Fibro Osseous Lesions

Fibro Osseous Lesions

• 1.
  FIBRO-OSSEOUS LESIONS “Theterm fibro-osseous lesion (FOL) is a generic designation of a group of jaw disorders” characterized by the replacement of bone by a benign connective tissue matrix. This matrix displays varying degrees of mineralization in the form of woven bone or of cementum-like round acellular intensely basophilic structures.
• 2.
  Classification Charles WaldronClassification Of The Fibro-Osseous Lesions Of The Jaws (1985) 1. Fibrous Dysplasia a. Monostotic b. Polyostotic 2. Fibro-Osseous (Cemental) Lesions Presumably Arising In The Periodontal Ligament a. Periapical Cemental Dysplasia b. Localized Fibro-Osseous-Cemental Lesions (Probably Reactive In Nature) c. Florid Cement-Osseous Dysplasia (Gigantiform Cementoma) d. Ossifying & Cemenifying Fibroma 3. Fibro-Osseous Neoplasms Of Uncertain Or Detectable Relationship To Those Arising In The Periodontal Ligament (Category II) a. Cemetoblastoma, Osteoblastoma & Osteoid Osteoma b. Juvenile Active Ossifying Fibroma & Other So Called Aggressive, Active Ossifying /Cementifying Fibromas.
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  Eversole Classification, 2008
• 4.
   By definition,all benign fibro-osseous lesions possess an osseous and fibrous tissue component.
• 5.
   The ossificationsin BFOL can be quite heterogeneous even within a specific disease entity.  Newly formed bone - woven pattern of collagen fiber orientation.  Mature bone - lamellar pattern.  Many have both irregular trabeculae as well as spheroidal cementicle calcifications, so called “ Cemento-ossifying” lesions.
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   The ossificationpatterns represent the “age” of the lesion. Early stages- more cellular and osteoblastic rimming of trabeculae is more prominent. Older lesions - stroma is more mature.
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  FIBROUS DYSPLASIA Lichtenstein,1938  It is a disease of bone maturation and remodeling in which the normal medullary bone and cortices are replaced by a disorganized fibrous woven bone.  The resultant fibro-osseous bone is more elastic and structurally weaker than the original bone.  Caused by postzygotic mutation in the GNAS1 gene.  Mutations of the GSa gene  No hereditary influence.
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  Investigation of theGSa gene in the diagnosis of fibrous dysplasia  Done by direct sequencing of the Gsa gene.  High prevalence of GSa gene mutations in fibrous dysplasia. Int. J. Oral Maxillofac. Surg. 2004; 33: 498–501 Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;111:618- 626
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  Types of FibrousDysplasia Forms of presentation of fibrous dysplasia Bone Involvement Single Multiple Cafἐ au Lait Spots Endocrine disorders Soft-tissues masses Monostotic X Polyostotic X McCune Albright Syndrome X X X Mazabrau d disease X X
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   If themutation occurs during early embryologic life Multiple bone lesions, Cutaneous pigmentation and endocrine disturbances
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   If themutation occurs during later stages Multiple bone lesions  If the mutation occurs during postnatal life Affects single bone
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  Monostotic Fibrous Dysplasia  Limited to a single bone.  Accounts for 80% to 85% of all cases  M:F = 1:1  Painless swelling.  Growth is generally slow but occasionally rapid.  Maxilla > Mandible.  60% of cases causes displacement of mandibular canal.  Often detected during the first two decades of life. Fibro-osseous Iesions of the jaws. J Oral MaxilIofac Surg 43:249, 1985
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   Mandibular lesionsare truly monostotic.  Maxillary lesions often involve adjacent bones(e.g., zygoma, sphenoid, occipital) Craniofacial Fibrous Dysplasia.
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  Polyostotic Fibrous dysplasia; Jaffe-Lichtenstein Syndrome; McCune – Albright Syndrome  Involvement of two or more bones.  When seen with cafἐ au lait pigmentation  Jaffe- Lichtenstein syndrome.  Polyostotic fibrous dysplasia + cafἐ au lait pigmentation + multiple endocrinopathies  McCune Albright Syndrome.
