Fibro-osseous Lesions Flashcards
A diverse group of processes that are characterized by replacement of normal bone by fibrous tissue containing a newly formed mineralized product
Fibro-osseous lesions
Fibro-osseous lesions of the jaw: entities most commonly include
Ossifying fibroma
Fibrous dysplasia
Cemento osseous dysplasia
Periapical/focal
Florid
Chronic osteomyelitis
Composed of a fibrous connective tissue stroma in which new bone is formed, it is classified as one of the benign fibrous-osseous lesions of the jaw
Ossifying fibroma
Uncommon lesion that tends to occur during the 3rd and 4th decades of life.
Women > men
Ossifying fibroma
Generally a slow growing, asymptomatic and expansile lesion.
May be seen in jaws, anterior cranial fossa, craniofacial bones
Ossifying fibroma
An ossifying fibroma that occus in younger pstient (children)
Juvenile ossifying fibroma
Important radiographic features of ossifying fibroma
Well-circumscribed
Sharply defined borders
Generally expansile profile
Well-circumscribed radiolucency or mixed radiolucency
Two variants of ossifying fibroma that occur in younger patient
Juvenile trabecular ossifying fibroma (JTOF)
Juvenila psammomatoid ossifying fibroma (JPOF)
Ossifying fibroma variant that is characterized by progressive and sometimes rapid growth but rarely painful.
Juvenile trabecular ossifying fibroma
A variant of OF that radiographically, shows a defined border and can range from radiodense to radiolucent.
Juvenile trabecular ossifying fibroma
A variant if OF that microscopically, has a high cellular and contains trabeculae or spheroids of new bone
Juvenile trabecular ossifying fibroma
Extragnathic craniofacial bone location of juvenile psammomatoid ossifying fibroma
Paranasal sinuses
Periorbital bones
Where it can cause exophthalmos, proptosis, sinusitis and nasal symptoms
Juvenile psammomatoid ossifying fibroma occurs principally in ___ craniofacial bones
Extragnathic cranofacial bones
A variant form of OF that microscopically, is formed by cellular stroma containing small, rounded calcifications.
Juvenile psammomatoid ossifying fibroma
Treatment for ossifying fibroma
Surgical excision or curretage
Resection if shows an aggressive behavior
Dd of ossifying fibroma
Fibrous dysplasia
Osteoblastoma
- younger age, pain
- osteoblasts (++)
- central nidus
Periapical cemento osseous dysplasia
- (+) posterior teeth
- needs biospy confirmation
Focal osteomyelitis
- inflammation and pain
Ossifying fibroma is clinically, microscopically identical to ?
Cementifying fibroma aka cemento ossifying fibroma
Composed of fibrous connective tissue with well-differentiated, spindled fibroblasts.
Ossifying fibroma
Bone is immature and often surrounded by osteoblasts.
Osteoclasts are infrequently seen
Ossifying fibroma
Why does ossifying fibroma and fibrous dysplasia a primary diagnostic challenge in distinguishing them both?
They may exhibit similar clinical, radiographic and microscopic features.
The most helpful feature in distinguishing fibrous dysplasia and ossifying fibrous is?
OF is well-circumscribed. Well-defined appearance is evident.
And the ease with which it can be separated from normal bone
What gene does fibrous dysplasia have but ossifying fibroma doesn’t have?
GNAS 1a gene
Most commonly presents as an asymptomatic, slow enlargement of single/several bone
Fibrous dysplasia
Fibrous dysplasia that is used to describe the process in one bone
Monostotic fibrous dysplasia
Fibrous dysplasia that applies to cases in which more than one bone is involved.
Polyostotic fibrous dysplasia
Which is more common. Polyostotic or monostotic fibrous dysplasia?
Monostotic fibrous dysplasia (80%) of cases
When fibrous dysplasia maxillary lesion that may extend to involve the maxillary sinus, zygoma, sphenoid bone and floor of the orbit. This is now referred to as?
Craniofacial fibrous dysplasia
Maxilla > mandible for fibrous dysplasia. But, if lesion is in mandible, the most common occurrence is where?
Body of the mandible
Onset of fibrous dysplasia
First or second decade of life
Gender predisposition of mono and poly fibrous dysplasia
Monostotic = gender prediection
Polystotic = more common in female
Radiographic appearance of fibrous dysplasia
Radiopaque that imparts a “ground glass” or “peau d’orange” effect
How many radiographic patterns is fibrous dysplasia have?
Radiolucent to radiopaque mass
1. Ground glass effect
2. Unilocular or multilocular radiolucency - in long bones
3. Mottled radiolucent and radiopaque appearance - long standing disease
Aside ffrom ground glass effect seen in radiographic features of fibrous dysplasia. What are the other radiograph features to support that the lesion is a fibrous dysplasia?
