L15 Bone disease 2 Flashcards
What are gigantism and acromegaly?
- Overproduction of growth hormone (typically due to an adenoma of the pituitary gland)
- Gigantism = overproduction before growth is complete
- Acromegaly = overproduction after growth is complete (only affects the small bones of hands and feet, mandibular condyles, facial soft tissues- lips, nose, tongue)
What are the effects of acromegaly on the skull?
- Enlarged thickening of bones
- Enlargement of paranasal sinuses including maxillary sinuses
- Enlargement of pituitary fossa (if caused by tumour of pituitary gland)
What are the effects of acromegaly on the jaws?
- Enlarged mandible
- Enlargement of ID canal
- Spacing of anterior teeth due to jaw and tongue enlargement
What are the 3 types of hyperparathyroidism?
- Primary: caused by pathology of the parathyroid gland e.g. adenoma
- Secondary: glands are fine, but there is underlying disease e.g. chronic renal disease, causing low calcium levels causing more PTH to be excreted
- Tertiary: when long-standing secondary hyperparathyroidism starts to behave like primary hyperparathyroidism
What is the function of parathyroid hormone?
Regulates serum calcium and phosphate.
Affects the bones, kidneys and small intestine.
Describe the events that occur due to hyperparathyroidism.
- Increased PTH mobilises calcium from the skeleton
- Increase in serum calcium, decrease in serum phosphate
- Serum alkaline phophatase increases
- Stones, bones, abdominal groans and psychic moans
What are the effects of hyperparathyroidism on the skull?
Osteopenia aka pepper-pot skull.
Speckled appearance of skull vault.
What are the effects of hyperparathyroidism on the jaws?
- Osteopenia = ground glass/orange peel appearance
- Loss of lamina dura and other corticated structures e.g. floor of maxillary antrum
- No bony expansion
- May be localised Brown tumours
Describe Brown tumours.
- Typically displace the teeth
- May be lightly corticated
- Often multilocular in appearance
- When enucleated they have a brown appearance due to the haemosiderin within them
What are the 2 types of fibrous dysplasia?
- Monostotic fibrous dysplasia: affects 1 bone only, most common type, typically starts in childhood and then ceases
- Polyostotic fibrous dysplasia: affects multiple bones, more common in women, cafe au lait spots, 2 types
What are the 2 types of polyostotic fibrous dyplasia?
- Jaffe-Lichenstein type: skin lesions without endocrine disturbance
- McCune-Albright syndrome: endocrine disturbance and skin lesions. Comprises polyostotic fibrous dysplasia, patchy melanotic skin pigmentation (café au lait spots), precocious puberty (especially in females)
What are the oral manifestations of fibrous dysplasia?
- Jaws often involved (Mx>Md)
- Present in childhood or adolescence
- Gradually increasing painless swelling of the jaw, producing facial asymmetry
- Causes tooth displacement
- Usually smooth surfaced
- Maxillary lesion may involve the sinus, zygomatic process, floor of orbit
- More pronounced buccally than palatally
Describe the radiographic features of polyostotic fibrous dysplasia.
- Localised lesion of ground glass bone
- Margins of ground glass merge with normal bone
- Loss of lamina dura around tooth
- Enlargement of bone
- Teeth displaced
- Antrum may be displaced
Describe the histology of fibrous dysplasia.
- Replacement of normal bone by fibrous tissue containing islands and trabeculae of metaplastic bone
- Newly formed bone trabeculae form delicate, irregular shapes known as Chinese characters
How is fibrous dyplasia managed?
- Conservative surgical removal to reduce deformity
- Best to perform surgery once bone growth has ceased
- Bisphosphonate therapy
- Cannot be treated with radiotherapy
What is osteoporosis circumscripta?
- Feature of Paget’s disease
- Bone being replaced by fibrous tissue, clear margin between normal bone and abnormal bone
Describe the histopathology of Paget’s disease.
- Disorganised bone remodelling producing combinations of osteoclastic and osteoblastic activity
- Early stages: osteoclastic activity
- Late stages: osteoblastic activity
- Reversal lines produce mosaic appearance in bone
What is cherubism?
- Autosomal dominant condition
- More common in men
- Disease of childhood
- Bilateral expansion of jaws
- Affects posterior mandible or posterior maxilla
- If maxilla affected it gives a cherubic appearance (check enlargement, orbital floors moved upwards making eyes more upwards)
- Treatment: slow progression so intervention isn’t always necessary
- Surgical intervention if patient is severely affected
What does this image show?
The histology of giant cell lesions:
- Large numbers of multinucleated giant cells
Describe the radiological features of giant cell lesions.
- Often multilocular
- Well defined corticated outline
- Uniformly radiolucent with radiopaque septa
- Displaces teeth
- Expansion of buccal/lingual bone
- No tooth resorption
What does this image show?
Cherubism, giant cell lesions.
Describe the main features of multiple myeloma.
- Middle aged pts
- Multiple sites including skull vault and mandible
- Variable sizes
- Round shape
- Punched out appreance, well defined and non-corticated
- Uniformly radiolucent
- If large, may lead to pathological fracture
Explain the main features of langerhans’ cells histiocytosis.
What does this image show?
Langerhans’ cell histiocytosis.
Floating teeth, uniformly radiolucent, round.