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   Causes facialasymmetry.  Pathologic fractures with pain and deformity.  Leg length discrepency is common due to involvement of upper portion of the femur ( Hockey Stick deformity).
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  Radiographic Features Depends upon the stage of the disease.  Early onset lesions are radiolucent and later progressively calcify, culminating in a “Ground Glass” or Mottled Mixed radiolucent/ radiopaque pattern.  Critical feature to diagnosis- FD fails to manifest any discreate margins; rather, the lesional bone subtly blends into the surrounding normal appearing
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  Histopathology  Earlyformative phase, pronounced osteogenesis is seen with thin osteoid anastomosing trabeculae that are rimmed with osteoblast. Stromal fibroblastic element - proliferative and hypercellular, no pleomorphism. With time, trabeculae thicken and osseous collagen pattern remain woven and the trabeculae assume the classic
• 19.
   Long-standing polyostoticFD is sarcomatous , which can occur in absence of radiation therapy.  Most frequent site - craniofacial skeleton.  Differentiating features on radiograph between sarcoma and FD are: ◦ Permeative ill-defined borders, ◦ Destroyed cortical outline and/or spiculated periosteal new bone formation ◦ Periodontal ligament space widening.
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  Malignant Transformation of FD:  Occur in <1% of the cases. Osteosarcoma is the most common histologic type, followed by fibrosarcoma, chondrosarcoma, and malignant fibrohistiocytoma. Most common in the maxilla and mandible  Calvarium – rare involvement. Spontaneous Conversion of Fibrous Dysplasia Into Osteosarcoma(J Craniofac Surg 2011;22: 959 -961)
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  Treatment and Prognosis  Timing of intervention is based on the symptoms manifesting as a result of the disease.  Recommended treatment options can be divided into 4 categories: 1. Observation 2. Medical therapy 3. Surgical remodelling 4. Radical excision and reconstruction
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  1. Observation: Monitoring is through serial radiographs, CT scans, and clinical examinations. In lesions that present in childhood, monitoring until skeletal maturity may allow for ultimately less radical treatment and less overall morbidity.  Special attention to cranial nerve function during monitoring of these lesions should be exercised  Decreased nerve function may be an indication for surgical therapy.
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  2. Medical treatment Currently, no medical therapy exists for the permanent cure of fibrous dysplasia. 1. Biphosphonates. 2. Systemic steroids
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  3. Surgical Remodelling: Chen YR, Noordhoff MS: Treatment of craniomaxillofacial fibrous dysplasia: How early and how extensive? Plast Reconstr Surg 86:835, 1990
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  4. Surgical Treatment Indications:  Functional concern  Facial recontouring  Compression of the optic canal, recommended decompression Other indications for surgical therapy:  Cosmetic Deformity  Pain  Pathologic Fracture  Hearing Loss  Sinus Or Nasal Obstruction  Epistaxis  Malocclusion and Impeded mastication.
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  Osteitis Deformans( Paget Disease)  Rapid turnover remodeling of bone throughout the skeleton.  Disease of the elderly.  Although two Paget-like bone dysplasias that arise during childhood.
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  Etiology  Defectivefunction of the osteoprotegerin/TNFRSF11A or B/RANKL/RANK pathway, a molecular regulator of osteoclastogenesis.
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  Classic Paget Diseaseof Bone ( CPDB)  Late adult onset.  Characterized by rapid turnover of bone remodeling and osseous expansion with progressive skeleton deformities.  Tubular bones show bowing and spinal curvature with vertebral collapse.  Elevated serum alkaline phosphatase,  Normal calcium and phosphorus levels.  Cranial nerve neuropathies can develop as a consequence of foramina narrowing.  Deafness
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  Radiographic Features In early stages, radiolucent “ Coin shaped” lesions appear in the flat bones of the skull, a condition called as “ Osteitis Circumscripta”
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   “Ground glass”trabecular pattern in the early stage.  “ Cotton wool” appearance in late lesions  Generalized hypercementosis
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  Histological Features Lesion shows marked evidence of bone turnover.  Resting and reversal lines of lamellar compact and trabecular bone are prevalent and haphazardly arranged into a mosaic pattern.
