neoblastic bone disease Flashcards by Emily Southall

tumour in popliteal fossa- why would this need an above knee amputation

want curative intent - cant just do excision, because tumour wraps itself around blood vessels and nerves in that area

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epidemiology of bone tumours

very rare
can be benign/malignant
much less common than lung ca
primary malignant bone tumours more common in young adults and children
commenst malignant bone tumour is metastatic

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site predilecation of bone tumours

osteosarcoma - around knee is most common

different tumours have different site and age predilection

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clinical presentation of bone tumour dx

pain
swelling
deformity
pathological fracture

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hx of bone tumour

age
site
duration
hx of trauma - can be misleading
multiple lesions - more likely metastatic or involve marrow like lymphoma
associated disease - wouldnt usually dx osteosarcoma in old, but if prev radiotherapy there, or Pagets disease consider it

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ix for bone tumour

XR
* site, size, margin
* solitary/multiple
* soft tissue extension - feature of malignancy
* associated disease/fracture

biopsy

if suspect - refer quickly to specialist cenytre

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where is the lesion

femur metaphysis

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describe this lesion

lytic - destroyed the cortex
extend to soft tissue

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biopsy for bone tumour

needle biopsy under radiological guidance with Jamshidi needle
+- US of CT guidance

open biopsy for sclerotic or inaccessible lesions only (ie if very bony and cant get needle in)

imprint (cytology) preparation - get dx in hrs about whether have representative tissue and whether benign/malignant

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describe this bone biopsy

some pre-existing host bone
some changes in marrow
it is malignant - no normal marrow tissue, trabecular bone is irregular, cartilage is in marrow. So whatever is goung on iss infiltrating bone

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benign conditions that mimic bone tumours

fibrous dysplasia
metaphyseal fibrois cortical defect/non-ossifying fibroma
reparative giant cell granuloma
ossifying fibroma
simple bone cyst

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summarise fibrous dysplasia

same bones and age as osteosarcoma

> female
mono-ostotic > polyostotic
1st 3yr of life
site - any bone, ribs, prox femur commonest
XR - soap bubble osteolysis

polyostotic disease associated with endocrine problems, and rough border cafe au lait spots (McCune Albright syndrome)

<1% malignant transformation

somatic mutation in guanine-nucleotide binding protein (G-protein) (GNAS mutation chr 20q13)

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XR for fibrodysplasia

soap bubble osteolysis
>1 bone
whereas osteosarcoma more likely one bone (unless met)

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histology of fibrodysplasia

marrow replaced by fibrous stroma
rounded and curved trabecular bone

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Rx of fibrodysplasia

can excise with a very small margin
no chemo

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sheperd’s crook deformity in fibrous dysplasia

when fibrodysplasia happens in femoral head

bone weak and cystic -> microfractures

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benign bone tumours

cartilaginous differentiation
* osteochondroma
* enchondroma
* chondroblastoma

bone forming
* osteoid osteoma
* osteoblastoma
* osteoma

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osteochondroma commonest sites

end of long bone
top of humerus
around knee

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pathology of osteochondroma

mimic tubular bone
have cartilaginous surface overling cortical and trabecular bone

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histology of osteochrondroma

cartilage on surface
bone underneath

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common sites for enchondroma

most in hands, some in feet
much less in long bones

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definition of enchondroma

proliferation of cartilige within bone

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XR of enchondroma

here in finger with pathological fracture

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Type of lesion in this enchondroma

popcorn calcification

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Describe this pathology of enchondroma

well circumscribed

is this benign or malignant

borderline considered to benign, but locally aggressive well demarcated eroded through cortex but hasnt burst through articular surface haemorrhage looks malignant

Summarise giant cell tumours

**borderline malignancy** site - epiphysis with metaphyseal extension age - 20-30yrs >female - XR - lytic - histology - osteoclasts on a background of spindle/ovioid cells **locally aggressive, can recur, can met** to lungs

Mx of giant cell tumour

excise with limited margin

site predisposition for giant cell tumour

made of osteoclast giant cells tumour cells are the stromal cells site - end of long bone, most around knee

