Benign MSK tumours Flashcards
What is a benign tumour of fat cells known as?
Lipoma
What is a benign tumour of blood vessels known as?
Haemangioma
What is a benign tumour of smooth muscle known as?
Leiomyoma
What is a benign tumour of skeletal or cardiac muscle known as?
Rhabdomyoma
What is a benign tumour of cartilage known as?
Chondroma
What is a benign tumour of bone known as?
Osteoma
What are some benign, superficial tumours that do cause pain (most don’t)?
These are known as the ANGEL tumours:
- A - Angiolipoma
- N - Neuroma (Traumatic)
- G - Glomus tumour (Nail beds)
- E - Eccrine spiradenoma (Skin adnexal tumour)
- L - cutaneous Leiomyoma (Of erector pilae)
What are lipomas?
Lipomas are benign tumours of fat cells and are the most common soft tissue tumour
Where can lipomas be found?
They usually occur in the subcutaneous fat, however, they can occur in muscle
What are some types of lipoma?
- Simple
- Intramuscular
- Fibrolipoma
- Angiolipoma
- Splindle cell lipoma - Usually on neck
- Pleomorphic lipoma - Usually on neck
- Atypical lipoma - Superficial
What are some features suggestive of a lipoma?
- Smaller size
- Fluctuations in size (Malignant tumorus don’t regress)
- Cystic lesions
- Well-defined lesions
- Fluid filled lesions
- Soft/fatty lesion
- Painless and non-tender
- No overlying skin changes
How are lipomas usually managed?
Management is based on symptoms and can either be left alone, or surgically excised if causing symptoms
Where do leiomyomas most commonly affect?
Uterine fibroid lining
What are some MSK locations of leiomyomas?
Erector pilae
Deeper soft tissues and muscularis of the GI tract
Describe the histology of leiomyomas
Histologically, they will show fascicles of spindle cells, cigar shaped nuclei and few mitoses
Usually 1-2cm in diameter
What will be shown on immunohistochemistry in leiomyomas?
Actin
Desmin
Caldesmon
What are enchondromas?
These are intramedullary and usually metaphyseal cartilaginous tumours, caused by failure of normal enchondral ossification at the growth plate
Who is most at risk of enchondroma?
Ages 20-50
Those will Ollier’s and Maffuci syndrome
How do enchondromas usually present?
Many are incidentally found and are usually asymptomatic, however, they can weaken bone, leading to pathological fracture
What are the most commonly affected bones by enchondroma?
Small bones of the hands and feet, however, they can also affect the femur, humerus and tibia
Lesions in the digits are almost never malignant
What will X-ray show in enchondroma?
A lucent lesion on imaging, with possible patchy sclerotic appearance
How are enchondromas managed?
Once a fracture has healed, or if there is a risk of impending fracture, they may be scraped out (Curettage) and filled with bone graft to strengthen the bone
What is an osteochondroma?
These are benign lesions derived from aberrant cartilage from the perichondral ring
These are the most common benign bone tumours
Who are osteochonrdomas common in?
They are common in adolescents and young adults (10-20 years)
What are some possible causes of osteochondroma?
Trauma
Multiple Hereditary Exostosis
Describe the pathology of an osteochondroma
Osteochondromas produce a bone outgrowth on the external surface with a cartilaginous cap
How may osteochondromas present?
as a painless, hard lump, commonly near the knee at the distal femur or proximal tibia
There may be some symptoms with activity, such as pain from tendons or numbness from nerve compression
What investigation is required in osteochondroma?
X-ray
What will X-ray show in osteochondroma?
Cartilage capped ossified pedicle
How are osteochondromas managed?
Close observation, as there is a small risk of malignant transformation (<1%) so any lesion that grows in size or causes pain may require excision
Why is risk of malignant transformation increased in MHE?
There are more tumours
What are chondromyxoid fibromas>
Chondromyxoid fibromas are tumours of the articular cartilage
Describe the histology of chondromyxoid fibromas
The are characterised by variable amounts of chondroid, fibromatoid and myxoid elements
Who is most at risk of developing chondromyxoid fibromas?
Older children and young adults
To what age group os cardiac rhabdomyoma limited to?
Paediatric age group
What are some complications of cardiac rhabdomyoma?
Valvular obstruction
Occupation of cardiac chambers
Where can rhabdymyomas form outside of the heart?
Head and neck in older patients
What are the main causes of rhabdomyomas?
50% of cases are caused by sporadic mutations
50% are associated with tuberose sclerosis and mutations of TSC1 and 2
What bones are most commonly affected by osteomas?
Cranial bones
What condition can lead to multiple osteoma formation?
Gardener’s syndrome
What are osteoid osteomas?
These are benign bone-forming tumours
Who is most at risk of developing osteoid osteomas?
Adolescents
Males
What bones are most commonly affected by osteoid osteomas?
Appendicular skeleton, most commonly femur and tibia
What region of bone is most commonly affected by osteoid osteoma?
Cortex
Describe the histology of osteoid osteoma
Osteoid bone and tumour cells form the nidus (Nest) of the tumour, with reactive bone surrounding it
How will osteoid osteomas present?
These are lesions of less than 2cm
They cause intense constant pain, worse at night due to the intense inflammatory response
Pain is greatly relieved by NSAIDs or aspirin
What are some investigations that can be used in osteoid osteoma?
X-ray
Bone scans
CT
What will CT show in osteoid osteoma?
CT will show a small nidus of immature bone, surrounded by an intense sclerotic halo (Osteoblastic rim)
How are osteoid osteomas managed?
The lesion may resolve spontaneously over time, however, some cases may require CT guided radio-frequency ablation or en bloc excision
What are osteoblastomas?
These are larger tumours of bone, which involve the vertebrae posterorly
How do osteoblastomas differ from osteoid osteoma in presentation?
Pain will not be responsive to aspirin
