Bone tumors Flashcards
What are the different classification of bone tumor?
1) Primary bone tumor (originate in the bone itself):
- Benign (non-cancerous)
- Malignant (cancerous)
2) Secondary bone tumor (metastatic), when cancer cells from other parts of the body spreads into the bone (more common than primary)
Cancer of which organ is most likely to metastasize and spread into the bone?
1) Breast
2) Lung
3) Prostate
4) Kidney
5) Thyroid
What are the benign and malignant bone forming tumors in primary bone tumors?
Benign:
1) Osteoma
2) Osteoid osteoma
Malignant:
1) Osteosarcoma (both primary & secondary)
What are the benign and malignant cartilage forming tumors in primary bone tumors?
Benign:
1) Osteochondroma
2) Chondroma
3) Chondroblastoma
4) Chondromyxoid fibroma
Malignant:
1) Chondrosarcoma
What are the benign and malignant miscellaneous tumors in primary bone tumors?
- Those cancers do not fit into the common categories of bone tumors
Benign:
1) Giant cell tumor
Malignant:
1) Ewing’s sarcoma
- Less common, usually arise from neural, adipocytic, smooth muscle lineage and uncertain lineage
What are the malignant myelogenic tumors in primary bone tumors?
- Arises from blood and bone marrow
1) Lymphoma
2) Leukemia
3) Multiple myeloma
What are the benign and malignant fibrogenic tumors in primary bone tumors?
Benign:
1) Fibroma
Malignant:
1) Fibrosarcoma
What are the benign and malignant bone tumors with a histiocytic origin in primary bone tumors?
- Refers to a tumor that arises from histiocytes, which are a type of immune cell derived from the bone marrow
Benign:
1) Benign fibrous histiocytoma
Malignant:
1) Malignant fibrous histiocytoma
What are the malignant notochordal tumors in primary bone tumors?
Chordoma
Describe osteoma’s
- Benign bone tumors
- Arises on the surface of cortical bone
- Grows slowly, looks rounded and well-circumscribed
- Appears like a bony projection on the surface of the bone
In which age group and sex is osteoma more common?
1) 40-50
2) Males
Where does osteoma arise?
1) Surface of the cortex
2) More common in bones with intramembranous ossification (craniofacial) than long bones
3) Inner and outer table of the skull
4) Mandible and maxilla
5) Air sinuses (frontal-ethmoid)
What are the radiologic features of osteoma?
1) Usually rounded
2) It is radio-dense (appears white)
What are the gross characteristic of bone tumors?
1) Exophytic (growing outwards) sessile (directly attached to the bone) mass
2) Tan - White color
3) Round to oval
What is the microscopic pathology of osteoma?
Mature, dense, compact cortical bone (woven “immature” & lamellar “mature”)
Give me a mnemonic that summarizes osteoma
1) O: Oval, On the cortex
2) S: Sessile
3) T: Table of the skull, Tan-white
4) E: Exophytic
5) O: Opaque (Radio-dense)
6) M: Mandible, Maxilla, Mature (normal bone), Males
7) A: Air sinuses
Describe osteoid osteoma
- Small, benign neoplasm
- Evokes severe pain (more at night, and it is relieved by aspirin)
What are the common age group and sex for osteoid osteoma?
1) 20-30 years
2) Males
What is the site of osteoid osteoma?
Metaphysis of long bones (cortex), like the femur and tibia
What is the radiological finding of osteoid osteoma?
1) Small radiolucent focus (nidus may or may not have central densities (osteoid tissue))
2) Surrounded by a sclerotic zone (appears as an increased bone density and mineralization)
3) Well circumscribed
4) Described as a radiolucent lesion called nidus because it looks like a nucleus of a cell. It represents the unmineralized osteoid tissue, if the nidus calcifies it will appear more dense (central density)
At which time of the day is the pain aggravated in osteoid osteoma?
