Benign Neoplasia of Bone Flashcards
Benign bone forming tumors produce ___ or ___
unmineralized osteoid or mineralized woven bone
An osteoma enostoma is ___-growing and comprised of ___ bone
slow-growing and comprised of dense cortical bone
What are the clinical subtypes of osteoma/enostoma by location?
Osteoma:
1. Calvarial and mandibular
2. Sinonasal and orbital bone
Enostoma (hamartoma):
1. Medullary bone “islands”
2. Long bone surfaces
What is Gardner syndrome?
How does it relate to bone tumors?
Inherited condition causing multiple polyps in colon and possibly multiple osteomas
Are osteomas usually solitary or multiple?
Solitary
In what case would an osteoma be removed?
Surgical removal if in sensitive location
Enostomas can mimic ___
blastic metastasis
What is the clinical significance of osteoma/enostoma?
Usually minimal
What is the distribution of osteoid osteoma among sexes?
Male > Female (3:1)
What age group is most affected by osteoid osteoma?
5-35 years of age
Where in the bone does osteoid osteoma typically arise?
In cortex, but may arise in medullary cavity
What is the size of osteoid osteoma?
< 1 cm in diameter
How does osteoid osteoma present radiographically?
Radiolucent lesion surrounded by sclerotic bone
What does nidus refer to?
Osteoid osteoma
osteoid osteoma
What does nidus contain?
Irregular trabeculae of woven bone within a vascular fibrous stroma containing osteoblasts and osteoclasts
How do trabeculae in the center of a nidus compare to those in the peripheral?
Center trabeculae are more mature and may be ossified
With osteoid osteoma/nidus, there are ___ levels of Prostaglandin E2
high levels
PGE2 is produced by ___ increasingly with osteoid osteoma
proliferating osteoblasts
osteoid osteoma
PGE2 is up to 12 times ___ in nidus than outside
greater
What are some reasons pain is worse at night with osteoid osteoma?
- PGE2 produced by proliferating osteoblasts increases
- PGE2 is up to 12x greater in nidus than outside
- Vasodilation of vascular components in the stroma
Osteoid osteoma pain is relieved by ___ because of ___
aspirin/NSAIDs because of vasoconstriction mechanism
Osteoblastoma is similar histologically to ___
osteoid osteoma
In which bones does osteoblastoma generally occur?
Axial skeleton: laminae and pedicles
What is the size of an osteoblastoma?
> 2 cm diameter with progressive enlargement
How does an osteoblastoma appear radiographically?
Radiolucent lesion without sclerotic reaction
Is osteoblastoma painful?
Painful, but less so than an osteoid osteoma
Is osteoblastoma pain responsive to aspirin?
No
Osteoid osteoma and osteoblastoma are often treated similarly:
- Surgical excision via curette
- Radiofrequency ablation
What may be required when surgically excising osteoblastoma via curette?
Wide bloc resection
What is radiofrequency ablation?
An electric probe is inserted into the tumor
What is the name for a benign cartilage forming tumor within bone?
Osteochondroma
An osteochondroma is also called an ___
exostosis
What is the most common benign skeletal tumor?
Osteochondroma
How is osteochondroma distributed among sexes?
Male > Female (3:1)
When is osteochondroma usually diagnosed in life?
Skeletal immaturity
What are the two types of osteochondromas?
- Pedunculated
- Sessile
__% of osteochondromas are solitary
85%
__% of osteochondroma are hereditary multiple exostosis
15%
What is osteochondromatosis?
Hereditary multiple exostosis: autosomal dominant hereditary disease
Up to __% of those with hereditary multiple exostosis may undergo malignant degeneration
25%
With osteochondroma, there is loss of function mutations in ___ which may disrupt local cartilage growth and chondrocyte differentiation
tumor suppressor genes EXT1 or EXT2
If a patient is found to have loss of function mutations in tumor suppressor genes EXT1 or EXT2, what may be the result?
Osteochondroma
How does pedunculated osteochondroma appear?
Bony stalk capped by cartilage
How does sessile osteochondroma appear?
Don’t often have a cap, cartilage is intermingled
Osteochondroma only affects ___ bones
endochondral
Osteochondroma arises from where in bone?
Metaphysis near growth plate
Osteochondroma usually stops growing with ___
epiphyseal fusion
What are common sites for osteochondroma?
Knee is common site
Also, pelvis, scapula, ribs
The cartilaginous cap of osteosarcoma is covered by ___
perichondrium
The cartilaginous cap of osteosarcoma merges into ___ below where chondrocytes arrange according to the growth plate
spongiosa
How many osteochondromas are considered solitary?
< 6
Are osteochondromas usually solitary or multiple?
Solitary
Is osteochondroma generally painful or painless?
Generally form painless, potentially palpable lumps
In which type of osteochondroma does pathological fracture occur?
Pedunculated
What are some reasons osteochondroma might be painful?
- Pathological fracture (pedunculated only)
- Tendinosis/bursitis
- Neurovascular bundle impingement
- Malignant transformation (<1% for solitary)
How are bones shaped when hereditary multiple exostosis is present?
