Bone Tumors Flashcards
How are bone tumors usually classified ?
By the Normal cell or matrix they produce
- if a lesion they are grouped by clinicopathologic features.
Osteoid osteomalacia and osteoblastoma
Bending bone producing tumors that are similar histologically but located differently
- both appear round/oval masses of tan tissue w/ dilated and congested capillaries surrounding
- both usually dont involve malignancies
Osteoid osteoma: metaphysis of long bones
Osteoblastoma: Vertebral column
Specifics of osteoid osteoma
Less than 2 cm diameters and are more common in men than women (1.6:1)
- usually occur in femur or Tibia diaphysis
- always marked with severe nocturnal pain that can be relieved by aspirin or NSAIDs
- almost always elicit a reactive bone formation
- pain is expected to be caused by prostaglandin E2 produced by osteoblasts*
specifics of Osteoblastoma
Larger than 2 cms and is most frequently found in posterior components of vertebrae
- is marked by nocturnal pain that cannot be subdued via aspirin and NSAIDs
- Doesnot induce a marked bony reaction
Osteosarcoma specifics
Malignant tumor that produces osteoid matrix
Common primary malignant tumor of bone
Contains a bimodal age distribution
Bimodal age distribution of osteosarcoma
1 peak: 75% occur in persons younger than 20
2 peak: older adults with paget disease, bone infants or previous radiation
Most common sites of osteosarcoma
Distal femur and proximal tibia in the metaphyseal regions.
Metaphyseal regions are common due to increased proliferation seen in these regions.
Osteosarcoma pathogenesis
- 70% have acquired genetic abnormalities
Common mutated oncogenes (inactivated)
- RB (cell regulator)
- TP53 (initiation of apoptosis)
- CDKN2A (tumor suppressors)
Osteosarcoma morphology
Bulky gray-white tumors
Frequently show destructions of surrounding tissues and spread into the medullary canal, replacing the marrow.
- most prevalent marked sign is increased formation of osteoid matrix or mineralized bone
- usually painful and can cause sudden fractures of bones.
Osteosarcoma treatment
Neoadjuvant chemotherapy, surgery and additional chemotherapy.
- usually spread hematogenously to the lungs
- usually poor outcome
Osteochondromas “exostosis” characteristics
Begin cartilage tumor that attaches to underlying Skeleton by a bony stalk.
85% are solitary and the rest are developed by multiple hereditary exostoses syndrome
Males are 3x more likely to be affected than females
Commonly diagnosed in late adolescence and early adulthood
Multiple hereditary exostoses syndrome
Caused by germline loss of function in EXT1 or EXT2 genes
Encode enzymes that synthesize heparan sulfate glycosaminoglycans
Causes chondrocytes in growth plate to not differentiate properly.
Osteochondroma sites of development
Only develop in bones of endochondrial origin growth and usually arise from the metaphysis of long bones.
Osteochondroma morphology
Sessile: smooth tumor inline with bone
Pedunculated: raised tumor that “sprouts” out of bone
Both are comprised of a cap of begging hyaline cartilage and surrounded by perichondrium
Both have a stalk that are continuous with the medullary cavity of the bone.
Clinical features of osteochondromas
Slow growing masses that can be painful due to nerveimpingement or stalk fractures
Can be cured by simple excisions
Chondroma characteristics
Begin tumors of hyaline cartilage that only arise in bones of Endochondral origin.
- arise within medullary cavity
- usually diagnosed in people between 20-50 years of age
- typically arise in metaphyseal regions of tubular bones in hands and feet (phalanges)
- produce a C or O ring sign
Ollie’s disease and Maffucci syndrome
Diseases caused by multiple enchondromas that are very prevalent in radiographs
Chondroma morphology
Usually small gray-blue translucent nodules.
Outsides can appear calcified via spontaneous enchondral ossification
Chondroma clinical features
Most are symptomatic, with only occasional pain
- only diagnosed through observation or accidental detection
Chondrosarcoma characteristics
Malignant tumors that produce cartilage
- half as common as osteosarcomas
- usually men in their 40s or older
- sometimes arise secondary to osteochondromas
Almost always found in axial Skeleton bones
Chondrosarcoma morphology
Large bulky tumors composed glistening gray-whites cartilage
Appear spotty calcifications and tumor spreads into muscle and fat surrounding it.
