MSK basic sciences (pathology, biochemistry and histology) Flashcards
(162 cards)
1
Q
what is the commonest benign tumour of bone
A
osteochondroma
2
Q
what is an osteochondroma
A
a bony outgrowth on the external surface of bone, covered with a cartilaginous cap
3
Q
where do osteochondromas typically occur
A
around the epiphysis of long bones
especially around the knee
4
Q
symptoms associated with osteochondroma
A
usually asymptomatic but may cause localised pain
5
Q
what is an enchondroma
A
an intramedullary and usually metaphyseal cartilaginous tumour
6
Q
enchondroma may undergo mineralisation and become patchy and sclerotic in appearance
true/false
A
true
7
Q
complications of enchondroma
A
may weaken the bone causing pathologic fracture
8
Q
where do enchondromas calssically occur
A
small tubular bones of the hands and feet
9
Q
what is a simple bone cyst
A
solitary unicystic fluid-filled neoplasm located in a bone
10
Q
most common locations of simple bone cysts
A
metaphyses of long bones (esp proximal femur and humerus)
talus/calcanues also
11
Q
complication of simple bone cyst
A
weakness of bone leading to pathologic fracture
12
Q
treatment of simple bone cyst
A
curettage and bone grafting +/- stabilisation
13
Q
what is an aneurysmal bone cyst
A
a cyst with many chambers which are filled with blood or serum
14
Q
where do aneurysmal bone cysts occur
A
metaphyses of long bones, flat bones and vertebral bodies
15
Q
symptoms of aneurysmal bone cyst
A
pain
locally aggressive causing cortical expansion and destruction
risk of pathological fracture
16
Q
treatment of aneurysmal bone cyst
A
curettage and grafting or bone cement
17
Q
what is fibrous dysplasia
A
diseaseof a bone usually occurring in adolescence where a genetic mutation results in lesions of fibrous tissue and immature bone
18
Q
monostotic vs polyostotic
A
monostotic affects one bone
polyostotic affect multiple bones
19
Q
the most frequent sites of fibrous dysplasia
A
head and neck
20
Q
what genetic cause is responsible for fibrous dysplasia
A
a mutation causing an abnormality in G protein signalling
21
Q
fibrous dysplasia is often associated with endocrine disorders
true/false
A
true
22
Q
effect of fibrous dysplasia on bones
A
angular growth deformity
wider bone with thinned cortices
23
Q
what deformity is produced by excessive involvement of the proximal femur in fibrous dysplasia
A
shepherd’s crook deformity
24
Q
how does fibrous dysplasia appear on a bone scan
A
intense increase in uptake during development but the lesion usually becomes inactive
25
treatment of fibrous dysplasia
bisphosphonates may reduce pain
patholigc fractures should be stabilised with internal fixation and cortical bone grafts
26
which part of bones do giant cell tumours tend to occur
metaphyseal region (can involve the epiphysis)
can extend to the subchondral bone adjacent to the joint
27
which bones/joints does giant cell tumour tend to affect
around the knee
distal radius
(other long bones, pelvis and spine)
28
giant cell tumours are completely benign
true/false
false
they tend to be locally aggressive and destroy the adjacent cortex
29
giant cell tumour presenation
pain
pathologic fracture
30
how do giant cell tumours appear on xray
'soap bubble'
31
where can giant cell tumours metastasize to
lung
32
treatment of giant cell tumour
intralesional excision with use of phenol, bone cement or liquid nitrogen to destroy remaining tumour material and reduce risk of recurrence
33
what is an osteoid osteoma
a small nidus of immature bone surrounded by an intense sclerotic halo
34
common sites of osteoid osteoma
proximal femur
diaphysis of long bones
vertebrae
35
symptoms of osteoid osteoma
intense constant pain, worse at night
36
management of osteoid osteoma
NSAIDs
may resolve spontaneously
may require CT guided radiofrequenct ablation
37
diagnosis of osteiod osteoma
bone scan (intense local uptake)
CT
38
malignant bony lesions are cnot uncommon in older age groups but are normally a result of
metastases
39
red flags for bone cancer
constant pain that's worse at night
systemic symptoms
unexplained skeletal pain
40
primary bone malignancy is more likely to occur in which age group
young people
41
a substantial ill-defined bony swelling may be
primary bone cancer - INVESTIGATE
42
signs of primary bone tumour on xray
cortical destruction
periosteal reaction
new bone formation (sclerosis/lysis)
extension into surrounding soft tissue
43
the most common primary bone tumour is
osteosarcoma
44
which gene is most commonly associated with osteosarcoma
tumour suppressor retinoblastoma gene
45
osteosarcoma most commonly affects bones surrounding which joint
the knee
46
common sites of osteosarcoma
knee
proximal femur
proximal humerus
pelvis
47
which type of metastasis is common in osteosarcoma
blood metastases
NOT LYMPH
48
treatment of osteosarcoma
adujavant chemotherapy to prolong survival
49
what is chondrosarcoma
cartilage producing primary bone tumour
50
characteristics of chondrosarcoma
| (aggressive? age group? mets?)
