Sarcomas

Question 1

Name the bone sarcomas

Answer 1

Osteosarcoma, Ewings sarcoma, chondrosarcoma (originate from chondrocytes)

Question 2

Soft tissue sarcoma

Answer 2

Liposarcoma - adipocytes
Rhabdomyosarcoma - striated muscle
Leiomyosarcoma - smooth muscle
Synovial sarcomas - close to joints
Malignant fibrous histiocytoma is a sarcoma that can arise both in bone and soft tissue

Question 3

What are the features that should make one suspect sarcoma?

Answer 3

Large >5cm soft tissue mass
Deep tissue location or intra muscular location
Rapid growth
Painful lump

Question 4

How would one assess a sarcoma?

Answer 4

MRI, CT and USS. In children first line for unexplained bony mass with suspicion of sarcoma is an xray within 48 hours. No blind biopsy and such that tract can be removed with resection

Question 5

Ewings sarcoma

Answer 5

males>females, onset typically between 10 and 20. Location typically femoral diaphysis. Histology shows a small round tumour. Blood borne mets with chemo and surgery required

Question 6

osteosarcoma

Answer 6

Mesenchymal cells with osteoblastic differentiation
20% of all primary bone tumours
Incidence of 5 per 1,000,000
Peak age 15-30, commoner in males
Limb preserving surgery may be possible and many patients will receive chemotherapy

Question 7

Liposarcoma

Answer 7

Malignancy of adipocytes
Rare, approximately 2.5 per 1,000,000. They are the second most common soft tissue sarcoma
Typically located in deep locations such as retroperitoneum
Affect older age group usually >40 years of age
May be well differentiated and thus slow growing although may undergo de-differentiation and disease progression
Many tumours will have a pseudocapsule that can misleadingly allow surgeons to feel that they can ‘shell out’ these lesions. In reality, tumour may invade at the edge of the pseudocapsule and result in local recurrence if this strategy is adopted
Usually resistant to radiotherapy, although this is often used in a palliative setting

Question 8

Malignant Fibrous Histiocytoma

Answer 8

Tumour with large number of histiocytes
Most common sarcoma in adults
Also described as undifferentiated pleomorphic sarcoma NOS (i.e. Cell of origin is not known)
Four major subtypes are recognised: storiform-pleomorphic (70% cases), myxoid (less aggressive), giant cell and inflammatory
Treatment is usually with surgical resection and adjuvant radiotherapy as this reduces the likelihood of local recurrence