Histopathology - Bone tumours Flashcards
What is the preferred investigation for diagnosing bone tumours?
US guided Jamshidi needle biopsy
What is “shepherd’s crook deformity” a reference to?
Fibrous dysplasia involving the femoral head
Recall 7 benign conditions of the bone
Fibrous dysplasia
Osteoma
Osteoid osteoma
Osteoblastoma
Simple Bone cyst
Enchondroma - Cartilaginous
Osteochondroma - Cartilaginous
How does osteochondroma mimic bone in appearance?
They have a cartilaginous surface overlying normal cortical + trabecular bone
In which bones is osteochondroma most likely to present?
Long bones
How will enchondroma appear on XR?
“popcorn” pattern
Is a giant cell tumour of bone benign or malignant?
Borderline malignant
How do giant cell bone tumours appear under the microscope & XR?
Osteoclasts on a background of ovoid cells
common in females aged 20-40
-XR shows lytic apperance
What are the 3 types of malignant bone tumour?
Osteosarcoma (bone-forming)
Chondrosarcoma (cartilage-forming)
Ewing’s sarcoma (undifferentiated mesenchymal)
Recall the typical age of presentation for each of the 3 types of malignant bone tumour
Osteosarcoma: adolescence
Chondrosarcoma: >40 years
Ewing’s sarcoma: <20 years
Recall the typical site affected for each of the 3 types of malignant bone tumour
Osteosarcoma: knee
Chondrosarcoma: pelvis/ axial & femur/tibia skeleton
Ewing’s sarcoma: long bones + pelvis
Recall the typical X ray appearance of each of the 3 types of malignant bone tumour
Osteosarcoma: Codman’s triangle, Sunburst appearance
Chondrosarcoma: fluffy calcification
Ewing’s sarcoma: Onion-skinning of periosteum
What is a “Codman’s triangle”?
The triangular area of new subperiosteal bone that is created when a lesion, often a tumour, raises the periosteum away from the bone.
Which of the 3 types of malignant bone tumour has the best prognosis?
Chondrosarcoma
What gene mutation is associated with Ewing’s sarcoma?
11:22 translocation
Which type of malignant bone tumour will stain for CD99 and MICC2?
Ewing’s sarcoma
Which patients are most at risk of developing Ewing’s tumour in soft tissue?
Immunocompromised patients
where in body is common affected in enchondroma? What age group too
Hands
Middle aged
2 XR findings of fibrous dysplasia?
soap bubble osteolysis
shepherds crook deformity (femoral head)
bone will appear histologically normal in what 2 benign conditions
osteoid osteoma
osteoma
is osteoid osteoma more common in M or F
M (2:1)
is fibrous dysplasia more common in M or F
F
(f for fibrous)
McCune albright syndrome is related to what benign condition? what’s the triad
McCune albright = polyostotic fibrous dysplasia + cafe au lait spots + precocious puberty
mushroom appearance on XR =
Osteochondroma
looks like a bony projection on the external surface of a bone, like a bony mushroom on a stalk, usually near a growth plate area
what’s the most common benign tumour of bone. What age
Osteochondroma
Adolescent
XR finding of osteoid osteoma
radiolucent nidus w sclerotic rim = bulls eye
histological appearance of bone in fibrous dysplasia
woven bone with odd irregular shapes (often described as “chinese characters”)
outline 4 differences between benign and malignant bone conditions
benign = no peirosteal reaction, acute reaction in malignant (codmans's, onion ski, sunburst appearance) benign = well developed bone formation, malignant = varied bone formation benign = intraossesu and even calcification, malignant = extraosseus and irregular calcification
