The document discusses classification and staging of bone tumors. Enneking's surgical staging system classifies bone tumors based on their histological grade, location within the bone, and presence of metastases. The stages range from 1 to 3, with higher numbers indicating more advanced or aggressive tumors. Several benign and malignant bone tumors are also described in terms of their typical location, patient demographics, clinical and radiological appearance, pathology, treatment options, and prognosis.

4. Classification based on:
 Histological grade (G)
 Site (T)
 Metastases (M)
ENNEKING'S SURGICAL STAGES
STAGE GRADE SITE METASTASES
1A
1B
Low(G1)
Low(G1)
Intracompartmental(T1)
Extracompartmental(T2)
None(M0)
None(M0)
2A
2B
High(G2)
High(G2)
Intracompartmental(T1)
Extracompartmental(T2)
None(M0)
None(M0)
3
Low(G1) or
High(G2)
Intracompartmental(T1)
Or
Extracompartmental(T2)
Yes(M1)

5.  Clinical examination (age, sex, site and past history)
◦ Thyroid
◦ Breasts
◦ Chest
◦ Liver
◦ Kidney
◦ Rectal (prostate & rectal tumours)
 Bloods
◦ FBC (leukaemic cells etc)
◦ ESR (often elevated)
◦ Biochemistry (Ca++, PO4, liver enzymes and Alkaline Phosphatase) -> mets
◦ Acid Phosphatase (prostate and increased with metastatic deposits)
◦ Thyroid function tests
◦ PSA
◦ Serum Protein Electrophoresis (Myeloma)
 Urinalysis
 Urine Bence-Jones (myeloma)
 CXR
 Abdominal ultrasound
 Bone scan -> other sites
 MRI -> soft tissue extent and association with nerves and vessels
 CT of lesion and chest (-> staging)
 Angiography -> tumour blood supply and relationship to major vessels
 Biopsy

6.  Should know probable diagnosis and stage of
tumour before biopsy
 Performed by the surgeon who will perform the
definitive surgery
 Biopsy tract orientation & location is critical - will
need to be included in the definitive surgery if
lesion is malignant.
 Meticulous haemostasis to avoid tracking
haematomas
 Send samples for microbiological analysis

7.  Intra-lesional
◦ through the tumour
◦ leaves macroscopic tumour
◦ not therapeutic
 Marginal
◦ through pseudo-capsule of tumour / reactive zone
◦ controls non-invasive benign tumours
◦ recurrence of malignant tumours = 25-50%
 Wide
◦ around reactive zone, leaving a cuff of normal tissue
◦ skip lesions left
◦ recurrence of malignant tumours = < 10%
 Radical
◦ removal of entire compartment or compartments
◦ distant metastases left
 Amputation
◦ should be thought of as a form of reconstruction where surgical control of
the tumour precludes useful function.

8. Benign Malignant Other
Birth
- 5yr
1. Eosinophilic
Granuloma [onion skin
periosteal Rxn]
2. (Unicameral bone cyst-
rare)
1. laeukaemia
2. Metastatic
Neuroblastoma
1. Osteomyelitis
2. healing/ stress
fracture
6-
18yr
1. Unicameral Bone Cyst
2. Aneurysmal Bone Cyst
3. Nonossifying Fibroma
4. Eosinophilic
Granuloma
5. Enchondroma
6. Chondroblastoma
7. Chondromyxoidfibroma
8. Osteoblastoma
1. Ewings Sarcoma
2. Osteosarcoma
1. Osteomyelitis
2. Fibrous Dysplasia
3. Osteofibrous
Dysplasia
19-
40yr
1. Giant Cell Tumour
2. Eosinophilic granuloma
1. Ewings Sarcoma
40+yr
s
1. Metastases (lung,
breast, prostate,
renal, thyroid,
colon)
2. Multiple Myeloma
3. Lymphoma
4. Osteosarcoma
(Pagets)
5. Chondrosarcoma
6. Fibrosarcoma/
Malignant Fibrous
7. Histiocytoma
1. Hyperparathyroidism
2. Osteomyelitis
3. Paget's