Assigned grade 1-3 depending on how differentiated it is (3= less differentiated)
Clinical features of Chondrosarcoma
Very painful and grow quickly
Tumor grade predicts outcome
Grade 1: 80%
Grade 3: 43%
Grade 3 is usually the only one that metastasizes and does it hemarogenously, usually to the lungs.
Ewing sarcoma
Malignant tumor composed of primitive round cells with varying degree of differentiation
- 2nd most common bone sarcoma Behind osteosarcoma
- usually present in children <20 age
- white males experience slightly more frequency
Ewing Sarcoma Locations and pathogenesis
Arise in the diaphysis of long tubular bones.
Usually caused by a translocation that fuses the EWSR1 gene to the FLI1 gene
Ewing sarcoma morphology
tumors appear soft tan-white, arising in the medullary cavity
Can appear small, round and blue single cell tumors in children
Usually contains areas of hemorrhage and necrosis
Tumors DONT produce bone or cartilage
Homer-Wright rosettes
Round groupings of cells with central fibrillary core. Usually present in Ewing sarcomas
Ewing sarcoma clinical features
Painful enlarged masses
Site is usually warm, tender and swollen
Layers of reactive bone appear deposited in onion-layered like fashion.
Treated with neoadjuvant chemo and surgical excision
50% mortality without chemo
25% mortality w/ chemo
Giant cell tumor characteristics
Multinucleated osteoclast-type giant cell that dominate the histology slide they are presented in.
- almost exclusively affects adults
- usually occurs in epiphysis of long bones (specifically distal femur and proximal tibia)
Giant cell pathogenesis
Osteoblast precursors that express high levels of RANKL causing increased proliferation and differentiation into osteoclasts.
Giant-cell morphology
Red-brown masses that dominant the image and can sometimes appear to have a thin shell of reactive bone surrounding it.
Often destroy the overlying cortex of bone.
Microscopically appears to lack bone or cartilage and only contains mononuclear tumor cells.
Giant-cell clinical features
Usually found in joints so often appear with similar symptoms to arthritis (pain/inflammation in joints)
40-60 % recurrence rate in local tissues after treatment
Treatment include curettage and RANKL inhibitor Denosumab.
Aneurysmal Bone Cyst (ABC)
Benign tumor of bone that has multinucleate blood filled cystic spaces
Usually found in posterior elements of vertebrae and metaphysis of long bones (specifically proximal tibia and distal femur)
Affects males and females equally and occurs within 20 years of age.
ABC morphology
Consists of blood-filled cystic spaces separated by thin tan-white septae
Septae are composed of fibroblasts, multinucleated giant cells and reactive woven bone.
NOT covered by endothelium
ABC clinical features
Pain and swelling almost always appear
Appears as a metaphyseal lesion with all-defined margins on x-rays
May demonstrate internal septa and varying fluid levels on CT and MRIs
Treatment is surgical excision and curettage
Low risk of recurrence
Non-ossifying Fibroma
Benign likely reactive mesenchymal proliferative cell
often present in children/young adults between ages 2-25 (occurrence rate is roughly 50%)
Form cellular lesions containing fibroblasts and macrophages
Most arise from the metaphysis of distal femur and proximal tibia
Most undergo spontaneous resolution without intervention within several years. (Only if small)
Non-ossifying Fibroma morphology
Often appear in a pinwheel pattern w/ macrophages forming clusters and appearing like giant cells.
Radiographs show oval radiolucency with long axis parallel to the cortex of the bone
Metastatic tumors in bones
The majority of cancer in bones are metastatic to the bone but do not originate in the bone.
In adults, more than 75% originate from prostate, breast kidney and lung cancers.
In children more than 75% originate from neuroblastoma, Wilms tumors and rhabdomyosarcoma
Pathways for metastatic tumor spread to bone
Direct extension
Lymphatic/hematogenous dissemination
Intraspinal seeding
Metastatic disease in bone morphology
Typically multifocal and involve the axial skeleton, especially the vertebral column.
Radiographs appear lyric (bone destroying) and/or blastic (bone forming)
Very poor prognosis