less aggressive than osteosarcoma
mean age 45
slow to metastasise
51
where does chondrosarcoma affect
pelvis
proximal femur
52
treatment of chondrosarcoma
surgery
not radiosensitive or responsive to chemo
53
what is ewing's sarcoma
primary bone tumour
54
which bones does ewing's sarcoma tend to affect
long bones (esp femur)
55
how are ewing's sarcomas radiologically described
onion skin pattern
56
signs of ewing's sarcoma
fever
raised inflammatory markers
warm swelling
57
staging investigations of primary bone cancer
bonce scan
CT
(MRI for involvement of vessels, muscles and nerves)
58
what margin is reccomended when removing a bone tumour
3-4 cm
59
how to joint replacements after bone malignancy surgery differ from regular joint replacements
tend to be much bigger to make up for the loss of bone
60
metastatic bone tumours commonly spread from which types of cancer
breast carcinoma
prostate carcinoma
lung carcinoma
renal cell carcinoma
thyroid carcinoma
61
breast cancer bony metastases can be blastic (sclerotic) or lytic
true/false
true
62
prostate cancer produces lytic mets
true/false
false
sclerotic mets
63
lung cancer usually gives rise to lytic mets
true/false
true
64
why are renal cell carcinoma mets described as 'blow out' lesions
they can bleed tremendously with biopsy or surgery
65
bones most frequently invovled with mets are
vertebra
pelvis
ribs
skull
humerus
long bones of the lower limb
66
patients with bony mets may present with
pathological fracture
67
if a bony lesion is found on xray, how can a primary bone tumour be excluded?
bone scan
occasionally MRI
68
which blood tests can be done when trying to detect a primary tumour after a bony met has been found?
serum calcium (hypercalcaemia)
LFTs (liver involvement)
plasma protein electrophoresis (myeloma)
FBC
U&Es
69
what sort of bone lesions are at greater risk of pathologic fracture?
very painful
lesions occupying \>50% of the diameter of the bone
cortical thinning
'at risk' areas (eg subtrochanteric area of the femur)
70
managment of bony lesions at risk of patholgical fracture
skeletal stabilisation
joint replacement
71
bony lesions not at risk of pathologic fracture can be treated with
bisphosphonates and radiotherapy
72
causes of local soft tissue swelling
inflammatory (bursitis, rheumatoid nodules)
infection (abscess)
cystic lesions (ganglion, meniscal cyst, Baker's cyst)
benign/malignant neoplasms
73
what to ask when taking a history of a soft tissue swelling
how long the lump has been present
pain
growing/fluctuating size
solitary or multiple
74
examination findings of soft tissue swelling
site
size
definition (well-defined, ill-defined)
consistency (cystic, solid, soft, hard)
surface (smooth, irregular)
mobility/fixity
temperature (abscess)
transilluminable
pulsatility
overlying skin changes
local lymphadenopathy
75
what features would suggest a benign soft tissue neoplasm
smaller size
fluctuation in size
cystic lesions
well-defined lesions
fluid filled lesions
soft/fatty lesions
76
features that suggest a malignant soft tissue neoplasm
larger lesions (\>5 cm)
rapid growth
solid lesions
ill-defined lesions
irregular surface
assocaited lymphadenopathy
systemic upset
77
extremely rapid growth of a soft tissue neoplasm is suggestive of benign/malignant neoplasm
benign
extremely fast growth is assocaited with a reactive pseudotumour
78
what structures can benign soft tissue tumours affect
non-bony connective tissues
nerves
vessels
79
what is a lipoma made of
fat
80
what is a leiomyoma made of
smooth muscle
81
what is a chondroma made of
cartilage
82
what is a rhabdomyoma made of
skeletal muscle
83
what are neuromas/schwannomas made of
nerves
84
what are haemangiomas made of
blood vessels
85
what is the most common type of soft tissue tumour
leiomyoma
they occur as fibroids in the uterus
86
what is the commonest soft tissue tumour encountered in orthopaedics
lipoma
87
what is giant cell tumour of tendon sheath
a small firm swelling usually found on the flexor tendon sheath of a finger
88
what is the macroscopic and microscopic appearance of a giant cell tumour of tendon sheath
macroscopic - pigmented lesion
microscopic - multinucleated giant cells and haemosiderin
89
what are malignant soft tissue tumours arising from the connective tissues known as?