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  Neoplastic Transformation Two neoplastic processes may occur 1. Giant cell tumors 2. Sarcomas( Osteogenic sarcoma, fibrosarcoma, chondrosarcoma and undifferentiated sarcoma)
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  Treatment  Biphosphonates  Histological appearance also appear more normal after drug therapy.
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  Juvenile Paget Disease (Idiopathic Hyperphosphatasia)  Inherited as an autosomal recessive trait  Deformities in the long bones, kyphosis, acetabular protrusion and pathophysiologically by rapid turnover.  Long bone widening with pathologic fracture and thickening of skull.  Elevated serum alkaline phosphatase  Osteopenia and skeletal deformity with bowed limbs
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  Familial Expansile Osteolysis( FEO)  Autosomal dominant trait  Manifest in the second decade  Osteoclastic resorption with cancellous bone expansion and elevated serum alkaline phosphatase.  Early tooth loss by external resorption  Deafness  Histologically - focal collection of multinucleated giant cells and viral-like inclusions.
• 36.
  Expansile Skeletal Hyperphosphatasia(ESH)  Autosomal dominant trait  Accelerated bone turnover with hyperostotic expansion of the long bones  Pain in phalanges  Premature tooth exfoliation and deafness  Episodic hypercalcemia  Absence of large osteolytic lesions with cortical thinning.  Elevated alkaline phosphatase.  No viral like inclusions.
• 37.
  Segmental Odontomaxillary Dysplasia  Lesion confined to a single segment of the maxilla, usually in premolar and molar.  Clinical Features: ◦ Teeth fail to erupt ◦ Dental anomalies like- malformed, mis shapened and/ or teeth of anomalous size.  Expansion of alveolar bone
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  Radiographic Features Falling Sheet pattern
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  Histological Features Minimal osteoblastic rimming and the fibrous element is represented by small immature collagen with mild increase in cellularity.
• 40.
  Cemento-Osseus Dysplasia These conditions are defined by specific clinical and pathological features and have been classified as Cemento-Osseus Dysplasia  Periapical Cemental Dysplasia  Focal Cemento-Osseus Dysplasia  Florid Osseous Dysplasia
• 41.
   Precise etiologyis unknown.  Disorders of metabolism of cells normally involved in production of bone and cementum matrices.  The aberrant activity of the tissues may be the result of an unusual response to undefined local factors.
• 42.
  Periapical Cemental Dysplasia  Seen at the apices of the teeth with vital , non-inflamed pulps.  Predominantly involves mandibular incisors.  Usually detected incidentally on routine radiographic examination. Radiographic Examination  Consist of multiple round to ovoid , radiolucent lesions at the apex of the vital teeth.  May mimic periapical pathology of pulpal origin.  Individual lesions are seldom more than 1.0 cm in diameter and most are less than 0.5 cm in size.  The radiolucences maybe discrete with well defined borders or they maybe large enough to appear confluent as they overlap and merge.
• 43.
  Histopathology  OnBiopsy, they consist of multiple fragments of moderately cellular, collagenous tissue.  Amount and degree of mineralization component are variable, dependent on the length of time the lesions present and therefore the stage of the process.  The calcified tissue is associated with osteoblasts and the cementoblasts along the surface and is deposited in a variety of configurations.  Inflammatory cells are present
• 44.
  Focal Cemento-Osseus Dysplasia Clinical Features :  Female predominance.  4th -5th decades of life.  Solitary lesions , in posterior mandible.
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  Radiographic Features Diagnosed in routine radiographs, characteristically, asymptomatic.  Most lesions appear as radiolucent – radio-opaque areas.  In edentulous areas development of idiopathic bone cavities, result in bony expansion of affected area.
• 46.
  Histopathology  Consistencyof tissue removed for biopsies is important .  Difficult to curette form the sockets, is removed as multiple fragments of gritty tissues  Distinction between ossifying fibroma, which typically can be removed as large fragmented that can be separated cavity form bone. “Ginger root” Pattern
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  Treatment  Lesionsexhibit only limited potential for progressive growth, more lesion require no additional treatment following biopsy.  Periodic observation
• 48.
