Pathology Flashcards
(35 cards)
What are the prognostic factors in bone tumour staging?
In order
- Presence of metastases
- Discontinuous tumour (skip lesion)
- High grade (poorly differentiated)
- Size
- Depth
What are the prognostic factors in soft tissue tumour staging?
In order
- Presence of metastases
- Grade
- Size
- Depth
Most common site of metastasis from bone lesions and soft tissue sarcomas?
Lung
Chemotherapy is used to reduce or eliminate pulmonary mets by inducing apoptosis (programmed cell death)
What is an osteotomy osteoma?
Definition:
A benign bone tumour with a central nidus (woven bone and osteoid with greatest mineralisation in centre, and sharp border of osteoblastic rimming) surrounded by a reactive zone (sclerosis)
Histology:
- Mineralised woven bone
- Regularly shaped nuclei containing little chromatin
- Abundant cytoplasm
- Appearances similar to osteoblastoma
Epidemiology:
- Typically < 30 years old
- M:F 3:1
Locations:
-Usually within diaphysis and cortex
-Prox femur > tibia>
Spine >hands (scaphoid and prox phalanges)>feet (talar neck)
Symptoms:
-Pain at night, increases with time
-Secondary to prostaglandin E2 prod and COX1/COX2 expression
= increase in number/size of unmyelinated nerve fibres within nidus
-Relieved by NSAIDS
Associated conditions:
- Painful scoliosis, concave on lesion side (remove within 18 months in children < 11 years old)
- Growth disturbances
- flexion contractures
Diagnosis:
- CT better than MR scan
- Nidus < 1 cm (otherwise osteoblastoma)
- Technetium bone scan = increased uptake
Treatment
- 50% improve with NSAIDS
- CT-guided radiofrequency ablation dominant treatment method (nidus heated to 80 degrees)
- Surgery is near NV bundle/spinal cord (RFA contraindicated)
Prognosis:
- Pain resolves in 3 years
- Lesions spontaneously resolve in 5-7 years
Histology of osteoid osteoma?
Histology:
- Mineralised woven bone
- Regularly shaped nuclei containing little chromatin
- Abundant cytoplasm
- Appearances similar to osteoblastoma
Epidemiology and location of osteoid osteoma
Epidemiology:
- Typically < 30 years old
- M:F 3:1
Locations:
-Usually within diaphysis and cortex
-Prox femur > tibia>
Spine >hands (scaphoid and prox phalanges)>feet (talar neck)
Which bone tumours and which soft tissue tumours is chemotherapy particularly used?
Adjuvant to limb salvage surgery for bone tumours
- Osteosarcoma
- Ewing’s sarcoma
Soft tissue tumours
- Rhabdomyosarcoma
- Synovial sarcoma
How does radiotherapy work and when is it used?
And what are the bony complications?
Radiotherapy reduces or eliminates local recurrence by inducing DNA damage
Radiotherapy used ALONE for:
- Metastatic bone disease
- Lymphoma
- Myeloma
- Sometime Ewing’s sarcoma
Radiotherapy used in COMBINATION with limb salvage surgery for:
- Soft tissue sarcomas
May be used PRE or POST operative. Post op = - Equal control rates - Lower wound complications - Higher incidence of post operative fibrosis
Bony complications:
- Late stress fractures
- Post-irradiation sarcomas
When is wide excision used alone?
- Chondrosarcoma
- Parosteal Osteosarcoma
- Adamantinoma
- Chordoma
When is intralesional resection/curettage used?
- Giant cell tumour
- Chondroblastoma
- Osteoblastoma
- Non-ossifying fibroma
- ABC
- LCH (Langerhan’s cells histiocytosis)
How do benign bone tumours in children usually present?
Incidental finding
Commonest bone tumours by age?