sarcomas
90
what is an angiosarcoma
malignant tumour arising from blood vessels
91
most common cause of angiosarcoma
complication of previous radiotherapy
92
what is a fibrosarcoma
rare tumour of unknown origin
93
what is a liposarcoma
malignant tumour arising from fat
94
where do liposarcomas occur
deep fatty tissue, most often within the abdomen
95
what is a rhabdomyosarcoma
malignant tumour of skeletal muscle
96
what age do sarcomas most commonly present
50-70
97
where are ganglion cysts found
around synovial joints or synovial tendon sheaths
98
why are ganglion cysts not truly cysts
they do not have an epithelial lining
99
what is a bursa
a small fluid filled sac lined by synovium around a joint which prevents friction between tendons, bones, muscle and skin
100
which bursae are often affected by bursitis
pre-patellar
olecranon
1st metatarsal head (bunion)
101
bursitis can be caused by
infection
gout
repeated pressure
trauma
102
characteristics of sebaceous cysts
squamous epithelium lining that produces abundant keratin
103
what is released from a ruptured sebaceous cyst
degenerate keratn (cheesy substance)
104
what does an abscess consist of
neutrophils
infective and cellular debris
(infection organism)
105
what can cause an abscess
cellulitis
bursitis
penetrting wound
infected sebaceous cysts
106
treatment of abscess
incision and drainage
107
what is a pseudotumour
a tumour that mimics a neoplasm but is a reactive/inflammatory lesion
108
what is myositis ossificans
progressive ossification at a site of injury
109
what is the most common site of AVN
femoral head
110
AVN is most common in which group of people
chronic alcoholics
111
what is creeping substitution associated with
AVN
112
what age group is affected by osteochondritis
children and young adults
113
what is AVN
ischaemic necrosis of bone
114
what sites are most prone to AVN
femoral head
femoral condyles
head of humerus
capitellum
proximal pole of scaphoid
proximal talus
115
how can AVN be caused by fracture
fracture disrupts the blood supply to a portion of bone
116
causes of AVN
fracture
idiopathic
alcoholism
steroids
hyperlipidaemia
increased coagulability
117
what type of imaging can detect early changes in AVN
MRI
118
what type of bone defect is osteoporosis
a quantitave defect
119
what are the characteristics of osteoporosis
reduced bone mineral density and increased porosity
(normal bone quality, just not enough of it)
120
complications of osteoporosis
increased risk of fracture
121
what is the WHO definition of osteoporosis
bone mineral density less than 2.5 standard deviations below the mean peak value of young adults of the same race and sex
122
what is osteopaenia
an intermediate stagoe of osteoprosis where bone mineral density is 1-2.5 standard deviation below mean peak value
123
loss of bone density in osteoporosis is due to
gradual slow down of osteoblastic activity
124
why do females tend to lose more bone density after the menopause
increase in osteoclastic bone resorption with the loss of protective effects of oestrogen
125
what is type 1 osteoporosis
post menopausal osteoporosis
126
risk factors for type 1 osteoporosis
smoking
alcohol abuse
lack of exercise
poor diet
127
what is type 2 osteoporosis
osteoporosis of old age
128
risk factors for type 2 osteoporosis
chronic disease
inactivity
reduced sunlight exposure
smoking/alcohol
poor diet
129
what fractures are most common in ype 1 osteoporosis
colles fracture
vertebral insufficiency fractures
130
fractures associated with type 2 osteoporosis
femoral neck fractures
vertebral fractures
131
secondary osteoporosis can be caused by
