In terms of soft tissue swellings, what are the key features to evaluate on examination?
- Definition (well or ill-defined)
- Consistency (cystic, soft or hard)
- Surface smooth or regular
- Mobile or fixed
- Temperature (checks for abscesses)
- Transilluminable (fluid filled)
- Overlying skin changes
- Local lymphadenopathy
What are the features that are suggestive of a benign neoplasm?
- Smaller size (<5cm)
- Fluctuation in size
- Cystic lesions
- Well-defined lesions
- Fluid filled lesions
- Soft/fatty lesions
What are the features suggestive of a malignant neoplasm in soft tissue?
- Larger lesions (>5cm)
- Rapid growth size
- Solid lesions
- Ill-defined lesions
- Irregular surface
- Associated lymphadenopathy
- Systemic upset
- Deep location
- Gadolinium enhancement (moreso than non-maligant tissues)
What types of systemic upset are common in malignant soft tissue lesions?
- Weight loss
- Loss of appetite
Why is a history of an extremely rapidly growing (one week) soft tissue lesion reassuring?
This is much more associated with reactive pseudotumour formation rather than malignancy
If there is doubt about the diagnosus of a certain swelling, what is the next step?
Imaging via MRI
Biopsy for histological diagnosis
What is the most common benign soft tissue lesion
a) In general
b) In orthopaedic practice
a) Leiomyoma (occur as fibroids in the uterus)
Where does a lipoma occur?
Rarely in muscle
Describe the common features of a subcutaneous lipoma
- May not be particularly well defined
What is a giant cell tumour of a tendon sheath?
A small firm swelling arising from a synovial tendon sheath or joint most commonly found on the flexor tendon sheath of a finger
It is the second most common hand swelling after ganglions
How does a giant cell tumour present histologically?
- Pigmented lesion
- Multinucleated giant cells
- Haemosiderin is present (iron storage complex gives brown appearance)
As well as the flexor tendon sheath of a finger, where else are giant cell tumours common and what are they called when present here?
Pigmented villonodular synovitis (PVNS)
How can giant cell tumours be treated?
- Excision (high recurrence rate)
What is the potential danger of leaving a pigmented villonodular synovitis in a joint such as the knee?
It may lead to joint destruction and arthritis
This may require synovectomy or total knee replacement
Angiosarcomas occur in which age groups?
Angiosarcomas are the most common sarcoma to occur after what?
Which sarcomas often have a very unclear origin and what are they known as when extremely poorly differentiated?
Pleomorphic undifferentiated sarcoma
Where do liposarcomas most commonly manifest and why can they rarely be a cause of scrotal swelling?
Deep fatty tissues in the abdomen
(almost NEVER subcutaneous fat)
The testes have their embryological origin in the abdomen so similar tissue is present around them compared with the abdomen which is also more susceptible to liposarcomas
What is the name of a malignant tumour of skeletal muscle?
Which tumours have an unknown origin, most commonly manifest around the knee joint and commonly present with calcification on X-ray?
Synovial sarcoma is a bi-phasic tumour, what does this mean?
It contains both sarcomatous elements and epithelial elements
Synovial sarcomas are associated with which genetic defect?
Recurrent translocation (tX;18)
In what age bracket do sarcomas most commonly present?
What is the standard treatment for sarcomas once they have been identified?
Surgery with adjunctive chemo/radiotherpay
(surgery involves radical (removal or surrounding structures e.g. blood supply, lymph nodes etc.) or wide local excision)
What is the most common hand swelling?
Why does a ganglion cyst develop?
Herniation of synovial fluid at a weak point in a joint capsule or tendon sheath
This weakness can be developmental or as a result of underlying joint damage
Ganglion cysts are usually due to underlying ________________
Describe what a ganglion cyst is
A lesion comprised of an outpouching of synovial fluid with a fibrous outer lining with an inner synovial lining that commonly occurs around a synovial joint or synovial tendon sheath
They tend to be well defined, quite firm and transilluminate
Where do ganglion cycts usually occur?
DIP joints, foot, ankle, knee, wrist
What are the treatment options for a ganglion cyst?
- Aspiration (50% recurrence)
What is the term given to a ganglion cyst occuring at a DIP joint?
Why are ganglion cysts not true cysts?
They are not lines by epithelium and instead just by a fibrous outerlining
What is a Baker's cyst?
A lesion caused due to an outpouching of synovial fluid in the popliteal fossa
A one-way valve is created to the semimembranosus or medial gastrocnemius bursa causing this build up
In adults Baker's cysts are usually as a result of what?
Why are Baker's cysts generally not excised?
They have a high recurrence rate
Generally they go away on their own
What is a bursa and what is its purpose?
A small fluid-filled sac lined by synovium that occurs around a joint that serve to prevent friction between bones, tendons, muscles and surrounding skin
What are the most common bursae to become inflamed?
- Pre-patellar bursa
- Olecranon bursa
- 1st metatsarsal bursa
What is the term given to a bursa present at the 1st metatarsal head?
(this usually occurs as a result of hallux valgus)
What are the main causes of bursitis?
- Repeated trauma or pressure
With which cause of bursitis is recurrence most likely?
Excision may be required
By which other name are sebaceous cysts known?
Epidermal inclusion cysts
Sebaceous cysts are not _________ and __________ increase in size
Sebaceous cysts are not painful and slowly increase in size
How are sebaceous cysts characterised?
Being lined by squamous epithelium which produces abdundant keratin
(when ruptured, this degenerate keratin is released as a toothpaste like substance)
What is an implantation dermoid?
A soft tissue swelling caused by penetrating trauma which forces epithelial cells into subcutaneous tissue
This forms a reactive cyst surrounded by a pseudocapsule
What is the purpose of the punctum in the centre of a sebaceous (epidermoid) cyst?
Tethers the cyst to epidermis
Where are sebaceous cysts not found?
Palms and soles
What does an abscess consist of?
- Infective debris
- Cellular debris
- Infective organism
Why may abscesses form?
- Infected wound
- Epidermoid cyst
- Blocked sweat gland
- Injection site
Why are antibiotics not useful in treating bursitis and what is the preferred treatment?
Antiobiotics cannot penetrate into the abscess (it does not have a blood supply)
Incision and drainage
What is heterotopic ossification?
The presence of bone in soft tissue where it is not normally found
This can be seen after hip replacement, blunt trauma, due to osteophytes or osteoclast activity
What is the treatment for herterotopic ossificans?
- Excision when mature (12 months)
- Radiotherapy post op
What is a common confusion for intramuscular haematoma?
How can intramuscular haematoma be treated?
What are pseudotumours?
Tumours which mimic neoplasms, but are just reactive/inflammatory lesions
Myositis ossificans and nodular fasciitis are examples of what?
What is myositis ossificans?
Progressive ossification at an injury site for unknown reasons
Where are ganglion cysts generally found?
Adjacent to a tendon or synovial joint
Giant cell tumours of the tendon sheath generally occur on the __________ surface especially around the ___ _______ of the _________ and __________ fingers
Giant cell tumours of the tendon sheath generally occur on the palmar surface especially around the PIP joints of the index and middle fingers
Why is excision usuall recommended for giant cell tumours of the tendon sheath?
It prevents local spread and deals with symptoms