< 5 years
< 30 years
> 50 years
< 5 years
- Leukaemia
- Osteofibrous dysplasia
- Rhabdomyosarcoma
< 30 years
- NOF (non-ossifying fibroma)
- UBC (unicameral bone cyst)
- Enchondroma
- Osteoid osteoma
- Fibrous dysplasia
- Chondroblastoma
- GCT (giant cell tumour)
- Ewing’s sarcoma
- Osteosarcoma
> 50 years
- Bony mets
- Myeloma / Lymphoma
- Chondrosarcoma
- Fibrosarcoma
- Malignant fibrous histiocytoma
- Paget’s disease
Tumours associated with anterior cortex?
Osteofibrous dysplasia
Adamantinoma
Tumours associated with posterior cortex of distal femur?
Parosteal osteosarcoma
Periosteal desmoid (aka tug lesion caused by repetitive stress at attachment of adductor magnus)
Which tumours present in the epiphysis?
GCT
Chondroblastoma
Clear cell Chondrosarcoma (femoral head)
Which tumours present in the metaphysis?
Non-ossifying fibroma
ABC
Osteosarcoma
Which tumours present in the diaphysis?
Osteoid osteoma Osteoblastoma Fibrous dysplasia Eosinophilic granuloma Ewing’s sarcoma Multiple myeloma
Symptoms and associated conditions of osteoid osteoma
Symptoms:
-Pain at night, increases with time
-Secondary to prostaglandin E2 prod and COX1/COX2 expression
= increase in number/size of unmyelinated nerve fibres within nidus
-Relieved by NSAIDS
Associated conditions:
- Painful nonstructural scoliosis, concave on lesion side (remove within 18 months in children < 11 years old). Occurs due to paraspinal muscle spasm
- Growth disturbances
- flexion contractures
Imaging of osteoid osteoma
Diagnosis:
- CT better than MR scan
- Nidus < 1 cm (otherwise osteoblastoma)
- Technetium bone scan = increased uptake
Treatment and prognosis of osteoid osteoma
Treatment
- 50% improve with NSAIDS
- CT-guided radiofrequency ablation dominant treatment method (nidus heated to 80 degrees)
- Surgery is near NV bundle/spinal cord (RFA contraindicated)
Prognosis:
- Pain resolves in 3 years
- Lesions spontaneously resolve in 5-7 years
What are the principles of biopsy?
- Use longitudinal incisions and excise the biopsy tracts
- Maintain meticulous haemostasis (tourniquet, diathermy). Only in rare cases use small drain in corner of wound to prevent haematoma formation
- Approach lesions through muscles if possible
- Avoid functionally important and NV structures
- Intraoperative frozen section analysis should be performed to ensure that adequate diagnostic tissue is obtained
- Samples should be sent for bacteriologic analysis
What are the 4 surgical margins of tumour excision?
1) Intralesional
2) Marginal (through reactive zone)
3) Wide (including a cuff of normal tissue)
4) Radical (entire tumour and its compartment removed, including surrounding muscles, ligaments and connective tissues)
What are the 2 essential criteria for limb salvage surgery?
- Outcome of local control is at least equal to that of amputation
- Limb must be functional
What tumours are associated with following genes?
Tumour suppressor genes (Retinoblastoma (RB) and p53)
t(11,22), gene product EWS-FLI1
t(X,18), gene product SYT-SSX1 and 2
t(12,16), gene product FUS-CHOP
t(2,13), gene product PAX3-FKHR
GNAS1 - activating mutation of the GS alpha surface protein
Tumour suppressor genes (Retinoblastoma (RB) and p53 - Li Fraumeni syndrome) = OSTEOSARCOMA
t(11,22), gene product EWS-FLI1 = EWING’S SARCOMA
t(X,18), gene product SYT-SSX1 and 2 = SYNOVIAL SARCOMA
t(12,16), gene product FUS-CHOP = MYXOID LIPOSARCOMA
t(2,13), gene product PAX3-FKHR = ALVEOLAR RHABDOMYOSARCOMA
GNAS1 - activating mutation of the GS alpha surface protein = FIBROUS DYSPLASIA