9. Fibroxanthoma
Fibrous cortical defect
Non ossifying fibroma
Fibrosarcoma
Fibrous dysplasia
Round cell lesions
Ewings
Reticulum cell sarcoma
Myeloma
Chondromyxoid fibroma
Chondrosarcoma
Osteoid osteoma
Cortical fibrous dysplasia
Adamantinoma
DIAPHYSISDIAPHYSIS

10. osteosarcoma Enchondroma
Giant cell tumour
osteochondroma
Bone cyst
Osteoblastoma
Chondromyxoid fibroma
Chondrosarcoma
Fibroxanthoma
Fibrous cortical defect
Non ossifying fibroma
METAPHYSISMETAPHYSIS

11. chondroblastoma
Articular osteochondroma
Dysplasia epiphysealis
hemimelica
Giant cell tumour
EPIPHYSISEPIPHYSIS

12.  Fibrous Dysplasia
Osteoblastoma
Giant Cell Tumour
Metastasis/ Myeloma
Aneurysmal Bone Cyst
Chondroblastoma/ Chondromyxoid Fibroma
Hyperparathyroidism (brown tumour)/
Haemangioma
Infection
Non-ossifying Fibroma
Eosinophilic Granuloma/ Enchondroma
Simple Bone Cyst

13.  Vascular
◦ hemangiomas
◦ infarct
 Infection
◦ chronic osteomyelitis
 Neoplasm
◦ primary
 osteoma
 osteosarcoma
◦ metastatic
 prostate
 breast
 other
 Drugs
◦ Vitamin D
◦ fluoride
 Inflammatory/Idiopathic
 Congenital
◦ bone islands
◦ osteopoikilosis
◦ osteopetrosis
◦ pyknodysostosis
 Autoimmune
 Trauma
◦ fracture (stress)
 Endocrine/Metabolic
◦ hyperparathyroidism
 Paget's disease

14.  Pattern of bone destruction
 Tumour matrix
 Cortical expansion/penetration
 Periosteal reaction
 Adjacent soft tissues
 Size & shape of lesion
 Trabeculation
 Growth Plate

15.  Benign lesion - during growth
 20% of benign bone lesions
 Age 5-15 years
 Not found in adults
 Sex m:f 3:1
 The most common location is the proximal humerus
(67%) followed by the proximal femur (15%)
 unusual sites (calcaneum, pelvis) in patients >17 yrs
 Cysts may be Active or Latent: Active cysts are
located near the growth plate, but they move further
away as the child grows and become inactive (latent)

16.  Well defined, central osteolytic area with a thin sclerotic margin
 Metaphyseal in young - moves towards diaphysis with growth
 It fills and slightly expands metaphysis
Pathology
 Thin walled cavities - blood tinged fluid.
 The lining cells are cuboidal,

17.  Treatment goal is to minimise fracture risk until
the cyst heals (but this can take years)
 Steroid injection
◦ 1-3 percutaneous injections repeated at 2 monthly
intervals
◦ 60-80% success rate
 Curettage and bone graft - 50% recurrence
rate and possibility of damage to the growth
plate
 Bone marrow aspirate has recently been used

18. Benign solitary, expansile and erosive lesion of bone
1% of benign bone lesions
Age (85% cases <20 years old)
Sex f:m is 2:1
ABC's can be found in any bone in the body
The most common location is the metaphysis of the lower extremity
long bones, more so than the upper extremity
The vertebral bodies or arches of the spine may be involved
Approximately one-half of lesions in flat bones occur in the pelvis
Presentation
Swelling, tenderness and pain
Limited range of motion due to joint obstruction
Spinal lesions - neurological symptoms
Pathological fractures are rare - eccentric location of the lesion