XR of giant cell tumour

well demarcated expansile lesion can burst through cortex into surrounding tissue

histology of giant cell tumour

sheets of osteoclast giant cell

what is the most common malignant bone tumour

mets - but rare below elbow and knee

what mets to bone in adult

breast prostate lung kidney thyroid

what mets to bone in children

neuroblastoma Wilm's tumour osteosarcoma Ewings Rhabdomyosarcoma

how do you determine histologically where the mets have come from

stain - eg stain for PSA (prostate) immunohistological markers can tell you where met from

3 types of malignant bone tumours

osteosarcoma *(bone forming)* chondrosarcoma *(cartilage forming)* Ewing's sarcoma/PNET (primitive peripheral neuroectodermal tumour) *(undifferentiated mesenchymal tumour)*

Site predeliction for osteosarcoma

if older - jaw most - lower femur/upper tibia end of long bones

summarise osteosarcoma

mainly adolescence commonest primary bone sarcoma most around knee XR - metaphyseal, lytic, permeative, elevated periostium (Codman's triangle) histo- malignant mesenchymal cells +- bone and cartilage formation Rx - chemo, salvage surgery

Px of osteosarcoma

Px - poor. depend on: * how quickly detecte * whetehr in soft tissu * whether met * if more cartilage than bone hard to treat because not vascular so cant get chemo there

classification of osteosarcoma

according to site - intramedullary, intracortical, surface differentiation (grade) multicentricity ie synchronous or metachronus primary or secondary

what is codmans triangle

sclerotic and lytic lesion gone into the soft tissue pushed the periosteium up -> forming triangle called Codman's triangle

histopath of osteosarcoma

malignant bone mesenchymal stroma malignant cartilage too many cells - osteosarcoma, looser myxoid area, and disordered bone

touch preparation for osteosarcoma

malignant cells produce **alkaline phosphtase** (bone cells use this to mineralise bone) stain for this in core biopsy

summarise chondrosarcoma

malignant cartilage producing tumour 40yrs and older site - pelvis, axial skeleton, prox femur and tibia XR - lytic with fluffy calcification histo - malignant chondrocytes +- chondroid matrix may dedifferentiate to high grade sarcoma

px of condrosarcoma

**better than osteosarcoma** depend on grade and size

classification of chondrosarcoma

according to site - intramedullary, juxtacortical histologically - conventional (myxoid or hyaline), clear cell (low grade), dedifferentiated, mesenchymal

where is this lesion

arm tumour coming off the ulner into the soft tissue

describe this

humerus white glistening tumour lifted the periostium some benign here but some malignant chondrosarcoma because white, not as haemorrhagic as osteosarcoma

site prediliction from chondrosarcoma

most in pelvis end of long bone

histology for chondrosarcoma

cartilaginous tumour malignant cell in matrix atypical chondrocytes (usually purple/blue)

Summarise Ewing's sarcoma

highly malignant small round cell tumour usually < 20yrs site - diaphysis/metaphysis of long bones, pelvis XR - onion skinning of periosteum, lytic +- sclerosis histo - sheets of small round cells Px - 75% associated with specific chr translocation 11:22 (EWS/Fli1) - dx molecularly

site prediliction for ewing's sacoma

pelvis diaphysis of long bone

histology of ewings sarcoma

small round blue cell tumour

what do you have to exclude and how when dx ewings sarcoma

immunostaining Ewings will be +ve for MIC2

cytology of Ewing's sarcoma

alk phos -ve stains for CD99 or MIC2

genetics of Ewing sarcoma

t(11;22)(q24;q12) maling EWSR1-FLI1 fusion protein can detect protein to make dx

definition of soft tissue sarcoma

mesenchymal proliferations which occur in extraskeletal, non-epithelial tissues of the body - excluding meninges and lymphoreticular system

summarise soft tissue tumours

site - anywhere, large musches of extremities, chest wall, mediastinum, retroperitonium any age - mainly older men more Ewings and clear cell are more common in afrocaribbean

aetiology of soft tissue tumours

unknown genetic chemic carcinogens physical - asbestos, foreign body virus immunodeficiency

type of soft tissue carcinoma

**myxoid** - eg liposarcoma **spindly type** - spindle cell sarcoma - tumour of nerve/muscle **pleomorphic** - dont know where come from **epithelioid** - resemble carcinoma

ddx of spindle cell tumour