  Florid Cemento-Osseous Dysplasia  Middle-aged females  Painless non-expansile lesion often involving two or more jaw quadrants.  Radiographically - multiple confluent lobular radiopaque masses in tooth-bearing areas  Tendency toward bilateral, symmetrical involvement  Asymptomatic and detected incidentally
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   Jaw expansion- large lesions.  Dull pain or drainage are always associated with exposure of the sclerotic calcified masses to the oral cavity as the result of progressive alveolar atrophy under a denture or after extraction of teeth in the involved area.
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  Treatment  Oftendifficult, not very satisfactory.  In the asymptomatic patient observation  Antibiotics  Sequestration of the cementum-like masses will occur slowly and followed by healing.  Saucerization or surgical excision
• 52.
  Inflammatory/ Reactive Processes  This include: ◦ Focal Sclerosing Osteomyelitis( Condensing Osteitis) ◦ Diffuse Sclerosing Osteomyelitis ◦ Proliferative Periostitis
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  Focal Sclerosing Osteomyelitis ( Condensing Osteitis)  Mildest and most self-limiting form  Posterior mandible at apices of molar teeth  Bacterial origin  Pathogenic bacteria are of low virulence
• 54.
  Clinical Features Asymptomatic, nonexpansile periapical lesion  Early stages, radiolucency is seen at the apex, simulating a dental abscess, granuloma or cyst.  With time periapical radiolucency opacifies.  On histopathology no inflammatory cells are seen.  Treatment – Root canal therapy
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  Differential Diagnosis Focal osteosclerosis  Focal cemento osseous dysplasia
• 56.
  Diffuse Sclerosing Osteomyelitis  Unilateral diffuse ground glass opacification without defined boundaries of the mandibular body.  Cortical expansion  H/O dull episodic pain that last for weeks to subside and later become symptomatic again.  Caused by gram negative anaerobic bacteria of low virulence.  Definitive anaerobic culture  Source of infection - Odontogenic
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   Microscopically, boneexhibits a fibro osseous pattern with intervening foci of dense sclerotic bone.  Osseous elements are trabecular  Cementifying areas - absent.
• 59.
  Differential diagnosis LesionClinical Features Histological Features Fibrous Dysplasia Painless lesion Chinese figure pattern Florid cememto osseous dysplasia Multiquadrant opaque lesions with associated radiolucencies Show both trabecular and cementifying areas along with hollow bone cavities
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  Proliferative Periostitis Low grade infections progress of DSO involves periosteoum.  Induces neo-osteogenesis and periosteal layer becomes redundant, yielding classic “onion skinning” phenomenon.  Histologically, periosteum discloses a trabecular pattern that is often reteform with a tendency for parallel orientation
• 61.
  Treatment  Removingodontogenic infection source by extraction or RCT.  Long term antibiotic therapy.
• 62.
  Hyperparathyroidism  The“brown tumor” of hyperparathyroidism, a giant cell lesion, may be encountered anywhere in the skeleton in both primary and secondary HPT.  Reported among patients with renal osteodystrophy.
• 63.
  Clinical Features Marked facial deformity  Thickening of dipole and massive maxillomandibular enlargement with protrusion of anterior teeth and wide diastemas.  Also known as – Sagliker Syndrome and the Uglifying Human Face Syndrome.  Histologically, trabecular pattern is seen
• 64.
   Enlarged regionsof facial bones, jaws and skull manifest a dense ground glass opacification.  Parathyroidectomy does not result in resolution of the bony enlargements.
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  Ossifying Fibromas Neoplasms with a fibro-osseous histology represented by the ossifying fibroma group of lesions.  Neoplasms in the true sense exhibiting progressive proliferative capabilities with bony expansion and well defined margins radiologically.
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  Types  Ossifying/Cementifying Fibroma  Juvenile Ossifying Fibroma  Trabecular Juvenile Ossifying Fibroma  Psammomatoid Juvenile Ossifying Fibroma  Gigantiform Cementoma
• 67.
