Flashcards in Pathology Deck (76):
What are some indications for a muscle biopsy?
Evidence of muscle disease:
- Symptoms (Atrophy, Fasciculation)
- Increased CK
Presence of neuropathy (Do nerve biopsy too)
Presence of vasculitis
In what disorders is CK high? How do we class high CK?
200-300 times normal
In what disorders is CK intermediate? How do we class intermediate CK?
20-30 times normal
In what disorders is CK relatively low? How do we class relatively low CK?
2-5 times normal
What can be seen in muscle dystrophy on biopsy?
Variable fibre size
Fatty infiltrate + replacement:
- Clear spaces on histology
Increased central nuceli
Why is segmented necrosis seen in muscle dystophy biopsies?
Parts of individual muscle fibres controlled by different nuclei
What are ring fibres?
Striated anulets on histology
What are some general pathological features seen in all muscular dystrophies?
Destruction of single fibres
Regeneration of fibres
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
What are pathogenic features of DMD?
Anchorage of actin to basement membrane
Uncontrolled calcium entry into cells
What investigations could be requested in DMD and what would the expected results be?
Serum creatinine phosphokinase:
- Fibre necrosis and phagocytosis
- Chronic inflammation and fibrosis
What is Becker Muscular Dystrophy and how does it differ from DMD?
Essentially a variant of DMD but:
- Later onset
- Slower progress
At what age to DMD patients tend to die?
What tends to cause death in DMD?
How is BMD inherited?
What are the two most common types of myotonic dystrophy?
How is myotonic dystrophy inherited?
- Ch19 (DM1)
- Ch3 (DM2)
What muscles are affected in the following stages of myotonic dystrophy:
1. Face and distal limbs
2. Respiratory muscles
What are the histological features of myotonic dystrophy?
Atrophy of Type i skeletal muscle fibres
What is the immunopathogenesis of polymyositis?
Cell-mediated immune response to muscle antigens:
- CD8+ T cells in endomysium
What type of fibre necrosis is seen in polymyositis?
What are the clinical signs of polymyositis?
Progressive proximal muscle weakness
A patient present with difficult climbing the stairs and brushing her hair. You notice a purple heliotrope rash around her eyes.
Where are immune complexes and complement deposited in dermatomyositis?
Within and around muscle capillaries
What sort of fibre injury is seen in dermatomyositis?
Why lymphocytes infiltrate the muscle fibres in dermatomyositis?
CD4+ T cells
What is the general histological appearance of a muscle biopsy in neurogenic muscle disorders?
Small, angulated fibres (adults)
Small, round fibres (kids)
Fibre type grouping
What causes motor neurone disease?
Progressive degeneration of anterior horn cells
What are signs of motor neurone disease?
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)
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.
What is rhabdomyolysis and what does it result in?
Skeletal muscle breakdown:
What are the outcomes of rhabdomyolysis?
Acute renal failure
Disseminated intravascular coagulation
What drugs can commonly induce SLE?
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
Which of the following is not a potential systemic feature of SLE:
- Pleural effusions
- Oesophageal reflux
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?.
- Note the mononeuritis multiplex
Biopsy - Fibrinoid necrosis of vessels
What is the basic principle behind scleroderma?
Excessive fibrosis of organs and tissue (collagen)
What happens to the skin in scleroderma?
Decreased joint movement
What causes death in scleroderma?
Renal failure (secondary to malignant hypertension)
Severe respiratory compromise (ILD)
- Cardiac failure
What type of tumour is an osteochondroma?
- Cartilage-capped bony outgrowth on bone surface
What are typical features of osteochondromas?
Affects those younger than 20 years
Develops near epiphyses of long bones
What are the presumed origin of osteochondromas?
Where do chondromas/enchondromas arise from?
- Typically metaphyses
What sites are commonly affected by chondromas?
Hands and feet
What may cause multiple chondromas?
True of false; Chondromas are more common in men?
Which of the following is not a histological feature of chondromas:
- Small and round
- Inside hyaline cartilage
- Usually lucent
- Patchy sclerosis
What does Marffuci's Syndrome cause?
In what is the malignancy risk greater, Ollier's or Marffuci's?
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.
What is a peripheral sclerotic halo a histological feature of?
Where are chondroblastomas often seen?
In 10-20 year olds
Epiphyses of long bones
Describe the radiological appearance of a chondroblastoma
Can extend into:
- Subarticular bone
- Joint space
Describe the histological appearance of a chondroblastoma
Closely packed polygonal cells
Low mitotic activity
How do we treat benign bone tumours?
Adjuvant liquid nitrogen
What cells do giant cell tumours originate from?
What is the typical presentation of a giant cell tumour?
25-40 year old
How does a giant cell tumour appearance radiologically?
Increased peripheral density -> Soap bubble
Soft tissue expansion
Treatment of a giant cell tumour
- Intralesion excision
- en bloc resection
Destroy remaining material:
- Liquid nitrogen
Where do chordomas aries from?
- Midline tumour
- Often sacral
How do chordomas appear macroscopically?
Soft, blue-grey and lobulated
Gelatinous, translucent areas
Tracks along nerve roots
How do chordomas appear histologically?
Lobules and fibrous septa
Prominent mucus vacuoles
All of these push the nuclei to the side
What is the commonest primary malignant bone tumour?
How does an osteosarcoma arise?
Malignant osteoblasts make osteoid
What condition may an older person possess that predisposes them to osteosarcomas?
Where are osteosarcomas commonly found?
Ends of long bones:
- Femur (distal)
- Proximal tibia
- Proximal humerus
How to osteosarcomas appear histologically?
High mitotic rate
What are the three types of osteosarcomas?
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
What cancers metastasise to bones as osteolytic secondary tumours?
What cancer metastasises to bones as osteosclerotic secondary tumours?
What is a multiple myeloma?
Malignant B cell proliferation in bone marrow