Flashcards in Pathology Deck (76):
1
What are some indications for a muscle biopsy?
Evidence of muscle disease:
- Weakness
- Symptoms (Atrophy, Fasciculation)
- Increased CK
Presence of neuropathy (Do nerve biopsy too)
Presence of vasculitis
2
In what disorders is CK high? How do we class high CK?
Dystrophies
200-300 times normal
3
In what disorders is CK intermediate? How do we class intermediate CK?
Inflammatory myopathies
20-30 times normal
4
In what disorders is CK relatively low? How do we class relatively low CK?
Neurogenic disorders
2-5 times normal
5
What can be seen in muscle dystrophy on biopsy?
Variable fibre size
Endomysial fibrosis
Fatty infiltrate + replacement:
- Clear spaces on histology
Myocyte hypertrophy
Fibre splitting
Increased central nuceli
6
Why is segmented necrosis seen in muscle dystophy biopsies?
Parts of individual muscle fibres controlled by different nuclei
7
What are ring fibres?
Striated anulets on histology
8
What are some general pathological features seen in all muscular dystrophies?
Destruction of single fibres
Prolonged
Regeneration of fibres
Fibrosis
9
A 3 year old patient is brought to you by his father. He is concerned about the fact that his son has been walking on his tiptoes a lot and falls a lot when he tries to run. On examination, the boy stands up by walking his hands towards his feet and has swollen 'woody' calves. What is the diagnosis and genetic cause of this disease?
Duchenne Muscular Dystrophy:
- Dystrophin gene mutation
- X linked recessive
10
What are pathogenic features of DMD?
Anchorage of actin to basement membrane
Uncontrolled calcium entry into cells
11
What investigations could be requested in DMD and what would the expected results be?
Serum creatinine phosphokinase:
- Raised
Muscle biopsy:
- Fibre necrosis and phagocytosis
- Regeneration
- Chronic inflammation and fibrosis
- Hypertrophy
12
What is Becker Muscular Dystrophy and how does it differ from DMD?
Essentially a variant of DMD but:
- Later onset
- Slower progress
13
At what age to DMD patients tend to die?
20
14
What tends to cause death in DMD?
Dilated cardiomyopathy
15
How is BMD inherited?
X-Linked recessive
16
'Hatchet-like' face?
Myotonic dystrophy
17
What are the two most common types of myotonic dystrophy?
DM1
DM2
18
How is myotonic dystrophy inherited?
Autosomal dominant:
- Ch19 (DM1)
- Ch3 (DM2)
19
What muscles are affected in the following stages of myotonic dystrophy:
1. Adolescent
2. Late
1. Face and distal limbs
2. Respiratory muscles
20
What are the histological features of myotonic dystrophy?
Atrophy of Type i skeletal muscle fibres
Central nuclei
Fibre necrosis
Fibrofatty replacement
21
What is the immunopathogenesis of polymyositis?
Cell-mediated immune response to muscle antigens:
- CD8+ T cells in endomysium
22
What type of fibre necrosis is seen in polymyositis?
Segmental
23
What are the clinical signs of polymyositis?
Progressive proximal muscle weakness
Pain
Tenderness
24
A patient present with difficult climbing the stairs and brushing her hair. You notice a purple heliotrope rash around her eyes.
Dermatomyositis
25
Where are immune complexes and complement deposited in dermatomyositis?
Within and around muscle capillaries
26
What sort of fibre injury is seen in dermatomyositis?
Perifascicular
27
Why lymphocytes infiltrate the muscle fibres in dermatomyositis?
B cells
CD4+ T cells
28
What is the general histological appearance of a muscle biopsy in neurogenic muscle disorders?
Small, angulated fibres (adults)
Small, round fibres (kids)
Target fibres
Fibre type grouping
Grouped atrophy
29
What causes motor neurone disease?
Progressive degeneration of anterior horn cells
30
What are signs of motor neurone disease?
Denervation atrophy
Fasciculation
Weakness
31
This is an autosomal recessive disorder characterised by degeneration of anterior horn cells in the spinal cord and muscle denervation
Spinal Muscular Atropy (Types 1-4)
32
A 27 year old woman presents to you after she notices her eyelids have been drooping and her eyes appear bulged out. She has felt very tired and has also had difficulty swallowing. She has known Grave's disease.
Myasthenia gravis
33
What is rhabdomyolysis and what does it result in?
Skeletal muscle breakdown:
- Myoglobinuria
- Hyperkalaemia
- Necrosis
- Shock
34
What are the outcomes of rhabdomyolysis?
Acute renal failure
Hypovolaemia
Hyperkalaemia
Metabolic acidosis
Disseminated intravascular coagulation
35
What drugs can commonly induce SLE?
Hydralazine
Pracainamide
36
What type of H/S reactions are the following SLE features?
