Pathology of MSK Tumours II

Question 1

What are some features of soft tissue tumours?

Answer 1

May present as lump or swelling, may be associated with pain or discomfort, superficial lesions less likely to be malignant

Question 2

What are some examples of soft tissue tumours?

Answer 2

Ganglion cysts, rheumatoid nodules, gouty tophus, tenosynovitis, proliferative conditions, benign tumours, malignancy

Question 3

What are some features of nodular fasciitis?

Answer 3

Self-limiting, cellular proliferation of fibroblastic and myofibroblastic cells, upper age limit of young adults, rapidly growing tumour

Question 4

How does nodular fasciitis appear?

Answer 4

Superficial or deep, usually less than 5cm, circumscribed, very cellular, plump cells, stellate and spindle, cells mature towards periphery

Question 5

What are some features of myositis ossificans?

Answer 5

Associated with insertions of large muscles of arms and legs, cellular proliferation but with evidence of bone formation and zonation

Question 6

How does Dupuytren’s contracture appear?

Answer 6

Firm grey-white tissue, nodules and fascicles, bland fibroblasts and dense collagen

Question 7

What are some features of deep fibromatosis?

Answer 7

Desmoid tumour, large infiltrative masses, don’t metastasise, commonly teens-age 30, associated with mutation of APC and beta-catenin genes

Question 8

What are some common sites of deep fibromatosis?

Answer 8

Limb girdles, mesenteric tissue, musculo-aponeurotic tissue of abdominal walls

Question 9

What are some examples of tenosynovitis?

Answer 9

Giant cell tumours of tendon sheath = digits and wrist, excise and rarely recur
Pigmented villonodular synovitis = large joints, likely to recur

Question 10

What are some classes of lipomas?

Answer 10

Simple lipoma, intramuscular lipoma, fibrolipoma, angiolipoma (spindle cell, pleomorphic, atypical)

Question 11

Where do lipomas occur?

Answer 11

Usually on neck, must be superficial

Question 12

What are some features of liposarcomas?

Answer 12

One of most common sarcomas, patients aged 50-60, deep soft tissue of extremities or retroperitoneum, subtypes (well differentiated, myxoid, pleomorphic)

Question 13

What measures are used to grade sarcomas?

Answer 13

Degree of differentiation
Degree of proliferation:mitotic count
Presence of coagulative necrosis

Question 14

What are some examples of leiomyomas?

Answer 14

Uterine (fibroid), leiomyoma of erector pilae or rarely in deeper soft tissues/muscularis of GI tract

Question 15

How do leiomyomas appear?

Answer 15

Soft tissue leiomyomas usually 1-2cm, fascicles of spindle cells, cigar shaped nuclei, minimal atypia and few mitoses

Question 16

What are some features of leiosarcomas?

Answer 16

More common in females, deep soft tissue of extremities and retroperitoneum, recur if exclusion not complete, lethal due to local invasion and metastasis

Question 17

What are some examples of benign cartilaginous tumours?

Answer 17

Enchondroma = digits, can be part of syndrome (Ollier’s and Maffuci)
Osteochondroma
Chondromyxoid fibroma

Question 18

What do chondrosarcomas produce?

Answer 18

Cartilage

Question 19

What are some types of chondrosarcomas?

Answer 19

Conventional (90%) = intramedullary or juxtacortical

Clear cell, mesenchymal, dedifferentiated

Question 20

Who gets chondrosarcomas?

Answer 20

More common in adults >40

Clear cell and mesenchymal affect younger patients

Question 21

Where do chondrosarcomas occur?

Answer 21

Axial skeleton, head and neck

Clear cell arises in epiphyses of long bones

Question 22

What are some characteristics of chondrosarcomas?

Answer 22

Bulky tumours, nodules of grey/white tissue, locally invasive in bone and into muscle and fat

Question 23

How are chondrosarcomas graded?

Answer 23

Grade 1-3
Lost conventional tumours are grade 1
Grade 3 tumours often metastasise to lungs

Question 24

How do dedifferentiated chondrosarcomas appear?

Answer 24

Low grade with separate high grade components that don’t produce cartilage

Question 25

How do clear cell chondrosarcomas appear?

Answer 25

Abundant clear cytoplasm

Question 26

How do mesenchymal chondrosarcomas appear?

Answer 26

Sheets of well differentiated hyaline-appearing cartilage with surrounding small round cells

Question 27

What are some benign bone tumours?

Answer 27

Simple osteoma = cranial bones, multiple is Gardner's syndrome Osteoid osteoma = <2cm, young men, mostly femur and tibia, severe nocturnal pain Osteoblastoma = involve vertebrae posteriorly, pain not responsive to aspirin

Question 28

What do osteosarcomas produce?

Answer 28

Osteoid matrix or mineralised bone

Question 29

What are some features of osteosarcomas?

Answer 29

Most cases in <20 year olds, more common in men, cases in adults secondary to Paget's/infarcts/radiation, usually long bones around knee, painful mass, sudden fracture

Question 30

What genes are linked to osteosarcoma?

Answer 30

Mutations in Rb, TP53, INK4a and MDM2

Question 31

How are osteosarcomas classified?

Answer 31

Site, grade, primary/secondary, osteoblastic/chondroblastic/fibroblastic/telangiectatic

Question 32

How do osteosarcomas spread?

Answer 32

Haematogenous spread, aggressive disease = treated with chemo and surgery

Question 33

What are some tumours of unknown origin?

Answer 33

Ewing's sarcoma, synovial sarcoma, undifferentiated pleomorphic sarcoma, giant cell tumour (osteoclastoma), aneurysmal bone cyst, pathological fracture

Question 34

What are some features of Ewing's sarcoma?

Answer 34

Malignant, aged <20, diaphysis of long bones and pelvis, painful enlarging mass, destructive lesion, primitive round cells, no obvious line of differentiation

Question 35

What are some features of synovial sarcomas?

Answer 35

Malignant, aged 20-40, deep seated mass around knee joint, also chest and head and neck, can combine areas of spindle and epithelial cells (biphasic) or b monophasic

Question 36

How should synovial sarcomas be treated?

Answer 36

Can metastasise so treat aggressively with surgery +/- chemo

Question 37

What are some features of undifferentiated pleomorphic sarcomas?

Answer 37

Malignant, deep soft tissue of extremities (often thigh), 10-20cm, necrosis and haemorrhage, pleomorphic cells, aggressive

Question 38

What are some features of giant cell tumours (osteoclasts)?

Answer 38

Benign but locally aggressive, aged 20-40, usually solitary, arise in epiphysis of femur and tibia, thin shell reactive bone, treat with curettage

Question 39

What may giant bone cells cause?

Answer 39

Arthritis-like symptoms or fractures may occur, destroy cortex and expands into soft tissue, can become cystic

Question 40

What are some features of aneurysmal bone cysts?

Answer 40

Most common aged <20, metaphysis of long bones and posterior elements of vertebral bodies, pain and swelling, lytic lesion with smooth margin and thin bone shell

Question 41

What are some associations of aneurysmal bone cysts and how are the condition treated

Answer 41

Associated with giant cell tumours and chondroblastomas; treated with curettage or resection

Question 42

What are pathological fractures?

Answer 42

Fracture through abnormal bone = spontaneous or with minimal trauma Many causes = osteopenic conditions, tumours