Ossifying Fibroma and Fibrous Dysplasia

Ossifying Fibroma

• Occurs in the third and fourth decades of life
• Slow-growing, asymptomatic, and expansile lesion
• Most commonly found in the mandibular premolar area
• Juvenile (aggressive) ossifying fibroma occurs in children and young adults, causing exophthalmos, proptosis, sinusitis, and nasal symptoms
• Composed of fibrous connective tissue with well-differentiated spindled fibroblast collagen fibers
• Radiographic features:
  • Well-circumscribed, sharply defined border
  • Unilocular or multilocular radiolucencies
• Differential diagnosis:
  • Fibrous dysplasia
  • Osteoblastoma
  • Focal cementoosseous dysplasia
  • Focal osteomyelitis
• Treatment and prognosis:
  • Curettage or enucleation
  • Recurrence after removal is rare

Fibrous Dysplasia

• Slow progressive enlargement of the affected jaw
• Usually painless and typically presents as a unilateral swelling
• Facial asymmetry
• Displacement of teeth
• Bone doesn't develop, doesn't mature
• Consists of a slight to moderate cellular fibrous connective tissue stroma that contains foci of irregularly shaped trabeculae of immature bone
• Radiographic features:
  • Ranges from a radiolucent lesion to a uniformly radiopaque mass
• Differential diagnosis:
  • Ossifying fibroma
  • Chronic osteomyelitis
• Treatment and prognosis:
  • Small lesions require no treatment
  • Large lesions require surgical recontouring
  • Malignant transformation treated with radiation therapy

Osteoblastoma

• Lesion measuring 1.5 cm
• Painful, not associated with facial asymmetry
• Most often found in young males
• Age onset is around puberty

Coronoid Hyperplasia

• Painless, not associated with facial asymmetry
• Most often found in young males
• Age onset is around puberty
• Two types:
  • Unilateral
  • Bilateral - results in limitation of mandibular movement, which is progressive over time; common type
• Bilateral type consists of mature hyperplastic bone, which may be partially covered by cartilaginous and fibrous connective tissue
• Radiographic features:
  • Unilateral type results in a misshapen or mushroom-shaped coronoid process on radiographs
• Differential diagnosis:
  • Osseous and chondroid neoplasms
• Treatment and prognosis:
  • Surgical excision
  • Rare recurrence

Malignant Non-Odontogenic Neoplasms of the Jaws

• Originate in the hard tissues and marrow cavity of the mandible and maxilla
• Subtypes:
  • Osteosarcoma
  • Chondrosarcoma
  • Ewing's sarcoma
  • Burkitt's Lymphoma
  • Plasma cell neoplasm
  • Metastatic carcinoma

Osteosarcoma

• Second most common primary bone tumor
• Site of origin:
  • Mandible
  • Maxilla
• Clinical features:
  • Swelling and localized pain
  • Loosening and displacement of teeth
  • Mandibular paresthesia (impingement of the inferior alveolar nerve)
  • Swelling and localized pain; maxillary paresthesia (impingement of the infraorbital nerve), epistaxis, nasal obstruction or eye problems
• Radiographic features:
  • Variable depending on the degree of calcification
• Histopathologic features:
  • Sarcomatous stroma directly producing tumor osteoid
  • Variable histologic patterns
  • More differentiated in the jaw than those in the skeleton, leading to a better prognosis
• Differential diagnosis:
  • Scleroderma (widening of the periodontal ligament space)
  • Chronic osteomyelitis, other malignancies, several benign neoplasms (moth-eaten radiographic appearance)
  • Pindborg tumor and metastatic carcinomas (sclerotic radiographic appearance)
  • Chondrosarcoma, fibrosarcoma of bone, aneurysmal bone cyst or giant cell tumor
• Treatment and prognosis:
  • Radical mandibulectomy or maxillectomy
  • Radiotherapy and chemotherapy for recurrences, soft tissue extension, and metastatic disease
  • Presurgical insertion of radium needles for mandibular osteosarcoma (76% 5-year survival rate)
• Prognosis:
  • Overall, 5-year survival for 35 to 40% of jaw osteosarcoma
  • Mandibular tumors have a better prognosis than maxillary tumors
  • Rarely metastasize to lymph nodes
  • Most common sites of metastasis: Lung and brain; 6 months' survival rate.
  • Local recurrences treated with surgical excision and chemotherapy

Multiple Myeloma

• Rarely seen before the fifth decade, with male predominance
• Asymptomatic or may cause pain, swelling expansion, numbness, mobility of the teeth, or pathologic fractures
• Soft tissue mass
• Weakness, weight loss, anemia, and hyperviscosity
• May develop systemic amyloidosis
• Radiographic features:
  • Variable
  • Punch-out appearance (non-corticated radiolucent area of bone) in the jaws and many of the hematopoietic marrow-containing bones of the skeleton
  • May be expansile and osteosclerotic
• Histopathologic features:
  • Monotonous proliferation of pure plasma cells
  • Wide range of differentiation from mature to less differentiated forms
• Differential diagnosis:
  • Metastatic carcinoma
  • Lymphoma
  • Idiopathic histiocytosis (LCD)
  • Carcinoma
  • Neuroblastoma
• Treatment and prognosis:
  • Chemotherapy with local radiation
  • Death due to infection, renal failure, disseminated myeloma, cardiac complications, hemorrhage or thrombosis
  • Poor prognosis for patients with severe azotemia, hypercalcemia, or anemia