1. Visceral effects
2. Haematological effects
1. Type iii H/S
2. Type ii H/S
37
Which of the following is not a potential systemic feature of SLE:
- Pericarditis
- Pleuritis
- Pleural effusions
- Splenomegaly
- Oesophageal reflux
Oesophageal reflux
38
A patient presents with abdominal pain and a cough. He has noticed some blood in his stool. He has also noticed some lower back and hip pain, which is worse at night. On examination his BP is 152/83, and there is haematuria. What is the diagnosis? What would you expect to seen on muscle biopsy and what autoantibody might be positive?.
Polyarteritis nodosa:
- Note the mononeuritis multiplex
Biopsy - Fibrinoid necrosis of vessels
pANCA positive
39
What is the basic principle behind scleroderma?
Excessive fibrosis of organs and tissue (collagen)
40
What happens to the skin in scleroderma?
Becomes:
- Tight
- Tethered
Decreased joint movement
41
What causes death in scleroderma?
Renal failure (secondary to malignant hypertension)
Severe respiratory compromise (ILD)
Cor pulmonale
Myocardial fibrosis:
- Cardiac failure
- Arrhythmia
42
What type of tumour is an osteochondroma?
Exostotic:
- Cartilage-capped bony outgrowth on bone surface
43
What are typical features of osteochondromas?
Affects those younger than 20 years
M:F equal
Develops near epiphyses of long bones
44
What are the presumed origin of osteochondromas?
Chondrocytes
45
Where do chondromas/enchondromas arise from?
Medullary cavity:
- Typically metaphyses
46
What sites are commonly affected by chondromas?
Femur
Humerus
Tibia
Hands and feet
47
What may cause multiple chondromas?
Ollier's Disease
Mafucci's Syndrome
48
True of false; Chondromas are more common in men?
True
49
Which of the following is not a histological feature of chondromas:
- Small and round
- Pyknotic
- Inside hyaline cartilage
- Lobulated
- Usually lucent
- Patchy sclerosis
Lobulated
50
What does Marffuci's Syndrome cause?
Multiple enchondromas
Haemangiomas
51
In what is the malignancy risk greater, Ollier's or Marffuci's?
Marffuci's
52
A 14 year old boy presents with a dull pain in his mid thigh. He says the pain is worse at night, but taking ibuprofen usually helps. The lesion is osteoblastic, showen woven body and a central vascular osteoid with a radiolucent nidus.
Osteoid osteoma
53
What is a peripheral sclerotic halo a histological feature of?
Osteoid osteoma
54
Where are chondroblastomas often seen?
In 10-20 year olds
Epiphyses of long bones
55
Describe the radiological appearance of a chondroblastoma
Spherical
Well-defined foci
Can extend into:
- Subarticular bone
- Joint space
- Metaphysis
56
Describe the histological appearance of a chondroblastoma
Closely packed polygonal cells
Immature chondroid
Low mitotic activity
Cytoplasma borders
'Chicken-wire' calcification
57
How do we treat benign bone tumours?
Biopsy
Curettage
Adjuvant liquid nitrogen
58
What cells do giant cell tumours originate from?
Osteoclasts
59
What is the typical presentation of a giant cell tumour?
25-40 year old
Female
Around knee
Painful
60
How does a giant cell tumour appearance radiologically?
Radiolucent
Increased peripheral density -> Soap bubble
Destruction of:
- Medulla
- Cortex
Soft tissue expansion
61
Treatment of a giant cell tumour
Surgical resection:
- Curettage
- Intralesion excision
- en bloc resection
Destroy remaining material:
- Phenol
- Cement
- Liquid nitrogen
62
Where do chordomas aries from?
Notocord remnants:
- Midline tumour
- Often sacral
63
How do chordomas appear macroscopically?
Soft, blue-grey and lobulated
Gelatinous, translucent areas
Capsule
Tracks along nerve roots
64
How do chordomas appear histologically?
Lobules and fibrous septa
Eosinophilic cytoplasm
Prominent mucus vacuoles
All of these push the nuclei to the side
65
'Sunray' spiculation
Osteosarcoma
66
What is the commonest primary malignant bone tumour?
Osteosarcoma
67
How does an osteosarcoma arise?
Malignant osteoblasts make osteoid
68
What condition may an older person possess that predisposes them to osteosarcomas?
Paget's
69
Where are osteosarcomas commonly found?
Ends of long bones:
- Femur (distal)
- Proximal tibia
- Proximal humerus
70
How to osteosarcomas appear histologically?
Osteoid
Nuclear atypia
Hyperchromasia
High mitotic rate
71
What are the three types of osteosarcomas?
Osteoblastic
Chondroblastic
Fibroblastic
72
Which of the following is not a feature of chondrosarcomas?
- Popcorn calcification on x-ray
- 3rd most common malignant tumour
- Due to malignant chondrocytes
- Obliterates marrow
- Nodules separated by fibrous bands
3rd most common:
- It is actually the 2nd most common malignant bone tumour
73
What cancers metastasise to bones as osteolytic secondary tumours?
Thyroid
Breast
Lung (SCLC)
Kidney
74
What cancer metastasises to bones as osteosclerotic secondary tumours?
Prostate
75
What is a multiple myeloma?
Malignant B cell proliferation in bone marrow
76