Fingerprint bone pattern
Superior displacement of the mandibular canal in mandibular lesions
An important distinguishing feature of fibrous dysplasia
Poorly defined radiographic and clinical margins of the lesion
Normal medullary bone is replaced by an abnormal fibrous connective tissue proliferation in which new, nonmaturing bone is formed
Fibrous dysplasia
Lab findings in fibrous dysplasia for monostotic and polyostotic
Mono = Serum calcium, phosporus, alkaline phosphatase are normal
Polyostotic (McCune-Albright syndrome) = altered
DD of fibrous dysplasia
Ossifying fibroma
Chronic osteomyelitis
- inflammation, tenderness, pain
Malignancy (osteosarcoma)
Treatment for fibrous dysplasia
Though growth, it stabilizes
Surgical recontouring for large lesions that causes functional deformity
RANKL medications - to improve pain and bone density
A type of fibrous dysplasia that can cause malignant transformation, though less than 1% of cases
Polyostotic type of fibrous dysplasia
% of regrowth in fibrous dysplasia
25%
Unusual response of Periapical bone and cementum to some undetermined local afactori
Periapical cemento-osseous dysplasia
3 types of cemento osseous dysplasia
Periapical COD
Focal COD
Florid COD
Characterized by the replacement of normal bone with a collagenous matrix containing trabecular of immature bone and in some instances, cementum-like material
Cemento osseous dysplasia
Uncommon primary lesion of bone that arises in maxilla or mandible
It is a benign neoplasmof undetermined cause
Osteoblastoma
A lesions that Clinically and histologically, they may be confused with osteosarcoma
Osteoblastoma
CM in diameter for osteoblastoma and steoid osteoma
Osteoblastoma = larger than 1.5cm in diameter
Osteoid osteoma = 1.5cm or less
Common location of osteoblastoma
Most often in vertebrae and long bones
Less in jaws
Common location of osteoblastoma if located in the jaw
Posterior tooth bearing regions of maxilla and mandible
Age for osteoblastoma
Second decade
90% appears before age of 30
Gender predilection of osteoblastoma
2:1
Male , female
Radiographic feature of osteoblastoma
Well circumscribed and have a lytic to mixed lucent-opaque pattern
A constant feature of osteoid osteoma that may be absent in osteoblastoma
Sclerosis of perilesional bone
Composed of irregular trabecular of osteoid and immature bone within a stroma containing a prominent vascular network
Osteoblastoma
DD of osteoblastoma
Cementoblastoma
Ossifying fibroma
Fibrous dysplasia
Osteosarcoma
Treatment for osteoblastoma
Conservative surgical approach (curettage or local excision)
Associated with gardner’s syndrome
Consists of mature, compact, or cancellous bone.
Osteoma
Osteoma that arise on the surface are called ___
Osteoma that develop centraly within bone ___
Periosteal osteoma
Endosteal or solitary central osteoma
Age and gender predilection of osteoma
2nd to 5th decade of life
Male > female
An osteoma that clinically presents as asymptomatic, slow-growing, bony, hard masses.
Periosteal osteoma
An osteoma that occurs within the medullary bone and may be discovered during routine radiographic exam as dense, well-circumscribed radiopacities
Endosteal osteomas
70% of cases located within the mandible
Osteoma
Symtpoms associated with these tumor .
Headaches, recurrent sinusitis, ophthalmologic complains
Osteomas
Inherited as an autosomal-dominant disorder, is characterized by intestinal polyposis, multiple osteomas, fibromas of the skin, epidermal and trichilemmal cysts, impacted permanet and supernumerary teeth and odontomas
Gardner syndrome
Genetic defect is gardner syndrome is found in?
Small region on the long arm of chromosome 5 (5q21)
Where the familial adenomatous polyposis (APC) gene resides
Intestinal polyps associated with gardner syndrome are commonly located in the __ and __
Colon and rectum
Two distinct histologic variant of osteoma
- Composed of relatively dense, compact bone with SPARSE marrow tissue.
- Lamellar trabecular of cancellous bone with ABUNDANT fibrosis-fatty marrow
Osteoblasts may be numerous, but osteoclasts are sparse
Osteoma
DD of osteoma
Exostosis
Osteoblastoma/osteoid osteoma
Odontoma, cemenoblastoma, condensing osteitis, focal sclerosing osteomyelitis
Developmental
- Single/multiple bone
- Max > mndi
- Slow, painless swelling
- Polyostotic; syndromes (mccune albright syndrome)
Fibrous dysplasia
Most common: tooth bearing areas
- Mid-aged female, asymptomatic
Cemento osseous dysplasia
Neoplasm
- 20-30 years old: female
- Mandi < max
- Small: asymptomatic
- Large: painless swelling
Ossifying fibroma
Mode of ossification of bone
Intramembranous ossification
Darker purple stain indicates?
Immature bone or woven bone
In this lesion, the bone is predominantly woven
Bony trabeculae assume irregular shapes likened to chinese characters
Fibrous dysplasia
Composed mostly of lamellar bone, compact or trabecular, in which osteoblasts and osteoclasts are usually inconspicuous
Osteoma
