DYSPLASIAS OF BONE
S I R G A N G A R A M H O S P I TA L L A H O R E
Bone dysplasias are genetic disorders of the
More than 300 different bone dysplasias are
Bone dysplasias can
leg and spine
and many other
We study bone dysplasias
to improve diagnosis
and management of these rare disorders.
In addition, bone dysplasias give the rare opportunity
to study the impact of single genes on human bone
and cartilage development.
The diagnosis of these lesions is mainly
radiological and often entirely so.
is of prime importance
Genetic councelling is ,of course
Well established speciality depending on accurate
DYSPLASIAS OF BONE
also been named ToulouseLautrec syndrome,
after the French artist
Henri de Toulouse-Lautrec,
who suffered from the
rare clinical entity,
an autosomal recessive osteochondrodysplasia,
usually diagnosed at an early age
With INCIDENCE estimated to be 1.7 per 1 million
Life expectancy for a Pycnodysostosis patient is
a lysosomal storage disease of the bone
caused by a mutation in the gene that codes
the enzyme cathepsin K.
Is important for osteoclasts,
to reabsorb the bone and build new bone
The normal functioning of osteoclasts in
individuals with pycnodysostosis is disrupted by a
lack of cathepsin K,
unable to adequately reabsorb the
This process, also called remodelling, is vital for
normal bone maintenance.
The bones in individuals afflicted with
pycnodysostosis are abnormally dense
and brittle as a result of this insufficient reabsorption process.
large head with frontal and parietal bossing,
Obtuse MANDIBULAR ANGLE,
The typical 'open mouth outline ' facial
appearance is due to frontal
bossing, micrognatia, loss of the mandibular angle
prominent eyes with bluish sclerae,
underdeveloped facial bones,
Deficient growth of the maxilla and mandible
makes normal tooth alignment impossible, with
dental crowding, DENTAL ANOMALIES,
persistence of deciduous teeth resulting
a double row of teeth.
short, broad HANDS and feet with dystrophic nails
acro-osteolysis of the terminal PHALANGES
TRUNK DEFORMITIES such as
increased lumbar lordosis.
generalized sclerosis of the skeleton, including skull,
generalized sclerosis of
THE SKULL shows
open anterior fontanelle and sutures
small facial bones,hypoplastic maxilla.
non-pneumatised paranasal sinuses
flattened /obtuse mandibular angle .
sclerosis being more pronounced in the periorbital
region (“harlequin appearance” or “raccoon mask”
sign),also calvarium and the base .
open anterior and
PA skull radiography
more pronounced in the
(“harlequin appearance” or
“raccoon mask” sign),
open fontanelles and
cranial sutures, absence of
Lateral skull radiograph, age 3 years.
loss of the mandibular angle (arrow) and increased thickness of
Lateral skull film ;
• wide sutures,
of the mandible
IN THE HAND ;
terminal phalanges are partially or totally aplastic
with loss of ungual tufts.
The acromial ends of the clavicles may be aplastic.
Hand radiograph, age 3 years.
acro-osteolysis in the
distal phalanx of
thumb and index
clubbing of the terminal
medullary canals are not completely oblitreated.
coxa valga and abnormal radioulnar articulation.
failure of complete segmentation of the atlas, axis, and
the lower lumbar spine,
54-year-old man with
of the right femur and a
stress fracture in the left
femur in the same region.
Note that bones are
sclerotic and medullary
canal is visualized.
typical facial features,, open fontenella,, high arched furrowed palate and
radiological features including open cranial sutures, obtuse angle of mandible,
generalized skeletal sclerosis.
Various bone diseases should be considered in the
differential diagnosis of pyknodysostosis, particularly
osteogenesis imperfecta, and
bones,Mandib normal in size
el has no
clavicle is also
, blue sclera.
of the distal
AKA: Albers-Schönberg Disease = Marble Bone
Rare hereditary disorder
Defective osteoclast function with failure of
proper reabsorption produces sclerotic bone
AUTOSOMAL RECESSIVE TYPE
Severe form (ARO):
Also known as malignant osteopetrosis,
usually results in stillbirth/early death.
who survive present in early childhood with fractures,
diffuse marrow space obliteration leading to
ii) Intermediate severity form (IRO):
(Infantile) with cerebral calcifications ("marble brain
Osteopetrosis in a
most pronounced in
the skull base
with relative sparing
of the mandible. The
cervical vertebrae are
Neonate with typical features of autosomal recessive type of osteopetrosis.
widened costo-chondral junctions; typical metaphyseal lucent bands and
lost bony cortico-medullary differentiation.
(2) BENIGN ADULT AUTOSOMAL DOMINANT TYPE
sclerosis of the skul vault
ii) type 2
sclerosis of the skull base and pelvis
a typical "bone-within-bone" appearance of the vertebral
bodies due to endplate sclerosis,,,RUGGER JERSEY SPINE.
Benign adult autosomal dominant type
Benign adult autosomal dominant type
Cortical thickening with medullary encroachment
Erlenmeyer flask deformity
= clublike long bones due to lack of tubulization +
flaring of ends
(differentiates from other sclerosing
vertical-----in long bones,,shafts and
Arcuate------beneath the iliac crest
a young woman with autosomal dominant osteopetrosis.----sclerosis
and widening of the diploic space . The spine images show the classic
sandwich vertebrae sign (the rugger jersey spine). The femur demonstrates
increased sclerosis and an Erlenmeyer flask deformity.