At night (hall mark symptom), due to the release of prostaglandins and inflammatory mediators
- Released by the use of aspirin and NSAID’s
Describe the naked eye appearance of osteoid osteoma
1) Small rounded mass usually 1-cm
2) Well circumscribed
3) Hemorrhagic and gritty “rough texture, as if it is coated with sand” (This is why it appears red, it could also appear brown depending on the age of the tumor)
- The lesion feel tough and gritty due to the presence of unmineralized osteoid tissue
4) Surrounded by a sclerotic zone
Describe the microscopic picture of osteoid osteoma
1) Interlacing trabeculae of woven bone rimmed by osteoblasts
2) Loose vascular connective tissue stroma
Describe osteoblastoma (giant osteoid osteoma)
- Similar to osteoid osteoma (both are benign)
- Osteoblastomas are usually called giant osteoid osteomas, but the site differs
- The pain it causes is not relieved by NSAIDs
What is the common age and sex of osteoblastoma (giant osteoid osteoma)?
1) 20-30 years
2) Males
What is the common site of osteoblastoma (giant osteoid osteoma)?
Spinous & transverse process of the medulla of the vertebral column
Describe the microscopic picture of osteoblastoma (giant osteoid osteoma)
1) The connective tissue stroma is more compact
2) The RBC could be free, inside or outside the blood vessels
What is the difference between osteoid osteoma and osteoblastoma?
1) Location:
- Osteoid osteoma (metaphysis of femur and tibia)
- Osteoblastoma (Vertebral column)
2) Age:
- Osteoid osteoma (10-20 years)
- Osteoblastoma (10-20 years)
3) Morphology:
- Osteoid osteoma (cortical tumors, pain, interlacing tubercle of woven bone)
- Osteoblastoma (vertebral transverse and spinous processes, histologically similar to osteoid osteoma)
4) General:
- Osteoid osteoma (smaller, relieved by aspirin, common in the cortex and metaphysis of long bones, has sclerotic zones)
- Osteoblastomas (larger, nor relieved by aspirin, lacks sclerotic zone)
Describe osteosarcoma
Malignant tumor of mesenchymal cells characterized by direct formation of osteoid bone matrix by the tumor cells
- There is two types:
1) Primary osteosarcoma (de novo from the bone), most common malignancy in children
2) Secondary osteosarcoma (due to radiation or chronic diseases “like Paget’s or osteomyelitis) more common in older age group
What are the risk factors of osteosarcoma?
1) Paget’s disease
2) Radiation
3) Infarction of bone
4) Male
5) Alcohol and poor diet
6) Retinoblastoma
7) 10-20 years
What is microscopic picture of osteosarcoma?
It is pinkish and glassy in appearance
What is the incidence of primary (conventional) osteosarcoma?
The most common primary malignant bone tumor in children
What is the common age and sex of primary (conventional) osteosarcoma?
1) 20 years
2) Males
Describe the pathogenesis of primary osteosarcoma
Genetic factors: Mutations in retinoblastoma gene, TP53
- Retinoblastoma gene is a tumor suppressing gene, a mutation in it predisposes osteosarcoma
- Retinoblastoma and p53 are central tumor suppressors and are often found inactivated in various tumor types
What is the mode of growth of osteosarcoma?
- Aggressive tumor invading:
1) Inwards: medullary cavity
2) Outwards: destroys the cortex, invades adjacent soft tissue
3) Spared epiphyseal cartilage (cannot invade cartilage): rarely involves joints
What are the common sites of primary osteosarcoma?
- Metaphysis of long bones (growing area)
- 60% around the knee
1) Lower end of femur
2) Upper end of the tibia
3) Proximal humerus
4) Proximal femur
What is the characteristic of ostesarcoma?
