MSK Swellings

Question 1

what investigation can be used to differentiate solid adn cystic swelling

Answer 1

US

Question 2

benign features

Answer 2

• Smaller size (<5cm)
• Fluctation in size
• Cystic / fluid filled
• Well defined
• Soft / fatty

Question 3

malignant features

Answer 3

• >5cm
• Rapid growing
• Solid
• Ill defined
• Irregular surface
• Systemic upset
• Lymphadenopathy

Question 4

use of MRI - benign and malignancy

Answer 4

• better anatomical definition
• good at identifying benign features
• has poorer histological correlation with more aggressive features but can identify aggressive or worrying features and indicate the need for biopsy

Question 5

leiomyoma

Answer 5

smooth muscle benign tumour

Question 6

what is the most common type of benign soft tissue tumour

Answer 6

leiomyoma - occur as fibroids in the uterus

Question 7

what is the most common benign tumour in terms of orthopaedic practice

Answer 7

lipoma, usually occuring in subcutaenous fat but can occur in muscle

Question 8

sarcomA

Answer 8

Malignant soft tissue tumour arising from connective tissue

Question 9

what is the most common sarcoma to occur as a result of radiotherapy

Answer 9

angiosarcoma - breast is often involved

Question 10

fibrosarcoma

Answer 10

very rare tumour, of unclear origin

Question 11

what is a poorly differentiated sarcoma referred to as

Answer 11

• Pleomorphic Undifferentiated Sarcoma (PUS)

Question 12

which type of fat does liposarcoma occur in

Answer 12

deep fatty tissues (most often in the abdomen), almost never in subcutaenous fat

Question 13

what can liposarcomas cause in the testis

Answer 13

scrotal swelling - testes descend embryologically from the abdomen and there for the fat at this site embryologically has an origin from the retroperitoneum where these tumours are more common.

Question 14

rhabdomyosarcoma

Answer 14

malignant tumour of skeletal muscle

Question 15

management of sarcoma

Answer 15

• if nature of lesion is indeterminate on clinical assessment and MRI, perform biopsy and can refer
• grade and stage cancer
• treatment is usually surgical with adjunctive chemo ± radio

Question 16

management of bursitis

Answer 16

arthroscopic bursectomy - removal

Question 17

implantation dermoid

Answer 17

• implantation of epidermal cells into dermis by a penetrating injury
• The epidermis continues to grow and forms a cyst lined by stratified squamous epithelium and filled with keratin
• Typically, a grayish fluid

Question 18

epidermoid (sebaceous) cyst

Answer 18

• common
• Epidermal cells find their way into subcutaneous tissue and create a cyst that produces keratin
• When they rupture they produce a cheesy substance that consists of degenerate keratin
• Often have a punctum that tethers the cyst to the epidermis.

Question 19

where can epidermal cysts arise

Answer 19

anywhere except soles of feet and palms

Question 20

myositis ossificans

Answer 20

• formation of bone tissue inside muscle tissue after traumatic injury to the area
• this is known as heterotopic ossification (presence of bone in soft tissue where it does not normally exist)

Question 21

what may myositis ossificans mimic

Answer 21

pseudotumour - may mimic neoplasm

Question 22

what injuries does myositis ossificans often occur after

Answer 22

• injury can be innocuous
• can form after muscle contusion
• fractures - especially elbow
• dislocations - especially traumatic hip dislocation

Question 23

management of myositis ossificans

Answer 23

• physio can result in more ectopic bone formation - avoid
• excise abnormal bone once swelling and new bone formation has settled

Question 24

clinical features of myositis ossificans

Answer 24

usually painless and diminshes over time

Question 25

pharmacological management of myositis ossificans

Answer 25

indomethacin (high strength NSAID) can help with progression