steroid use
alcohol abuse
malnutrition
chronic disease (CKD, malignancy, RA)
endocrine disorders (cushing's, hyperthyroidism, hyperparathyroidism)
132
diagnosis of osteoporosis
DEXA scan (measures bone mineral density)
133
serum calcium and phosphate levels in osteoporosis
normal
134
treatments for osteoporosis
calcium and vit D supplements
bisphosphonates (reduce osteoclastic resorption)
Desunomab (monoclonal antibody which reduces osteoclast activty)
strontium (increase osteoblast replication and reduces resorption)
135
risks of HRT for treatment of osteoporosis
increased risk of breast and endometrial cancer and DVT
136
137
what sort of defect is osteomalacia
qualitative
138
what is osteomalacia
abnormal softening of the bone due to deficient mineralisation of osteoid (immature bone) secondary to inadequate amounts of calcium and phosphorus
139
what is the difference between osteomalacia and ricketts
ricketts affects children
140
what are the principal causes of osteomalacia
insufficient clacium absorption from the intestine (lack of dietary calcium or a deficiency o or resistance to the action of vitamin D)
phosphate deficiency due to increased renal losses
141
specific causes of osteomalacia
malnutrition
malabsorption
lack of sunlight
hypophosphataemia
long term anticonvulsant use
CKD
142
presentation of osteomalacia
bone pain (pelvis, spine, femora)
deformities from soft bones (more ricketts)
pathological fractures
hypocalcaemia (paraesthesiae, muscle cramps, irritability, fatigue, seizures, brittle nails)
143
serum calcium, phosphate and ALP in osteomalacia
low Ca
low PO4
high ALP
144
treatment of osteomalacia
vitamin D therapy
phosphate supplementation
145
146
what causes primary hyperparathyroidism
benign adenoma
hyperplasia
malignant neoplasia (rare)
147
what does overproduction of PTH result in
hypercalcaemia
148
symptoms of hyperparathyroidism
fatigue, depression, bone pain, myalgia, nausea, thirst, polyuria, renal stones, osteoporosis
149
serum calcium and phosphate in hyperpara
Ca high
PO4 normal/low
150
what is secondary hyperpara
physiological overproduction of PTH secondary to hypocalcaemia usually casued by vitamin D deficiency or CKD
151
what are brown tumours
lytic bone lesion caused by hyperpara
152
treatment of hyperpara
removal of the adenomatous gland
treatment of underlying cause (vit D supplementation)
153
what is paget's disease
a chronic disorder which results in thickened, brittle and mis-shapen bones
154
paget's disease affects the whole skeleton
true/false
false
it normally affects one or a few bones
155
what causes the increased bone turnover in paget's disease
increased osteoclast activity
156
paget's pathophysiology
increased osteoclast activity leads to increased bone turnover
osteoblasts become more active to correct excessive resorption
new bone is formed, but fails to remodel sufficiently and the resulting bone is brittle despite its increased thickness and density
157
158
which bones are commonly affected by paget's disease
pelvis
femur
skull
tibia
ear ossicles (conductive deafness)
159
presentation of paget's disease
asymptomatic (incidental finding)
arthritis
pathologic fracture
deformity
pain
high output cardiac failure (increased blood flow through pagetic bone)
160
xray appearance of paget's disease
enlarged bone with thickened cortices and coarse, thickened trabeculae with mixed areas of lysis and sclerosis
161
what do bone scans show in paget's disease
increased uptake in the affected bone(s)
162
treatment of paget's disease
bisphosphonates (inhibit osteoclasts)
calcitonin (in extensive lytic disease)
joint replacment
