Soft Tissue Tumours Flashcards
What is meant by a soft tissue tumour?
What structures tend to be implicated?
a tumour of non-bony mesenchymal structures
can involve connective tissue, muscle, fat and blood vessels
What are the 2 types of soft tissue tumours?
What age groups tend to be affected?
benign tumours are common
malignant tumours are rare
they occur in all age groups
What inherited conditions can predispose people to getting soft tissue tumours?
- Gardeners
- Li-Fraumeni syndrome
- neurofibromatosis
What viruses can predispose people to developing soft tissue tumours?
- HHV8 predisposes to kaposi’s sarcoma
- Epstein-Barr virus predisposes to smooth muscle tumours
How can radiotheraphy affect development of soft tissue tumours?
it can lead to angiosarcoma development, usually 10 years after treatment
What are the most common sites for malignant soft tissue tumours?
The thigh and retroperitoneum
soft tissue tumours can occur at any site in the body
What are the stages in medical management of soft tissue tumours?
- history
- examination
- radiology
- biopsy
- stage
- MDT
- treat and follow up
What is the common presentation of a soft tissue tumour?
most patients present with a lump
lumps are very common, but sarcomas are rare
What are the clinical clues that a ‘lump’ may be something more sinister?
- painful
- deep to deep fascia (not subcutaneous)
- > 5 cm in size
- recurrent
- enlarging
What are the radiological clues that a lump may be something more sinister?
- > 5cm
- deep to deep fascia
- heterogenous appearance
What is the only way to determine whether a soft tissue tumour is malignant or benign?
By taking a biopsy
What are the typical endings for a benign and malignant tumour?
benign - “oma”
malignant - “sarcoma”
What are the general names for the following tumours?
What are the 3 main problems with classifying soft tissue tumours?
- outdated names - synovial sarcoma is not actually in the synovium
- some have no normal tissue counterpart so can only be identified by patterns down the microscope
- some are named after the person who discovered them
What are the 3 things that might be carried out on a biopsy?
- histopathology (looking down a microscope)
this involves immunohistochemistry
- cytogenetics to look for chromosomal abnormalities
- molecular pathology
What is the purpose of immunohistochemistry?
it involves looking for certain proteins in cells to determine which cell type is present
What are the pitfalls when making a differential diagnosis of a soft tissue tumour biopsy?
- it could be lymphoma/leukaemia
- metastases - especially melanoma but also carcinoma and germ cell tumour
- reactive pseudotumour
What is shown here?
lipoma
What is shown here?
liposarcoma
mature fat globules are visible within the tumour
What is shown here?
leiomyoma
this looks like normal smooth muscle cells
What is shown here?
leiomyosarcoma
necrosis is present
What is shown here?
small round blue cell tumour
What is the differential diagnosis of a small round blue cell tumour?
sarcoma:
- Ewing’s sarcoma
- neuroblastoma
- rhabdomyosarcoma
carcinoma:
- small cell carcinoma e.g. lung
germ cell tumour:
- embryonal carcinoma
lymphoma
What is shown here?
How can it be identified by immunohistochemistry?
rhabdomyosarcoma
an antibody to desmin is used, which is a part of muscle
What are the 4 main features of a malignant soft tissue tumour?
- metastases
- necrosis
- mitoses - abnormal numbers or atypical forms
- cytological aytipia (variations in size and shape of the nucleus)
What feature of malignancy is shown?
abnormal mitoses
What feature of malignancy is shown?
tumour necrosis
What are 2 self limiting lesions that may stimulate sarcoma?
- nodular fasciitis
- myositis ossificans
What is myositis ossificans?
it occurs in young adults
it is a rapidly growing lump on the limb that is often mistaken for sarcoma
How do soft tissue tumours tend to be classified?
many soft tissue tumours have characteristic chromosomal changes
cytogenetics and molecular biology can be used to look for chromosome abnormality, fusion RNA or protein expression
What is the prognosis for a sarcoma?
50% of sarcoma patients are alive at 5 years
What are the 3 treatment options for sarcomas?
- surgery by radical excision - this is the main treatment option
- radiotherapy
- chemotherapy
Where do soft tissue sarcomas tend to spread to?
The lungs are the first place that the cancer will spread to
Rarely it spreads to the lymph nodes
What is the post-operative pathology involved in sarcoma treatment?
- confirm the diagnosis
- grade using the FNCLCC system (1-3)
- look for the margins of the sarcoma
Why may radiotherapy be used preoperatively?
- to downstage the size and extent of the tumour
the tumour may be too large or encompassing too many vital structures
shrinking it makes it operable
Why may adjuvant radiotherapy be used post-operatively?
to prevent local recurrence
What are the 3 main complications associated with adjuvant radiotherapy?
- fibrosis
- fracture to the underlying bone
- radiation induced tumours (these are usually sarcomas)
When is adjuvant chemotherapy used in addition to surgery?
- pre-surgery to shrink the tumour
- in systemic disease when the cancer has spread
- paediatric sarcomas
- in GIST
Why is chemotherapy often used in paediatric sarcomas?
small blue cell tumours are chemoresponsive
this means there is no need for surgery
What is the typical treatment for gastrointestinal stromal tumours (GIST)?
Imatinib
this is a synthetic tyrosine kinase inhibitor
What is GIST?
What causes it?
it is a tumour of modified smooth muscle of bowel wall
most cells have a cell membrane receptor CD11 (tyrosine kinase receptor)
this controls cell proliferation and differentiation and is constantly turned on in the tumor
