Bone Pathology I Flashcards
What are the categories of Osteodystrophy
- Genetic Diseases
- Metabolic Diseases
- Others or unknown causes
What Osteodystrophic diseases are considered genetic diseases
Osteogenesis imperfecta Osteoporosis Cleidocranial Dysplasia Cherubism Hypophosphatasia Vitamin D-resistant rickets
What Osteodystrophic diseases are considered metabolic diseases
Rickets
Steomalacia
Hyperparathyroidism
Renal osteodystrophy
What Osteodystrophic diseases are classified as either others or unknown causes
Paget's disease of bone Fibrous dysplasia Aneurysmal bone cyst Idiopathic osteosclerosis Focal osteoporotic bone marrow defect Bisphosphonate-associated osteonecrosis of jaw
Most common inherited bone disease
Osteogenesis imperfecta
Pathology of Osteogenesis imperfecta
Mutations in collagen type I
Symptoms and presentation of Osteogenesis imperfecta
Bone fragility and deformity Joint hyper extensibility Hearing loss Blue sclera \+-opalescent teeth (dentinogenesis imperfecta)
- Abnormal collagen result in bones with a thin cortex and osteoporosis which are soft and prone to fracture.
- Bones characterized by bowing, angulation and deformity
Describe the different forms and inheritability of Osteogenesis imperfecta
Type I-IV
Autosomal dominant or recessive
- Severity varies
Rare form with florid cemento-osseus dysplasia
Management of Osteogenesis imperfecta
Physiotherapy
Orthopedic therapy
Bisphosphonates, IV or oral, for more severe patients but long term outcome in pediatric patients unknown
What is Osteopetrosis (Marble bone disease)
Defect in osteoclast function
Describe the genetic inheritance of infantile osteopetrosis
Autosomal recessive
Characteristics of infantile osteopetrosis
Severe
Sclerotic skeleton
Marrow failure (anemia, hepatosplenomegaly, osteomyelitis)
Facial deformity
Neurological deficit (paralysis, blindness, deafness)
Describe the genetic inheritance of Adult osteopetrosis
Autosomal dominant
- Mild, 40% asymptomatic
Dental considerations for Osteopetrosis
Jaws affected
Although bones denser, they are more fragile
Fractures
Fracture and osteomyelitis after both extraction
Management of Infantile osteopetrosis
Prognosis poor
Management of Adult osteopetrosis
Variable prognosis, some long term survival
- Bone marrow transplantation
- Other experimental protocols
What is Cleidocranial Dysplasia
Defect of differentiation of osteoblasts and a subset of chondrocytes caused by mutations
Describe the genetic inheritance of Cleidocranial dysplasia
Autosomal dominant or somatic mutation
Clinical characteristics or features of Cleidocranial Dysplasia
Short stature Frontal bossing Patent fontanels Late closure of cranial sutures Absence or hypoplasia of the clavicles
Dental characteristics of Cleidocranial Dysplasia
Retention of deciduous teeth
Delayed eruption of permanent teeth
Supernumerary teeth
+- narrow high arched plate
Prognosis and management of Cleidocranial Dysplasia
- Prognosis good and no treatment for the developmental bone disorder
- Dental treatment planning based on clinical findings
What is the genetic inheritability of Cherubism
Autosomal dominant or spontaneous mutation
Clinical characteristics of Cherubism
Bilateral post. mandibular painless swelling
Maxillary swelling push the orbital base upward
Upturned eyes
Rounded eyes
When is cherubism most common?
Average 7 y/o (14 months - 12 y/o)
Progress until puberty then slowly regress
Radiographic features of Cherubism
- Radiolucency
- Usually multilocular
- Bilateral of posterior mandible
- Often from mandibular notch on one side to contralateral side
- Usually with maxillary involvement also
Histopathology of Cherubism
Giant cell granulomas
What is the natural history of Cherubism
stabilization around puberty and often regression
What is hypophosphatasia
Mutations of non-specific alkaline phosphatase (liver-, bone-, or kidney-type)
What is the genetic inheritability of Hypophosphatasia
Variable degrees of expression
- Autosomal dominant or recessive
Clinical characteristics of Hypophosphatasia
- Reduces levels of ALP in liver, bone, kidney, intestine and serum
- Increased levels of blood and urinary phosphor-ethanolamine
- Bone abnormalities similar to rickets
Dental: Premature loss of primary (or permanent) teeth due to lack of cementum
What is the genetic inheritability of Vitamin D-resistant Rickets (Hereditary hypophosphatemia)
X-linked dominant trait
severity varies
Caused by mutations
Clinical characteristics of Vitamin D-resistant Rickets
- Decreased reabsorption of phosphate from renal tubules
- Decreased intestinal absorption of calcium
- Hypophosphatemia
- Shortened lower body segment?
Dental:
- Large pulp horns extending to DEJ
- Cleft in dentin
- Periodical abscess
Vit D deficiency during infancy = ?
Rickets
Vit D deficiency during adulthood = ?
Osteomalacia
Describe the clinical characteristics of Rickets
Growth retardation
Prominence of the costochondral junctions
Bowing of the legs
Describe the clinical characteristics of Osteomalacia
Weak bone
Fractures
Diffuse skeletal pain
Describe Primary Hyperparathyroidism
Parathyroid adenoma (80-90%) or hyperplasia
Demographics of Primary Hyperparathyroidism
> 60 y/o
Increase in females
Pathology of Primary Hyperparathyroidism
Increase in PTH = Increase bone resorption = increase serum Ca
Describe Secondary Hyperparathyroidism
Secondary to chronic renal disease
- Vitamin D Activation in kidney decreases
- Absorption of calcium in intestine decreases
- Serum calcium decreases = PTH increases
Clinical characteristics of Hyperparathyroidism
- Stones, bone and abdominal groans
- Kidney stones, calcifications in b.v.