Periapical Cyst

• Etiology: Periapical granuloma
• Most common cyst in the oral and perioral region
• Asymptomatic
• Causes bone resorption
• Associated with non-vital teeth
• Occurs at any age, peaks at the 3rd decade of life
• Commonly seen in the anterior maxillary and posterior mandibular regions
• Radiographic features:
  • Round to ovoid radiolucency with a narrow opaque margin that is continuous with the lamina dura
• Histopathologic features:
  • Lined by stratified squamous epithelium, polymorphonuclear leukocytes, and few lymphocytes
  • Epithelial lining are residues from the rest of Malassez
• Differential diagnosis:
  • Anterior region:
  • Posterior region:
• Treatment and prognosis:
  • Extraction and curettage of the apical zone
  • RCT with apicoectomy
  • Extraction only without curettage will lead to the development of a residual cyst that can weaken the bone

Lateral Periodontal Cyst

• Etiology: Dental lamina remnants within bone
• Adults older than 21 years, with male predilection
• Associated with vital teeth; non-mobile and may show root divergence
• Bluish discoloration when large (seen in the soft tissue as a bluish discoloration reflecting the fluid content)
• Location: Mandibular premolar and cuspid region, small soft tissue swelling within or slightly inferior to the interdental papilla
• Radiographic features:
  • Well-delineated, round or teardrop-shaped unilocular radiolucency between teeth
• Histopathologic features:
  • Lined by non-keratinized epithelium
  • With glycogen-containing clear cells
• Differential diagnosis:
  • Botryoid odontogenic cyst
  • Odontogenic keratocyst
  • Squamous odontogenic tumor
• Treatment and prognosis:
  • Extraction and curettage of the apical zone
  • RCT with apicoectomy

Botryoid Odontogenic Cyst

• Radiographic features:
  • Well-delineated, round or teardrop-shaped unilocular radiolucency between teeth
• Histopathologic features:
  • Multilocular cyst lined by thin stratified squamous epithelium
• Treatment and prognosis:
  • Enucleation is curative
  • No recurrence potential
  • Bone regeneration occurs over 6 months to 1 year
  • Root divergence normalizes, even without orthodontic tooth movement

Odontogenic Keratocyst

• Asymptomatic but can cause jaw expansion and tooth mobility if affected area
• Occurs at any age, peaking in the 2nd and 3rd decades
• Occurs in children as part of basal cell nevus syndrome
• Commonly affects the posterior portion of the body of the ramus of the mandible and the maxillary canine and 3rd molar areas
• Two basic types:
  • Parakeratinized odontogenic keratocyst: Found in the anterior part of the mandible.
  • Orthokeratinized odontogenic keratocyst: Found in the posterior part of the mandible.
• Radiographic features:
  • Well-circumscribed radiolucency with a smooth radiopaque rim
• Histopathologic features:
  • Keratinizing odontogenic cyst showing orthokeratin, a granular cell layer, and flattened basal cells
  • Typical odontogenic keratocyst shows parakeratinized corrugated surface, hyperchromatic palisaded basal cells.
• Differential diagnosis:
  • Dentigerous cyst
  • Adenomatoid odontogenic cyst
  • Ameloblastoma
  • Lateral periodontal cyst
  • Residual cyst
• Treatment and prognosis:
  • Marsupialization and an unerupted tooth that is associated with the cyst is guided into the arch
  • Enucleation and curettage for small cysts
  • Resection for large multilocular keratocyst
  • Resection for multiple recurrences after enucleation and curettage

Calcifying Odontogenic Cyst

• Originates from odontogenic epithelial remnants within the gingival area of either jaw
• Location: Maxilla
• Peak: 2nd decade, individuals younger than 40
• Female predilection
• Expansion of alveolar bone or soft tissues
• Absence of tenderness
• Radiographic features:
  • Unilocular or multilocular radiolucency
  • Opacities may produce a "salt and pepper" type of pattern
• Histopathologic features:
  • Ghost cell keratinization is a characteristic microscopic feature
  • Well-delineated cystic proliferation with a fibrous CT wall
• Differential diagnosis:
  • Calcifying epithelial odontogenic tumor
  • Peripheral ossifying fibroma
  • Adenomatoid odontogenic tumor
• Treatment and prognosis:
  • Enucleation with no recurrence potential

Globulomaxillary Cyst

• Nonspecific designation for any lesion in the globulomaxillary area (between maxillary lateral incisor and canine)
• Inverted pear-shaped radiolucency
• Asymptomatic, teeth are vital, divergence of roots
• Treatment and prognosis:
  • Treatment is usually surgical enucleation