bones.
• Very rarely osteomas of the facial bones may be associated with Gardner's syndrome.
• Osteomas have a particular frequency distribution within the paranasal sinuses: frontal sinuses 80%, ethmoid air cells 15%, maxillary sinuses 5% and sphenoid sinus rare.

Genetics[edit | edit source]

• The hallmark of multiple osteomas is a mutation in the APC gene, that results in the Gardner syndrome.^[7]

Causes[edit | edit source]

• The cause of osteoma has not been identified.^[8]

Differentiating ((Page name)) from Other Diseases[edit | edit source]

Osteoma must be differentiated from other diseases that cause sinus or facial pain, headache, and changes to or loss of sense of smell, such as other osteogenic tumors, fibrous dysplasia, and chronic sinusitis.^[9][10]

Epidemiology and Demographics[edit | edit source]

• The prevalence of osteoma is approximately 3000 per 100,000 individuals worldwide.^[11]
• The incidence of osteoma remains unknown.
• Patients of all age groups may develop osteoma.
• The average patient age varies from 25 to 35 years.
• The mean age of the patients with osteoma is is 37 years.^[9]
• Men are more commonly affected than women, with a 3:1 ratio.^[12]
• There is no racial predilection to osteoma.

Risk Factors[edit | edit source]

There are no established risk factors for osteoma.^[6]

Screening[edit | edit source]

Screening for multiple osteomas is recommended among patients with family history or/and a confirmed diagnosis of Gardner syndrome. Thyroid exam and annual ultrasound, should be performed starting at age 10 to 12 years.^[13]

Natural History, Complications, and Prognosis[edit | edit source]

• If left untreated, osteoma progression occurs slowly and is then followed by facial distortion.^[14]
• Common complications of osteoma include:^[15]
  • Proptosis
  • Facial deformity
  • Airway obstruction
  • Sensory loss
  • Anosmia
  • Visual loss
• Prognosis is generally excellent,the lesion does not recur after surgical excision and it is not associated with malignant change.^[15]

Diagnosis[edit | edit source]

Diagnostic Study of Choice[edit | edit source]

Biopsy is the diagnostic study of choice for the diagnosis of osteoma.

• Gross appearance of osteoma include:
  • Osteomas have a spongy to densely appearance, conformed of in a polypoid and lobullated shape.[1]
  • The median size tumor size is 3.0 cm (range 0.5-8 cm).
  • Osteomas have a smooth surface and composed of dense compact bone (ivory osteoma), trabecular bone (mature osteoma, or both patterns).

• Histological appearance includes:
  • Presence of dense compact mature bone in paucicellular fibrous stroma.
  • Large trabeculae of mature lamellar bone can be also be seen.

History and Symptoms[edit | edit source]

• Small osteomas are asymptomatic and usually incidental findings.
• Common symotoms of osteoma include:^[16][17]
  • Headache
  • Nasal congestion
  • Facial pain
  • Facial tenderness
  • Loss of the sense of smell

Physical Examination[edit | edit source]

• Patients with osteoid osteoma usually appears well.
• Common physical examination findings of osteoid osteoma include:^[18]
  • Facial tenderness
  • Nasal obstruction and discharge
  • Tapping over a sinus area produces dull sound
  • Physical deformity over mastoid or facial area

Laboratory Findings[edit | edit source]

There are no diagnostic laboratory findings associated with osteoma.

Electrocardiogram[edit | edit source]

There are no ECG findings associated with osteoma.

X-ray[edit | edit source]

• Three views of affected bone or joint are recommended.^[19]
• Radiological findings for osteoma include:
  • Well circumscribed mass
  • Varying amounts of central lucency
  • Lobulated mass occupying frontal or maxillary sinus

Echocardiography or Ultrasound[edit | edit source]

There are no echocardiography/ultrasound findings associated with osteoma.

CT scan[edit | edit source]

• CT findings of osteoma include:^[20]
  • Well-circumscribed mass of variable density
  • Ground-glass appearance
  • Exophytical mass growing out of a sinus

MRI[edit | edit source]

• MRI findings of osteoma include:^[21]
  • Low signal on all sequences.
  • Mature osteomas may demonstrate some marrow signal, but are also predominantly low on all sequences

Other Imaging Findings[edit | edit source]

There are no other imaging findings associated with osteoma.

Other Diagnostic Studies[edit | edit source]

Nasal Endoscopy[edit | edit source]

Nasal endoscopy findings include:^[22]

• Direct visualization of the nasal passages structures, and sinuses.
• Tumor location, size, and adjacent structure evaluation.

Treatment[edit | edit source]

Medical Therapy[edit | edit source]

There is no medical treatment for osteoma; the mainstay of therapy is surgery.^[23]

Surgery[edit | edit source]

Surgery is the mainstay of treatment for osteoma.^[24][25]

Indication

• For symptomatic lesions, local excision is performed.

Types of Surgery

• Medial maxillectomy with a lateral rhinotomy
• Craniofacial resection
• Endoscopic resection

Recurrence Rare recurrence may occur after several years.

Primary Prevention[edit | edit source]

There are no established measures for the primary prevention of osteoma.

Secondary Prevention[edit | edit source]

There are no established measures for the secondary prevention of osteoma.

References[edit | edit source]

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