- Subperiosteal resorption of the phalanges of the fingers
- Loss of lamina dura
- Ground glass trabecular pattern
- Brown tumor (radiolucency)
- Renal osteodystrophy (secondary hyperpara)
- Duodenal ulcers
- Histo of brown tumor: indistinguishable from central giant cell granuloma
What is Renal Osteodystrophy
Complication of secondary hyperparathyroidism in end-stage renal stage
- Enlargement of the jaws
- Radiography: Ground glass pattern
- Histology: fibre-osseous lesion
Describe Paget’s disease of bone
Accelerated resorption and deposition of bone
- ultimately osteoblasts win and bones become sclerotic, larger and brittle
Demographics of Paget’s disease of bone
Geographic variance in prevalence
White
Male predominant
Older than 40 yrs
Clinical characteristics of Paget’s disease of bone
Monostotic but increased Polyostotic
- Bone pain
- Deformity
- Weakened bone
- Can be asymptomatic
Etiology of Paget’s disease of bone
Paramyxovirus infection;
Genetic factor
Radiographic features of Paget’s disease of bone
Well defined RL –> Mixed RL/RO –> Cotton wool-like RO
Generalized hypercementosis
How to diagnose Paget’s disease of bone
- Clinical
- Radiographic
- Laboratory (increase alk phosphatase; usually normal Ca, increase urinary hydroxyproline)
- Scintigraphical findings
Complications of Paget’s disease of bone
Fracture
Malignant transformation
What is Fibrous dysplasia
- A postzygotic mutation
- Bones become replaced with fibrous tissue and immature bone
Gene encodes stimulatory G protein alpha subunit, activates adenylyl cyclase –> cAMP, Affects differentiation of preosteoblasts, prolonged activation stimulates endocrine receptors
Anatomic distribution of Fibrous Dysplasia
80-85% Monostotic
Polyostotic
Craniofacial
Polyostotic with café au lait spots (Jaffe-Lichtenstein syn. )
Polyostotic with café au lait spots (McCune-Albright Syn.)
Clinical features and demographics of Fibrous Dysplasia
- 1-2 decades
- equal in males and females
- Long bone: pain and fracture
- Craniofacial: expansion and disfigurement, crosses suture lines
- Craniofacial involved about 1/3
- CFFD may compress vital structures
- Optic nerve compression may result in blindness
McCune-Albright Syndrome
Somatic mosaicism accounts for clinical diversity
- Hyperendocrine function: > gonads, thyroid
- Sexual precocity, > girls
- Café au last spots within first two years, irregular margins
- Polyostotic, > long bones, CFFD in 1/4
- CFFD morbidity assoc with > GH
Radiographic features of Fibrous Dysplasia
- Early lesions radiolucent –> mixed –> ground glass opacity
- Margins blend
- cortical expansion
- cortical reaction absent
Demographic and locations of Central Giant Cell Granuloma
Female > Male
Before 30 years of age
70% in mandible
Anterior jaws and classically crosses the midline
Clinical features of Central giant Cell granuloma
Nonaggressive
- Asymptomatic, Slow growth, no cortical perforation or root resorption
Aggressive
- Pain, rapid growth, cortical perforation and root resorption
Radiographic features of Central giant Cell Granuloma
Unilocular to multilocular radiolucency
Margins tend to be noncorticated
+- Cortical perforation or expansion
+- Root resorption
What is an Aneurysmal Bone Cyst
An intraosseous accumulation of variable-sized, blood-filled spaces surrounded by cellular fibrous tissue with giant cells
Demographics of Aneurysmal Bone Cysts
Most common in long bones or vertebrae
2% in jaws
Children and young adults
Clinical features of Aneurysmal bone cyst
Rapid swelling, pain
Unilocular or multi-locular RL
Radiographic findings of Aneurysmal bone cyst
Radiolucent, unilocular but > multilocular
Cortex often expanded and thinned or perforated
Borders can be well defined or diffuse
Demographics of Idiopathic Osteosclerosis
Blacks, Chinese, Japanese
No gender predilection
90% in Md, > 1st molar
80% contact tooth root
Clinical features of Idiopathic Osteosclerosis
Characteristically no pain or expansion
Rarely root resorption
Easily confused with condensing osteitis but tooth is VITAL
Radiographic findings of Idiopathic Osteosclerosis
Well defined radiopacity, may be asymmetric
Typically without a radiolucent halo but blends
80% contact a tooth root
Occasionally show root resorption
Diagnosis can usually be made on clinical and radiographic features
What is Focal Osteoporotic Bone Marrow defect
An asymptomatic radiolucent lesion
Demographics of Focal Osteoporotic Bone Marrow defect
Middle aged females
- theory: secondary to low grade anemia
70% in posterior mandible
Often at site of previous extraction
Radiographic findings of Focal Osteoporotic Bone Marrow defect
radiolucency often with fine internal trabeculation
Diagnosis of Focal Osteoporotic Bone Marrow defect
Incisional biopsy may be necessary to establish diagnosis
