Osteosarcoma

Question 1

Incidence

Answer 1

• Rare, highly malignant
• Most common 1ary malignancy
• Primarily childhood / adolescence
• Occur later in life 2ary to Pagets Dz

Question 2

Definition & Dx

Answer 2

A highly malignant osteoid producing tumour comprised of primitive osteoblasts

Dx based on histological examination

Question 3

Distribution

Answer 3

• may affect any bone
• typically affects long bone metaphysis
• around knee
• proximal humerus

Question 4

Clinical Picture (Pain / Lump / Swelling)

Answer 4

• pain as first SSx
• constant
• worse at night
• incr. in severity
• Pt may present with lump / swelling
• Examination
• tenderness / swelling
• palpable mass
• surround ST inflamed / swollen

Question 5

Lab Investigations

Answer 5

• Incr. ESR (systemic inflammation)

* Incr ALP (bone destruction)

Question 6

Radiol Fx

Answer 6

 variable
 hazy, osteolytic areas in metaphysis
 dense osteoblastic areas
 poor definition of endosteal margin
 breaching of cortex:
 the tumour extends into adjacent tissue
 streaks of new bone extend outwards from cortex
 sunburst / sunray effect
 reactive new bone formation at angles of periosteal elevation (“Codman’s triangle”)
 neither sunburst / Codman’s triangle are pathognomonic
 pulmonary metastases

Question 7

Treatment

Answer 7

• surgical / amputation

- adjunct chemo (80% LT survival)

Question 8

Pathology

Answer 8

• Osteosarcoma destroys and replaces bone
• Observe alternating areas of;
o Bone loss
o Abnormal new bone production (especially at periosteal margins secondary to periosteal lifting)
• Quickly spreads outwards