19.  Placed eccentrically in the metaphysis and appears osteolytic
 The periosteum is elevated; cortex is eroded to a thin margin
 The expansile lesion - "blow-out”
 CT scan -for pelvis or spine lesions
 CT scan can demonstrating multiple fluid-fluid levels
 MRI can also confirm the multiple fluid-fluid levels

20.  A slow growing, indolent ABC has been observed
to regress spontaneously
 Most lesions can be treated with curettage and
application of a high-speed burr
 Recurrence was statistically related to
young age and open growth plates, and may
be less likely following wide excision than
following curettage

21.  Benign, usually solitary and locally aggressive
 10% of benign bone lesions
 malignant transformation (5-10%)
 Not seen until after the growth plate closes
 Rarely metastasises (<1% to lungs)
 Age 20 - 40 years
 More common females
 Most commonly seen in the distal femur,
proximal tibia and the distal radius
 Nearly always located at the very end of a long
bone (metaphyseal / epiphyseal)
 Pathological fracture occurs in 10 - 15%
 Neighbouring joint often irritated (effusion)

22. stagestage clinicalclinical radiologyradiology histologyhistology
II asymptomaticasymptomatic benignbenign benignbenign
IIII symptomaticsymptomatic activeactive benignbenign
IIIIII symptomaticsymptomatic AggressiveAggressive
Mets +Mets +
benignbenign

23.  Usually well defined lesion in
the epiphysis extending up
to the joint surface without
marginal sclerosis, cortex
thinned and sometimes
ballooned
 soap bubble appearance
 Junction with normal bone
poorly defined
 Soft, friable tumour
 Cut surface tan in colour, with
areas of necrosis and
haemorrhage
 Numerous multinucleated giant
cells. The stromal cells are
homogenous mononuclear
round/ovoid with large nuclei
 Up to 50% have soft tissue
extension

24.  Intralesional excision by "extended" curettage
 Curettage alone has a high local recurrence rate (50%) and the
curettage is "extended" into the bone by a few millimetres by
either using a burr, liquid nitrogen or phenol
 The resulting cavity can be filled with bone graft or cement
 En-bloc resection is possible if the bone is expendable e.g.
proximal fibula, proximal radius
 Amputation reserved for massive local recurrence, malignant
change or infection
 Radiotherapy reserved rare cases of unresectable tumours
because of increased risk of secondary malignancy

25.  10% of benign bone tumours
Male : Female 2:1
Peak age 5 - 25 years (85% in this range)
Rare over 40 years
 Location:
Any bone, rarely multifocal
tibia & femur in 50%
spine - posterior elements
Only occurs in bones formed by endochondral ossification
 Clinically
 Pain - commonest presentation
Pain - worse at night and relieved by aspirin
10% occur in the spine
Runs a self limiting course > surgery for pain relief
Pain usually decreases as the lesion matures
Lesion healed by 3 - 7 years

26.  Lytic nidus surrounded by sclerotic bone (which
may mask the nidus)
Centre of nidus may be calcified
CT or tomograms -> diagnosis
Hot spot on bone scan
Differential Diagnosis
 Bone island (enostosis)
 Brodie's abscess
 Osteoblastoma
 fatigue fracture

27.  NSAIDs
◦ relieves symptoms
 Surgical:
◦ Nidus excision -> no recurrence
◦ Intraoperative localisation with:
 Bone scan
 Tetracycline under UV light)
 CT
 X-Ray excised tissue -> contains nidus
 Percutaneous radiofrequency coagulation

28.  Cartilage capped bony projection / exostosis
Commonest benign tumour
Developmental abnormality of the metaphysis
 Accounts for 45% of benign bone tumours
 12% of all bone tumours
 most become evident under 20 years
 May be solitary or multiple (diaphyseal
aclasis)
 Any bone developing by endochondral
ossification may be involved

