Bone Tumors Flashcards
Osteoma
A tumor-like mass of abnormally dense bone (usually polypoid)
- almost exclusively in the skull (paranasal sinuses and facial bones)
- 40-50s
Gardner’s syndrome (osteomas, epidermal cysts, fibromatosis and colonic adenomatous polyposis)
Osteoid Osteoma
Epidemiology
Xray
A benign, highly vascular, sharply circumscribed osteoblastic proliferation less than 1.5 cm
- single
- intracortical in long bones
Epidemiology:
10-40
M:F 2:1
12y/o with bone pain worse at night relieved by aspirin
X-ray:
Targetoid appearance on X-ray due to pattern of ossification. CT and MRI are far more sensitive
Detectable by bone scan
-Intracortical osteoid osteoma
Histology:
Haphazard bone and osteoid
Rimmed by osteoblasts
Stroma-loose connective tissue, vascular
Conventional Osteosarcoma
Osteoblastic Osteosarcoma
High grade sarcoma producing immature osteoid
- painful tender mass
- Often large, metaphyseal centered, fleshy or hard tumor, which can contain cartilage
60% knee, 15% hip, 10% humerus, 8% face
peak age 10-20
Etiology unknown
Histology:
-anaplastic malignant tumor cells
High Grade
Imaging:
lytic blastic lesion with cortical destruction
-sunburst pattern
-periosteal elevation (codman’s triangle)
Gross:
metaphysically centered
-fleshy or hard tumor
What is a codman triangle?
Osteoblastic OSTEOSARCOMA
triangular shadow between cortex and raised ends of periosteum
(tumor has broken through the cortex and lifted the periosteum resulting in reactive periosteal bone formation)
Parosteal Osteosarcoma
Low Grade
Imagining: heavily mineralized mass attached to the cortex with a broad base
-posterior distal femur
Histology:
well formed bony trabeculae in hypocellular stroma
-stromal spindle cells with minimal atypia
-50% cartilaginous differentiation
Periosteal Osteosarcoma
Intermediate Grade
Imaging: arising on the surface of the cortex
-displays non homogenous calcified spiculations that are deposited perpendicular to the cortex and overall sunburst appearance
Histopathology:
moderately differentiated chondroblastic osteosarcoma
Osteochondroma
An outgrowth of medullary and cortical bone, covered by cartilaginous cap, which projects from the cortical surface of the involved bone
Considered to be a malformation (exostosis) and not a true neoplasm
24% distal femur, 16 humerus, 15% knee
20 year olds
Histology:
fibrous band
cartilage cap
endochondral ossification
Osteochonromatosis
Multiple hereditary exostoses
Severe bone deformities with shortening and broadening of tubular bones
Usually manifests by adolescence and ceases in adulthood
autosomal dominant
Chondrosarcoma
Malignant cartilage forming tumor
>40 yrs men>women
-painful enlarging masses
-metabolize to lungs, skeleton
-prognosis related to grade, size (5 year 90% grade 1, 43% grade 3)
hip 27%, proximal humerus 19%, 10% ribs, 10% humerus
Histology:
Bone permeation
Bone entrapment
Treat:
surgery
some variants chemotherapy
Grade 1 chondrosarcoma
Mildly cellular Little pleomorphism myxoid and necrotic areas are sparse or absent no mitotic activity metastases are uncommon
Grade 2 chondrosarcoma
Moderate cellularity Frequent myxoid stroma mild to moderate necrosis occasional mitotic figures 10-33% rate of metastases
Grade 3 Chondrosarcoma
High cellularity High pleomorphism Extensively myxoid Frequent necrosis Mitosis are readily identifiable 70% rate of metastases even with adequate local control
Ewing’s sarcoma
a primary osseous neoplasm of small, round, and relatively uniform mesenchymal cells with no microscopic evidence of matrix production
characteristically rich in cytoplasmic glycogen
90% t(11;22)(q24;q12)*** chromosomal translocation
—Fusion EWS/FLI-1 —overexpression of FLI-1
25% femur
peak 20 y/o
X-ray:
onion skin appearance
-sarcoma invading cortex and adjacent soft tissue
Histology:
- proliferation of small round cell tumor cells
- homer wright rosettes
Fibrous dysplasia
a benign intramedullary proliferation of fibrous tissue and bone
osseous component is irregular distributed distributed and is composed of woven bone with NO osteoblastic rimming
most cases single bone but polyostotic in 20%
one of the most common benign fibrous proliferations
22% femur
peak age 15
Radiographically:
well demarcated
expansile lesions
ground glass appearance
conspicuous calcification may be present
erosion through the cortex may occur
prominent periosteal reactivation when fractured
Histology:
curvilinear bone trabeculae
McCune Albright’s syndrome
- polyostotic fibrous dysplasia (multifocal)
- precocious puberty
- usually unilateral macular pigmented skin lesions (cafe-au-lait spots)
- fibromyxomatous soft tissue tumor
- recurrent fractures may lead to deformities of the lower extremities
Genetics:
- mutation of GNAS 1 gene that encodes the alpha subunit of the stimulatory G protein coupled receptor GsAlpha
- albright hereditary osteodystrophy
- Activating mutations occur post-zygotically replacing the arginine residue amino acid with either a cysteine or histidine
- cells that derive from mutated cells manifest the dysplastic features