  Ossifying/Cementifying Fibroma Most common form of OF occurs in maxilla and mandible.  Mutation in HRPT2 gene that encodes parafibromin protein.  Painless with expansion of both cortices.  Larger lesions may expand the inferior aspect of mandible.  Teeth are displaced superiorly ( mandibular lesion) and inferiorly( maxillary lesion) and expand into the antrum.
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  Radiographic Features Early lesions appears radiolucent  With time it appears radiopaque, as more matrix calcifies.
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  Histological Features Shows three histological forms ◦ Ossifying ◦ Cementifying ◦ Storiform
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  Juvenile Ossifying Fibroma  Also known as Juvenile Active Ossifying Fibroma and Juvenile Aggressive Ossifying Fibroma.  2 clinicopathologic entities 1. Trabecular Juvenile Ossifying Fibroma ( TrJOF) 2. Psammomatoid Juvenile Ossifying Fibroma (PsJOF)
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  Trabecular Juvenile Ossifying Fibroma(TrJOF)  Also known as trabecular desmo-osteoblastoma.  Majority of patients are children and adolescents.  Only 20% are over 15 years of age.  M:F = 1:1  Maxilla and mandible are dominant sites.  Maxilla is slightly more affected.
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  Clinical Features Progressive and sometimes rapid expansion of bone  In maxilla, obstruction of nasal passages and epistaxis may be present.
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  Radiographic Features Expansive and well demarcated  With cortical thinning and perforation  Shows varying amount of radiolucency and opacity depending upon amount of calcified tissue.  Ground glass and honeycomb appearance.
• 74.
  Histological Features Uncapsulated and shows infiltration of surrounding bone  Characteristic loose structure  Stroma is cell rich, with spindle or polyhedral cells, produce little collagen  Cellular, immature osteoid forms strands.  Irregular mineralization takes place at the centre of the strands  Local aggregates of osetoclastic giant cells are invariably present in the stroma.
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   Clinical courseis characterized by infrequent recurrence following conservative excision.  Complete cure could be achieved in those cases without resorting to radical surgical intervention.  Malignant transformation not reported
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  Psammomatoid Juvenile OssifyingFibroma  Affects extragnathic craniofacial bones, particularly periorbital, frontal and ethmoid bones.  Gogl,1949, as psammomatoid fibroma of the nose and paranasal sinuses.  Margo,1985 described as a distinctive solitary fibro-osseous lesion that affects the orbit and shows distinctive histologic features.
• 77.
   16 to33 years.  Range of 3 months to 72 years.  Majority originates in paranasal sinuses ( frontal and ethmoid).  10 % in calvarium  7% in mandible( Makek in 1983)
• 78.
  Clinical Features Bone expansion involves orbital or nasal bones and sinuses.  Orbital extension- proptosis and visual complaints including blindness, nasal obstruction, ptosis, papilledema and disturbances in ocular mobility.
• 79.
  Radiographic Features Round, well defined, corticated osteolytic lesion with a cystic appearance.  In CT scans, appear less dense than normal bone, appear multiloculated  Size range from 2 to 8 cm  In facial skeleton a well circumscribed expansive mass with a thick wall of bone density on CT scan is strongly suggestive of psammomatoid juvenile
• 80.
  HISTOPATHOLOGY  Ongross examination tumor is yellowish, white and gritty.  Histologically, multiple round uniform small ossicles (psammomatoid bodies) embedded in a cellular stroma composed of uniform, stellate, and spindle shaped cells.  Psammomatoid bodies are basophilic and bear superficial resemblance to dental cementum, but may have an osteoid rim.
• 81.
   Surgical excisionis treatment of choice.  Recurrence rate of >30% reported.  No malignant change observed.
• 82.
  Familial Gigantiform Cementoma  An autosomal dominant variant usually involving multiple quadrants with variably expansile lesions.  Anterior mandible.  No racial predilection.  Often evolve during childhood and can grow rapidly.
• 83.
   Radiographically, expansionwith a radiolucent mass containing floccular calcifications.  Microscopically, benign hypercellular stroma with monomorphic appearing fibroblasts and mature collagen fibers.  Ovoid, laminated, psammomatoid calcifications are
• 84.
   Treatment isresection with immediate or staged reconstruction.