- Formation of new bone (in two distinct patterns):
1) Subperiosteal bone formation:
- New bone formation occurs beneath the periosteum, elevating the periosteum forming the characteristic code’s man triangle
2) Radiating new bone formation:
- New bone forms within the tumor itself, radiating from the central area outwards
Describe the naked eye appearance of primary osteosarcoma
1) Large bulky mass
2) Metaphysis of long bones
3) Fusiform and fading away on the shaft (mutton leg “sheep leg”) like a balloon
4) Greyish-white, fish-flesh
5) Hge (hemorrhage, cancers like osteosarcoma often outgrows their blood supply, leading to insufficient oxygen and nutrient delivery = necrosis) & Necrosis
- Necrotic areas can fall off and leave a cystic area behind them
6) New bone formation:
- In subperiosteal area
- Radiates from the central mass
What are the gross/macroscopic features of primary osteosarcoma?
1) Hemorrhage
2) Grey-brown lesion
3) Pathological fracture
Describe the microscopic picture of osteosarcoma
1) Osteoblastic areas:
- Spindle shaped cells
- Pleomorphism (different forms and sizes) & many mitotic figures
- Osteoid formation: pink glassy homogeneous (can contain calcification “if dystrophic it appears dark”)
2) Chondroblastic areas
3) Fibroblastic areas
What are the radiological features of primary osteosarcoma?
1) Destruction of the bone
2) New bone formation
- Subperiosteal (code man’s triangle)
- Fine spicules of bone radiating from a central mass parallel to the blood vessels
3) Sun burst appearance
What is the clinical picture of primary osteosarcoma?
1) The mass progressively enlarges
2) Pathological fracture
3) Pain
How does primary osteosarcoma spreads?
1) Directly
2) Hematogenous (from lung, liver, bone, brain, etc)
What is the prognosis of primary osteosarcoma?
Depends on:
1) Age
2) Mutations
3) Stage of the tumor (including its size)
4) Nodules status
5) Metastasis
6) Grading and differentiation of the mass
What is a secondary osteosarcoma?
1) Common in old people >40 years
2) Occurs in flat bones mainly (important to differentiate between it and primary)
3) Causes:
1. Ionizing radiations (radiotherapy/ post-irradiation bone sarcoma)
- Pre-existing bone lesions like:
1) Paget’s
2) Bone infarct (ischemic death of the cellular elements of the bone and marrow)-fibrous dysplasia (when abnormal fibrous tissue replaces the healthy ones)
3) Chronic osteomyelitis (bone infection that does not go away with treatments)
What are the different cartilage forming tumors?
- They synthesize cartilage as their matrix
1) Benign:
1) Osteochondroma
2) Chondroma
2) Malignant:
1) Chondrosarcoma
What is osteochondroma?
It is a benign tumor that protrudes from the mature bone which is capped by the growing cartilage from the outer contour of the affected bone
What is the rate of incidence, age and sex related to osteochondroma?
It is the commonest benign bone neoplasm (1/3 of benign tumors), affects males way more, affects individual between 20-30 years
What is the site where osteochondroma mainly occurs?
1) Metaphysis near growth plate
2) Knee: lower femur / upper tibia
describe the gross appearance of osteochondroma
1) Mushroom shaped
2) Mature cortical and medullary bone capped by hyaline cartilage
3) Grow away from near by joint
4) The cartilage looks bluish
What is osteochondromatosis?
1) Multiple osteochondromas
2) Autosomal dominant
3) Increases the incidence of malignant transformation
Describe enchondroma
1) Benign tumor cartilage that arises from the metaphysics of small bones
2) Occurs within the medullary cavity
3) Stains and appears blue in color
4) Semi-transluent, small and benign
What is the common age and sex of enchondroma
1) 20-40 years
2) Both males and females
What is the common site of enchondroma?
1) Small bones of the hand and feet (metaphysics of phalanges and metacarpals)
2) Long bones: Humerus & femur
Describe the naked-eye appearance of enchondroma
1) Well circumscribed
2) Blue
3) Semitranslucent
4) <3 cm
Describe the microscopic photo of the enchondroma?