One of the classical appearances of autosomal
dominant osteopetrosis is
the "bone within a bone" appearance .
Inner layer of
bone within the
also known as Leri disease
is a rare sclerosing bone dysplasia.
The name is derived from the Greek words for
due to its characteristic appearance of flowing
sclerosing mesodermal disease
with an incidence of 0.9 cases per million.
Cause is unknown
Produces thickening of the endosteum and
Peak age of presentation is 5-20 years
May be monostotic or polyostotic
involve one entire limb
not involve multiple limbs
Twice as common in lower extremities than
About 50% affected develop symptoms by age 20
Adults present with
Deformity that may progress over time
Children may present with
Leg length discrepancies
• predominantly affects the appendicular skeleton
• is most common in the long bones of the upper and
• can be seen in the hands and feet as well
• It may affect
a single bone (monostotic),
a single limb (monomelic),
or multiple bones (polyostotic).
Photographs showing the swelling in the ring finger.
A 16 year old female--- a 4 year history of progressively increasing
swelling and intermittent dull ache in the ring finger of the right hand.
no similar swelling in any other part of her body.
no history of paraesthesia or restriction of movement. There were no
similar complaints in the family
A.P. and lateral Radiographs showing
candle wax appearance in the
proximal phalanx of ring finger
Computed tomography of
cortical hyperostosis with
Five patterns have been described 1.
osteoma - like
myositis ossificans - like
osteopathia striata - like
The dripping (or flowing) candle wax sign
is seen on conventional
bone. The appearance is
that of irregular
typically occurring on
one side of the involved
bone, and has been
likened to melted wax
flowing down one side
of a candle.
which has been likened
to flowing candle wax.
The dripping candle wax sign
developmental error ---in intramembranous bone
leads to an irregular thickening of cortical bone
(cortical hyperostosis) that extends up to (but
usually not past) the articular surface.
both overproduction of bone matrix
and increased angiogenesis.
The DISTRIBUTION OF AFFECTED BONE is
thought to be due to the predilection of
melorheostosis to occur in sclerotomes (skeletal
regions innervated by a single spinal sensory
Classical appearances of
involving the right fibula and
lateral side of the foot.
AP radiograph ;
dense cortical and extra-cortical
bone formation (white arrows)
along the length of the distal fibula
to the lateral malleolus
with associated hyperostosis in the
lateral hind foot bones (black
of the hand ;
classical "candlewax" dripping
involving only the
radial side of the 3rd
Cortical lesions are
progressive and may
result in narrowing
of the medullary
canal and stenosis
of an adjacent
lumen, foramen, or
of the spinal canal.
Radiographically, the lesions show undulating
cortical hyperostosis which has been likened
to flowing candle wax.
Melorheostosis in the ribs with typical candle
CT scan will show clear demarcation between normal
and abnormal bone . CT scan is helpful to confirm or
exclude continuity of osseous and soft tissue
Noncontiguous transverse CT images through eighth (left) and ninth (right) right
posterior ribs of patient in Figure 1 show sharp delineation between normal and
affected bone segments (arrows), highlighting sclerotomal distribution.
AP radiograph right knee
longitudinal, dense bandlike areas of increased
(arrows). Note also the softtissue mineralization.
MR imaging shows heterogeneous signal intensity due
to mixture of osseous, fibrous, adipose and
cartilaginous tissue which these lesions contain
(a) MRI appearances. Sagittal, T2*-weighted, gradient echo image of the knee
showing multiple areas of intramedullary signal void (arrows). Note the
absence of patella as patellectomy was performed for severe pain. (b) Plain
radiograph in the same patient showing the area of sclerosis seen as the signal
void lesions on the MRI.
Patients with meloreostosis may have associated
cutaneous and soft tissue lesions such as
focal subcutaneous fibrosis.
features of melorheostosis, osteopathia
striata and osteopoikilosis may co-exist in so-called
These conditions may share an underlying aetiology 1.
Longitudinal dense striations
Punctate, rounded bone islands surrounding
absence of soft tissue involvement, negative scintigraphy,
no clinical complaints and autosomal dominancy
Increase in radiotracer uptake is usually present on
late phase bone scans 2.
Surgery directed at relieving contracture
radiographs are diagnostic for melorheostotic lesions.
MR imaging is useful to detect the presence and extent
of associated mineralized and nonmineralised soft
tissue masses and may obviate unwarranted biopsy
and a radical procedure.
Osteopoikilosis is a benign, asymptomatic sclerosing
dysplasis.Affects both M and F.
May be seen at any age.
Cutaneous lesions in 25%.
Inherited and spontaneous cases occur.
Sclerotic circular or ovoid lesions symmetrically
distributed in a periarticular location.
Lesions can increase or decrease in size and number in
serial radiographs or even disappear.
Lesions do not have increased bone radiotracer
multiple circular and ovoid
appear to be parallel each other
and to the long axis of the
A periarticular distribution
The main clinical
significance is that
these may be
readily from evil
entities like mets.
osteopoikilosis of the pelvis and
May be related to other sclerosing dysplasias
and when seen in combination with them, is termed
"MIXED SCLEROSING BONE DYSTROPHY."