Affected bones may be bowed and shortened
Multiple bones with osteochondromas (6-100s)
Benign cartilaginous tumors form which type of cartilage?
Hyaline cartilage
Benign cartilaginous tumors mostly form when in life?
Prior to 20 years of age
Benign cartilaginous tumors form in ___ bones
endochondral
What are the two subtypes of benign cartilaginous tumors?
- Enchondroma
- Juxtacortical chondroma
benign cartilaginous tumors
Enchondroma arises in the ___
medullary cavity
benign cartilaginous tumors
Juxtacortical chondroma arises on the ___
surface of bone
What is the etiology of benign cartilaginous tumors?
Mutations in genes related to chondrocyte development
If a benign cartilaginous tumor arises in the medullary cavity, what type is it?
Enchondroma
If a benign cartilaginous tumor arises on the surface of bone, what type is it?
Juxtacortical chondroma
Is enchondroma solitary or multiple?
Solitary lesion
___% of enchondromas undergo malignant transformation
<1%
What is Ollier disease?
Multiple enchondromas (benign cartilaginous tumors), possible hereditary component
___% of enchondromas related to Ollier disease undergo malignant transformation
25%
What is Mafucci syndrome?
Rare
Multiple enchondromas (benign cartilaginous tumors) and soft tissue hemangiomas
___% of enchondromas related to Mafucci syndrome undergo malignant transformation
50%
How common is periosteal/juxtacortical chondroma?
Rare
What is the most common benign tumor of hands and feet?
Benign cartilaginous tumor (enchondroma)
What are some symptoms of a benign cartilaginous tumor?
- Usually asymptomatic, but occasionally painful
- Pathological fractures
If a patient has the following radiographic findings, what is suspected?
- Geographic lytic lesion with or without a sclerotic border
- May or may not have matrix calcification
- Intact and thinned cortex with endosteal scalloping
- Deformities
Benign cartilaginous tumor
What are the radiographic findings for a benign cartilaginous tumor?
- Geographic lytic lesion with or without a sclerotic border
- 50% have matrix calcification
- Intact and thinned cortex, endosteal scalloping
- Deformities
What are the treatments for asymptomatic benign cartilaginous tumors?
None, maybe monitor
What is the treatment for disruptive osteochondromas or juxtacortical chondromas?
Surgical removal
What is the treatment for problematic enchondromas?
Curettage
How are complications of benign cartilage tumors treated?
- Surgical removal (disruptive osteochondromas or juxtacortical chondromas)
- Curettage (problematic enchondromas)
- Treatment for pathological fracture
- Monitor for and treat malignant degeneration
Chondroblastoma occurs most commonly in ___ of ___ bones
epiphyses and apophyses of endochondral bones
What is the distribution of chondroblastoma among sexes?
Males > Females (2:1)
What age group is typically affected by chondroblastoma?
Ages 5-25
What are the radiographic features of chondroblastoma?
- Slow growing
- Geographic lytic
- Well-defined borders
What are symptoms of chondroblastoma?
Presents with joint pain
Giant cell tumor of a bone is also known as ___
osteoclastoma (benign tumor of unknown origin)
Giant cell tumors typically occur in what age group?
Ages 20-40
How are giant cell tumors distributed among sexes?
Female > Male (3:2)
___% of giant cell tumors are benign
___% are malignant
> 80% are benign
<20% are malignant
Giant cell tumors consist of ___ cells with proliferating ___ cells
osteoclastic multinucleated giant cells with proliferating mononuclear cells
What gives giant cell tumors the gross appearance of a sponge filled with blood?
Multiple hemorrhagic areas
Neoplastic cells found in a giant cell tumors express high levels of ___
RANKL
giant cell tumor
What is the function of RANKL?
- Promotes osteoclast precursor proliferation
- Affects expression of RANK which leads to differentiation of mature osteoclasts
How is the bone matrix affected by giant cell tumors?
Localized, highly destructive resorption of bone matrix
Are giant cell tumors solitary or multicentric/multilocular?
Usually solitary lesions, but may be multicentric or multilocular
Giant cell tumors arise in the ___ and extend into ___
What is this called?
arise in the metaphysis and extend into epiphysis
This is called subarticular extension
Where do 50% of giant cell tumors of bone occur?
50% of cases occur around the knee (distal femur and proximal tibia)
Besides the knee, where might you find a giant cell tumor?
Distal radius, humerus, and fibula
How often do giant cell tumors of bone become malignant and metastasize to the lungs?
How often are they fatal?
Rarely metastasize to the lungs
Rarely fatal
(Often spontaneously regress)
What are the clinical manifestations of giant cell tumors of bone?
- Non-specific regional pain
- Pathologic fractures
- Joint pain and decreased range of motion
- Possible functional disability
What are radiographic characteristics of giant cell tumors of bone?
- Geographic lytic lesion
- If expansile, bone surrounding lesion is often very thin
- Frequently multiloculated appearance
Why do giant cell tumors of bone frequently have a multiloculated appearance?
Endosteal bone resorption
What are treatments for giant cell tumors of bone?
- Curettage (40-60% recur locally)
- Denosumab (RANKL inhibitor)
