Benign MSK tumours

Question 1

What is a benign tumour of fat cells known as?

Answer 1

Lipoma

Question 2

What is a benign tumour of blood vessels known as?

Answer 2

Haemangioma

Question 3

What is a benign tumour of smooth muscle known as?

Answer 3

Leiomyoma

Question 4

What is a benign tumour of skeletal or cardiac muscle known as?

Answer 4

Rhabdomyoma

Question 5

What is a benign tumour of cartilage known as?

Answer 5

Chondroma

Question 6

What is a benign tumour of bone known as?

Answer 6

Osteoma

Question 7

What are some benign, superficial tumours that do cause pain (most don’t)?

Answer 7

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)

Question 8

What are lipomas?

Answer 8

Lipomas are benign tumours of fat cells and are the most common soft tissue tumour

Question 9

Where can lipomas be found?

Answer 9

They usually occur in the subcutaneous fat, however, they can occur in muscle

Question 10

What are some types of lipoma?

Answer 10

• Simple
• Intramuscular
• Fibrolipoma
• Angiolipoma
• Splindle cell lipoma - Usually on neck
• Pleomorphic lipoma - Usually on neck
• Atypical lipoma - Superficial

Question 11

What are some features suggestive of a lipoma?

Answer 11

• 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

Question 12

How are lipomas usually managed?

Answer 12

Management is based on symptoms and can either be left alone, or surgically excised if causing symptoms

Question 13

Where do leiomyomas most commonly affect?

Answer 13

Uterine fibroid lining

Question 14

What are some MSK locations of leiomyomas?

Answer 14

Erector pilae
Deeper soft tissues and muscularis of the GI tract

Question 15

Describe the histology of leiomyomas

Answer 15

Histologically, they will show fascicles of spindle cells, cigar shaped nuclei and few mitoses
Usually 1-2cm in diameter

Question 16

What will be shown on immunohistochemistry in leiomyomas?

Answer 16

Actin
Desmin
Caldesmon

Question 17

What are enchondromas?

Answer 17

These are intramedullary and usually metaphyseal cartilaginous tumours, caused by failure of normal enchondral ossification at the growth plate

Question 18

Who is most at risk of enchondroma?

Answer 18

Ages 20-50
Those will Ollier’s and Maffuci syndrome

Question 19

How do enchondromas usually present?

Answer 19

Many are incidentally found and are usually asymptomatic, however, they can weaken bone, leading to pathological fracture

Question 20

What are the most commonly affected bones by enchondroma?

Answer 20

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

Question 21

What will X-ray show in enchondroma?

Answer 21

A lucent lesion on imaging, with possible patchy sclerotic appearance

Question 22

How are enchondromas managed?

Answer 22

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

Question 23

What is an osteochondroma?

Answer 23

These are benign lesions derived from aberrant cartilage from the perichondral ring

These are the most common benign bone tumours

Question 24

Who are osteochonrdomas common in?

Answer 24

They are common in adolescents and young adults (10-20 years)

Question 25

What are some possible causes of osteochondroma?

Answer 25

Trauma Multiple Hereditary Exostosis

Question 26

Describe the pathology of an osteochondroma

Answer 26

Osteochondromas produce a bone outgrowth on the external surface with a cartilaginous cap

Question 27

How may osteochondromas present?

Answer 27

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

Question 28

What investigation is required in osteochondroma?

Answer 28

X-ray

Question 29

What will X-ray show in osteochondroma?

Answer 29

Cartilage capped ossified pedicle

Question 30

How are osteochondromas managed?

Answer 30

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

Question 31

Why is risk of malignant transformation increased in MHE?

Answer 31

There are more tumours

Question 32

What are chondromyxoid fibromas>

Answer 32

Chondromyxoid fibromas are tumours of the articular cartilage

Question 33

Describe the histology of chondromyxoid fibromas

Answer 33

The are characterised by variable amounts of chondroid, fibromatoid and myxoid elements

Question 34

Who is most at risk of developing chondromyxoid fibromas?

Answer 34

Older children and young adults

Question 35

To what age group os cardiac rhabdomyoma limited to?

Answer 35

Paediatric age group

Question 36

What are some complications of cardiac rhabdomyoma?

Answer 36

Valvular obstruction Occupation of cardiac chambers

Question 37

Where can rhabdymyomas form outside of the heart?

Answer 37

Head and neck in older patients

Question 38

What are the main causes of rhabdomyomas?

Answer 38

50% of cases are caused by sporadic mutations 50% are associated with tuberose sclerosis and mutations of TSC1 and 2

Question 39

What bones are most commonly affected by osteomas?

Answer 39

Cranial bones

Question 40

What condition can lead to multiple osteoma formation?

Answer 40

Gardener's syndrome

Question 41

What are osteoid osteomas?

Answer 41

These are benign bone-forming tumours

Question 42

Who is most at risk of developing osteoid osteomas?

Answer 42

Adolescents Males

Question 43

What bones are most commonly affected by osteoid osteomas?

Answer 43

Appendicular skeleton, most commonly femur and tibia

Question 44

What region of bone is most commonly affected by osteoid osteoma?

Answer 44

Cortex

Question 45

Describe the histology of osteoid osteoma

Answer 45

Osteoid bone and tumour cells form the nidus (Nest) of the tumour, with reactive bone surrounding it

Question 46

How will osteoid osteomas present?

Answer 46

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

Question 47

What are some investigations that can be used in osteoid osteoma?

Answer 47

X-ray Bone scans CT

Question 48

What will CT show in osteoid osteoma?

Answer 48

CT will show a small nidus of immature bone, surrounded by an intense sclerotic halo (Osteoblastic rim)

Question 49

How are osteoid osteomas managed?

Answer 49

The lesion may resolve spontaneously over time, however, some cases may require CT guided radio-frequency ablation or en bloc excision

Question 50

What are osteoblastomas?

Answer 50

These are larger tumours of bone, which involve the vertebrae posterorly

Question 51

How do osteoblastomas differ from osteoid osteoma in presentation?

Answer 51

Pain will not be responsive to aspirin