1) Hypocellular, avascular tumors (lacking blood vessels, contributes to their slow growth and stable nature)
2) Abundant blue hyaline cartilage matrix
3) The chondrocytes are situated within lacunar spaces
4) Chondrocytes have small and round nuclei
5) Lobules of cartilage
6) They are small, uniform, and do not show atypia
7) The masses are hypocellular meaning they have few cells compared to normal tissue or other tumors
What is chondrosarcoma?
1) Malignant cartilage forming tumor
2) Second most common tumor after osteosarcoma in old age
3) It is secondary to osteochondromatosis and enchondromatosis
What is the incidence of chondrosarcoma?
1) The second most common malignant bone tumor
2) Primary/secondary to osteochondromatosis or enchondromatosis
T3) he transformation of enchondroma or osteochondromas in enchondromatosis or osteochondromatosis, respectfully, leads to the development of chondrosarcomas secondary to these conditions
4) Chondrosarcomas could also be primary meaning that they arise on their own and not from other bone tumors.
What is the common age for chondrosarcoma?
40-60 years
What is the site where chondrosarcoma mostly occurs?
1) Central skeleton (axial)
2) 50% in pelvic girdle
3) Shoulder girdle and ribs
4) May affect long bones around the knee
Describe the naked-eye appearance of chondrosarcoma
1) Large
2) Irregular-lobulated contours
3) Bluish-white
4) Semi-translucent
5) Firm with gelatinous areas
6) Focal necrosis and calcification (death tissue within the tumor mass)
7) Invasive and grows in a non-uniform manner
Describe the microscopic photo of chondrosarcoma
1) It can be both well and poorly differentiated
2) Cells show atypia (moderate atypia is well-differentiated, while severe atypia is poorly differentiated)
3) In poorly differentiated they also present with spindle-cells (looks like it), while the well-differentiated might be mistaken with benign tumors
Describe the mode of chondrosarcoma growth
1) Arises within the medullary cavity
2) Erodes the cortex to the surrounding soft tissue
Describe the X-ray appearance of chondrosarcoma
1) Destruction of the medullary and cortical bones
2) Mottled densities (dense areas in the affected bone “calcification”)
3) Extraosseous extension
How does chondrosarcoma spread in the body?
- By:
1) Lung
2) Liver
3) Bone
Describe giant cell tumor
- Benign, but locally aggressive tumor
- It usually affects individuals with age 25-40 years, and females more than males
- They should be excised as they destruct the tissue
What is the common affected site in giant cell tumors?
1) Epiphysis of long bones
2) 50% around the knee (upper tibia lower femur)
3) Upper humerus
4) Lower radius
Describe the gross appearance of giant cell tumor of the bone
1) Large
2) Red-brown
3) Destroyes the cortex
4) Contains both necrotic and cystic changes
5) You can find remnants of residual bony trabeculae
6) Thin shell of subperiosteal reactive bone
7) Soap-bubble appearance in the X-ray due to the manifestations of the cystic fibrosis (develops fluid-filled cavities within the tumor mass giving the soap-bubble appearance)
How does the soap-bubble appearance happen in a giant cell tumor?
1) Bleeding within the tumor can form blood-filled cysts
2) Areas of necrosis within the tumor might liquefy forming fluid-filled cysts
3) Certain components of the tumor might undergo degenerative changes forming cystic spaces
Describe the radiological features of giant cell tumor
1) Large osteolytic (bone dissolving) lesions + the remnants of bone trabeculae traversing the lesion = soap bubble
2) Destroyed cortex
3) Thin shell of reactive new bone
4) Might extend to soft tissues or into the joint space through the articular cartilage (unlike osteosarcoma which are cartilage-sparing)
Describe the microscopic photo of a giant cell tumor
1) Mononuclear stromal cells
- Neoplastic rounded to spindle vesicular nuclei
2) Multinucleated giant cells
- Reactive - large number 50-100 vesicular nuclei that are evenly distributed
3) Scanty stroma + Hge, necrosis
What is Ewing’s sarcoma?