29.  Autosomal dominant
 Disordered endochondral growth
 Multiple osteochondromas
 Short stature and bowing of limbs
 Treat individual lesions as necessary
and observe for malignant change
 Malignancy Risk = ~ 20%
overall or 0.2% per lesion
 Trevor's Disease:
Osteochondroma on epiphyseal side
of the growth plate

30.  x-ray hallmark is blending of tumour into
underlying metaphysis
 flat, sessile lesion or a peduculated (stalk like) process
 pedunculated osteochondromas are oriented in
proximal direction
 Cartilaginous cap displays irregular areas of
calcification

31.  Nil required unless symptomatic (persistent
irritation (from bursitis or tendon) or neurovascular
compromise)
 Extra capsular marginal excision
◦ Including the cartilaginous cap & overlying perichondrium
◦ Deep bony base has minimal activity & may be removed
piecemeal
◦ The cartilaginous cap should not be traumatised during
removal
◦ Recurrence = < 5%
 Decreased risk of recurrence if excised after
maturity

32.  Risk of malignant change ~ 0.2% in a solitary
lesion
 Risk of malignant change in diaphyseal aclasis
20%
 Sarcomatous change usually ->low grade
 Evidence of transformation to
Chondrosarcoma:
◦ Cartilaginous cap thicker than 1 cm in an adult (in
child may be 2-3 cm thick)
◦ Cartilage cap > 8cm diameter
◦ Fluffy outline
◦ Bone scan - Marked increase in uptake in an adult
◦ CT/MRI - soft tissue mass or displacement of a
major neurovascular bundle

33.  10% of benign bone tumours
 50% occur in small bones of the hands and feet
 15% femur and 12% humerus
 Peak incidence 10 - 50 years
 May be solitary or multiple (Olliers, Mafuccis)
 Clinically
 Usually metaphyseal
 75% Solitary
 60% present as fractures
 pathological fracture, lump
 incidental finding

34.  X-Rays Scalloped erosions on endosteal
surface
 flecks of calcification - sometimes called 'ground
glass'
enchondroma (typical appearance & site)

35.  Macroscopically - bluish white well
demarcated
 hypocellular; nests of mature
cartilage cells,
 Ollier's disease - more cellular;
50% ->malignant transformation
 Mafucci's disease - associated
with multiple haemangiomata
and associated with nearly 100%
malignant change somewhere

36.  Observe - x-ray 6 months & 1 year after
presentation
 Curettage and grafting if latent
 Recurrence - en block excision

Prognosis
 Risk of malignant change in Olliers is 50%
 malignant change in Mafuccis is nearly 100%

37.  5 - 20% benign bone lesions
 usually monostotic
 Affects children and adolescents
 Median age at onset 8 years
 Male > Female (Albrights - Female > Male)
 McCune - Albrights Syndrome
 Polyostotic disease (unilateral usually)
 Skin pigmentation
◦ cafe au lait spots with serrated borders (called "coast of Maine") that tend to stop
abruptly at the midline of the body
 Precocious puberty (endocrinopathy)
 usually presents earlier, may be unilateral or widespread, affecting long
bones, hands, feet & pelvis
 Malignant transformation (chondrosarcoma or osteosarcoma) is about 4 %;

38.  Lucent lesion in medullary space
 Sclerotic margin.
 Ground glass appearance
 No periosteal reaction
 Shepherds crook - proximal femur
 expansion of cortex
 Pathology
 Bone replaced by firm, whitish tissue of
gritty consistency
 bone trabeculae separated by fibrous
tissue.
 Bone is woven rather than lamellar

39.  Pagets disease
 FCD
 Hyperparathyroidism
 osteoblastoma
 osteosarcoma
 Treatment
 Monostotic -> curettage and grafting if symptomatic
 Polyostotic -> symptomatic treatment
 May require osteotomy for deformity or lengthening / shortening procedures
 Prognosis
 Monostotic lesions cease activity at puberty but may be reactivated by
pregnancy
 Polyostotic - 85% -> pathological fracture
 malignant change occurs after radiotherapy