Histo: Neoplastic Bone Disease Flashcards
Which part of the body is most commonly affected by neoplastic bone disease?
Around the knee joint
Outline some presenting features of neoplastic bone disease.
- Pain
- Swelling
- Deformity
- Fracture
How are bone tumours diagnosed
X-ray
Biopsy
What type of biopsy is often used for diagnosing neoplastic bone disease?
- Needle biopsy using a Jamshidi needle under CT or US guidance
- Open biopsy for sclerotic or inaccessible lesions
List some tumour-like conditions of the bone.
- Fibrous dysplasia
- Metaphyseal fibrous cortical defect/non-ossifying fibroma
- Reparative giant cell granuloma
- Ossifying fibroma
- Simple bone cyst
What is fibrous dysplasia? Which age does it affect? What bone does it affect?
- Condition in which fibrous tissue replaces normal bone tissue
- Can occur in any bone but ribs and proximal femur is most common
- Tends to affect adolescents
Which eponymous syndrome is characterised by polyostotic fibrous dysplasia?
McCune Albright Syndrome: polyostotic fibrous dysplasia + endocrine problems + rough border café-au-lait spots
Which mutation causes fibrous dysplasia?
GNAS mutation Chr 20 q13 (mutation in a G-protein)
Describe the histological appearance of fibrous dysplasia.
The marrow is replaced by fibrous stroma with rounded trabecular bone (‘Chinese letters’)
Describe the deformity seen on X-ray of fibrous dysplasia of the femoral head. What other lesion might you see?
Shepherd’s crook deformity
Soap bubble appearance of lytic lesions
List three types of cartilaginous benign bone tumour.
- Osteochondroma
- Enchondroma
- Chondroblastoma
List three types of bone-forming benign bone tumour.
- Osteoid osteoma
- Osteoma
- Osteoblastoma
What are osteochondromas and which bones tend to be affected?
- A benign overgrowth of cartilage and bone that tends to happen at the ends of long bones
- Most common site is distal end of femur
- They mimic normal tubular bone as they have a cartilaginous surface overlying normal trabecular bone
What is an enchondroma and which bones tend to be affected? What may an XR show?
- A cartilaginous proliferation within the bone
- Most tend to be found in the hands and can cause pathological fractures
- X-ray may show popcorn calcification
What are two macroscopic features of benign bone tumours?
- Well demarcated
- May erode through the cortex of bone but does not burst through the cartilaginous surface
What are giant cell tumours? Where do they tend to be found and what is their histological appearance?
- Benign tumour of the bone characterised by the presence of lots of osteoclast giant cells
- They tend to be found at the ends of long bones (epiphysis)
- It has a lytic appearance on X-ray
- Histology shows many osteoclasts on a background of spindle/ovoid cells
- Borderline malignancy - locally aggressive, can metastasise
What is the most common type of malignant bone tumour?
Metastases
Which cancers in adults tend to spread to the bone?
- Breast
- Prostate
- Lung
- Kidney
- Thyroid
Which cancers in children tend to spread to the bone?
- Neuroblastoma
- Wilm’s tumour
- Osteosarcoma
- Ewing’s sarcoma
- Rhabdomyosarcoma
List three types of malignant primary bone tumour. Which is the most common?
- Osteosarcoma (most common)
- Chondrosarcoma
- Ewing’s sarcoma/PNET
What is an osteosarcoma, what age group is it most common in, and where does it tend to affect?
- Malignant bone-forming tumour of the bone that mainly occurs at the ends of long bones
- Tends to occur at age 10-30 years (incidence peaks in adolescence)
- 60% affect the knee
Describe the X-ray appearance of osteosarcoma
- Usually metaphyseal
- Lytic
- Permeative
- Elevated periosteum (Codman’s triangle)
Describe the histological appearance of osteosarcoma.
- Lots of malignant osteoblast cells with or without bone and cartilage formation
NOTE: this can be stained for using ALP
How can osteosarcoma be classified?
- Site within the bone (intramedullary, intracortical, surface)
- Degree of differentiation (high, intermediate, or low grade)
- Multicentricity
- Primary or secondary
What is a chondrosarcoma? Which age group does it affect? What bones does it affect?
- Malignant cartilage-producing tumour
- Tends to occur in patients aged > 40 years
- Affects axial skeleton, proximal femur and proximal tibia
Describe the X-ray appearance of chondroscarcoma.
Lytic with fluffy calcification
Describe the histology of chondrosarcoma
Malignant chondrocytes +/- chondroid matrix
List the histological subtypes of chondrosarcoma.
- Conventional (myxoid or hyaline)
- Clear cell (low grade)
- Dedifferentiated (high grade)
- Mesenchymal
NOTE: myxoid = composed of clear, mucoid substance
What is an Ewing’s sarcoma? What ages does it predominantly affect? What bones does it affect?
- Highly malignant tumour arising from neuroectodermal cells (small round cell tumour)
- Typically occurs in people < 20 years old
- Mainly affect diaphysis and metaphysis of long bones, pelvis
Describe the X-ray appearance of Ewing’s sarcoma.
- Onion skinning of the periosteum
- Lytic with or without sclerosis
Describe the histological appearance of Ewing’s sarcoma.
Sheets of small round cells
Which genetic abnormality is associated with Ewing’s sarcoma?
Chromosomal translocation 11;22 (EWSR1/FLI1) (q24:q12)
Describe the prognosis of osteosarcoma, chondrosarcoma, and Ewing’s sarcoma
Osteosarcoma: 60% 5 year survival
Chondrosarcoma: 70% 5 year survival
Ewing’s: 75% 5 year survival
Define soft tissue tumour.
Mesenchymal proliferations which occur in the extra-skeletal, non-epithelial tissues of the body - excluding meninges and lymphoreticular system
Where do soft tissue tumours occur and which age group do they predominantly affect?
Anywhere - majority occur in large muscles of extremeites, chest wall, mediastinum, retroperitoneum
Predominantly affect >55 years
List three types of soft tissue tumour.
- Liposarcoma
- Spindle cell sarcoma
- Pleomorphic sarcoma
List some special diagnostic techniques used to diagnose soft tissue tumours.
- Immunohistochemistry
- Electron microscopy
- Cytogenetic
- FISH
- RT-PCR
List some bad prognostic factors for soft tissue tumours.
- > 5 cm size
- Depth involving deep fascia
- High grade
- Involved excision margin
- Vascular invasion
- Ploidy (aneuploid/hyperdiploid)
- High proliferation index
- Absent tumour suppression genes
- Present tumour promotor genes
Which conditions have these following X-ray features:
- soap bubble lytic lesions
- shepherd’s crook
- popcorn calcifications
- Codman’s triangle
- lytic with fluffy calcifications
- periosteal onion-skinning
- fibrous dysplasia, giant cell tumour of bone
- fibrous dysplasia
- enchondroma
- osteosarcoma
- chondrosarcoma
- Ewing’s sarcoma