- Malignant neoplasm of the bone
- Originates from undifferentiated neuro-ectodermal cells
- Mainly affects children and adolescents 10-15 years
- Occurs usually secondary to osteosarcoma
- Affects more males 2:1
- Caused by the translocation of EWS genes
What are the common sites of ewings sarcoma?
1) Diaphysis of long bones more than flat bones
2) 50% around the knee (tibia, femur and fibula)
3) Medullary cavity to the cortex to soft tissues
Describe the naked-eye appearance of Ewings sarcoma
1) Tan-white
2) Contains Hge & necrosis
3) Arises in the medullary cavity and the invades the cortex and soft tissue
Describe the microscopic photo of Ewing’s sarcoma
Sheets of small round blue cells, dark nucleus, scanty cytoplasm & contains glycogen & pseudo-rosettes (resemble true rosettes but lack a central core or lumen. Instead, the cells appear to be arranged in a circular or radial pattern without a central structure)
Describe the radiological features of Ewings sarcoma
1) Arises from the medullary cavity of the diaphysis
2) Invades the cortex into the surrounding soft tissue
3) One of its characteristic features is the onion skin densities (results from the formation of multiple layers of reactive new bone around the tumor)
4) Sometimes we see the hair-on-end appearance. It may be observed if the tumor extensively invades the bone marrow, causing disruption and remodeling of the trabecular bone
What are the clinical features of Ewings sarcoma?
1) Pain
2) Swelling
3) Heat
4) Fever
- It has an aggressive prognosis and a survival rate of over 75%
- It can metastasize into the lung, skull, and flat bones
What is the route of the most common malignant bone tumors?
Hematogenous
What is the most common site of the most common malignant bone tumors?
1) 70% axial skeleton (cranium, spine, ribs & sacrum)
2) 30% metaphysis of long bones (upper femur)
What are the most common primary metastatic tumors in adults?
1) Prostate
2) Breast
3) Kidney
4) Lungs
5) Thyroid
What are the most common primary metastatic tumors in children?
- The examples for children’s primary tumors are all small round blue cell tumors
1) Neuroblastoma
2) Wilm’s tumors
3) Osteosarcoma
4) Ewing’s sarcoma
5) Rhabdomyosarcoma
What are the different classifications of metastatic tumors?
1) Osteolytic (destructive):
- Osteolytic tumors, on the other hand, cause the destruction or resorption of bone tissue, resulting in weakened bone structure
- Breast
- Thyroid
- Kidney
- Lung
- GIT
2) Osteosclerotic/osteoblastic (reactive bone formation:
- Osteoblastic tumors are characterized by excessive bone formation, leading to the thickening or overgrowth of bone tissue
- Prostate
3) MIXED (osteolytic and osteosclerotic):
- Most tumors, usually with multiple patterns
What is the most common form of skeletal malignancy?
Metastatic tumors
What are the subdivisions of the major tumor types?
A) Benign neoplasm:
1) Osteoid osteoma (island of woven bone, typically involves the proximal femur or tibia)
2) Osteochondroma (cartilage-capped outgrowth at epiphyseal growth plate)
3) Enchondroma (nodules of hyaline cartilage)
4) Giant cell tumor (composed of a mixture of neoplastic mononuclear cells and osteoclast-like giant cells, typically occupies long bone epiphysis)
B) Malignant neoplasm:
1) Osteosarcoma (malignant mesenchymal tumor forming bone “it ius 20% of primary bone tumor”)
2) Chondrosarcoma (malignant mesenchymal tumor forming cartilage)
3) Ewing’s sarcoma (Aggressive small round cell tumor of adolescents with EWS gene rearrangement)
What is the difference between benign and malignant tumors?
Benign:
1) Well-defined, sclerotic border
2) Lack of soft tissue mass
3) Solid periosteal reaction
4) Geographic bone destruction
Malignant:
1) Interrupted periosteal reaction
2) Moth-eaten/primitive bone destruction
3) Soft tissue mass is available
4) Wide zone of transission
