Solitary lytic lesions

Solitary Lytic Lesions
Dr. Y .Madhu Madhava Reddy

Solitary Lytic Lesions
• Lucent bone lesion in the medulla -well-defined,
marginal sclerosis, no expansion
• Lucent Bone Lesion In The Medulla -Well-defined,
No Marginal Sclerosis, No Expansion
• Lucent bone lesion in the medulla -ill-defined
• Lucent bone lesion in the medulla -well-defined,
eccentric expansion
• Lucent bone lesion - grossly expansile
• Subarticular lucent bone lesion

Lucent bone lesion in the medulla -well-defined,
marginal sclerosis, no expansion
• 1. Geode
• 2. Healing benign or malignant bone lesion — e.g. metastasis,
eosinophilic granuloma or brown tumour.
• 3. Brodie's abscess.
• 4. Benign bone neoplasms
• (a) Simple bone cyst* — 75% arise in the proximal humerus and
femur.
• (b) Enchondroma* — more than 50% are found in the tubular
bones of the hands. ± Internal calcification.
• (c) Chondroblastoma* — in an epiphysis. Most common sites are
proximal humerus, distal femur and proximal tibia. Internal hazy
calcification.
• 5. Fibrous dysplasia*.

Lucent bone lesion in the medulla -well-
defined, no marginal sclerosis, no expansion
• 1. Metastasis — especially from breast,
bronchus, kidney or thyroid.
• 2. Multiple myeloma*.
• 3. Eosinophilic granuloma*.
• 4. Brown tumour of hyperparathyroidism*.
• 5. Benign bone neoplasms
• (a) Enchondroma*.
• (b) Chondroblastoma*.

Lucent bone lesion in the medulla -ill-
defined
• 1. Metastasis.
• 2. Multiple myeloma*.
• 3. Osteomyelitis.
• 4. Lymphoma of bone.
• 5. Long bone sarcomas
• (a) Osteosarcoma*.
• (b) Ewing's sarcoma*.
• (c) Central chondrosarcoma*.
• (d) Fibrosarcoma and malignant fibrous histiocytoma.

Lucent bone lesion in the medulla -
well-defined, eccentric expansion
• 1.Giant cell tumour* — typically subarticular after
epiphyseal fusion (3% are metaphyseal prior to fusion).
Ill-defined endosteal margins. Septa. ± Soft-tissue
extension and destroyed cortex. Mostly long bones.
• 2. Aneurysmal bone cyst* — in the unfused
metaphysis or metaphysis and epiphysis following
fusion of the growth plate. Intact but thin cortex. Well-
defined endosteal margin. ± thin internal strands of
bone. Fluid-fluid levels on CT and MRI.

Lucent bone lesion in the medulla -
well-defined, eccentric expansion
• 3. Enchondroma* — diaphyseal. Over 50% occur in
the tubular bones of the hands and feet. Internal
ground glass appearance ± calcification within it. May
be multilocular in long bones.
• 4. Non-ossifying fibroma (fibrous cortical defect)* —
frequently in the distal tibia or femur and produces an
eccentric expanded cortex. (In a thin bone such as the
fibula central expansion is observed.) Metaphyseal.
Smooth, sharp margins with a thin rim of surrounding
sclerosis.
• 5. Chondromyxoid fibroma* — 75% in the lower limbs
(50% in the proximal tibia). Metaphyseal and may
extend into the epiphysis. Frequently has marginal
sclerosis.

Lucent bone lesion - grossly expansile
• MALIGNANT BONE NEOPLASMS
• 1. Metastases — renal cell carcinoma and thyroid; less
commonly melanoma, bronchus, breast and
phaeochromocytoma.
• 2. Plasmacytoma* — ± soft tissue extension. ± Internal
septa.
• 3. Central chondrosarcoma/lymphoma of bone/
fibrosarcoma — when slow growing may have this
appearance.
• 4. Telangiectatic osteosarcoma* — rare. Uncommon
vascular variant that mimics aneurysmal bone cyst.

• BENIGN BONE NEOPLASMS
• 1. Aneurysmal bone cyst*
• 2. Giant cell tumour*
• 3. Enchondroma* — ground-glass
appearance ± internal calcifications.

• NONNEOPLASTIC
• 1. Fibrous dysplasia* — ground-glass appearance ±
internal calcification. Modelling deformities of affected
bone.
• 2. Haemophilic pseudotumour— especially in the iliac
wing and lower limb bones. Soft-tissue swelling. ±
Haemophilic arthropathy.
• 3. Brown tumour of hyperparathyroidism* — the
solitary skeletal sign of hyperparathyroidism in 3% of
patients. Most commonly in the mandible, followed by
pelvis, ribs and femora. Usually unilocular.
• 4. Hydatid.

Subarticular lucent bone lesion
• Arthritides
• Osteoarthritis — may be multiple 'cysts' in the load-bearing
areas of multiple joints. Surrounding sclerotic margin. Joint-
space narrowing, subchondral sclerosis and osteophytes.
• Rheumatoid arthritis* — no sclerotic margin. Begins
periarticularly near the insertion of the joint capsule. Joint-
space narrowing and juxta-articular osteoporosis.
• Calcium pyrophosphate arthropathy— similar to
osteoarthritis but frequently larger and with more collapse
and fragmentation of the articular surface.
• Gout — ± erosions with overhanging edges and adjacent
soft-tissue masses.
• Haemophilia*.

Subarticular lucent bone lesion
• NEOPLASTIC
• Metastases/multiple myeloma* — single or multiple. Variable
appearance.
• Aneurysmal bone cyst* — solitary. Expansile. Narrow zone of
transition.
• Giant cell tumour* — solitary. Eccentric. Ill-defined endosteal
margin.
• Chondroblastoma* — solitary. Predilection for the proximal ends of
the humerus, femur and tibia. Contains amorphous or spotty
calcification in 50%.
• Pigmented villonodular synovitis* — mainly the lower limb,
especially the knee. Soft-tissue mass. Cyst-like defects with sharp
sclerotic margins. May progress to joint destruction.

Solitary lytic Lesions
• These lesions are sometimes referred to as
benign cystic lesions, which is a misnomer since
most of them are not cystic, except for SBC and
ABC.
• It is true that in patients under 30 years a well-
defined border means that we are dealing with a
benign lesion, but in patients over 40 years
metastases and multiple myeloma have to be
included in the differential diagnosis.

Solitary lytic Lesions
• Notice the following:
• In patients In patients > 40 years metastases and
multiple myeloma are by far the most common
well-defined osteolytic bone tumors.
• Patients with Brown tumor in
hyperparathyroidism should have other signs of
HPT or be on dialysis.
• Differentiation between a benign enchondroma
and a low grade chondrosarcoma can be
impossible based on imaging findings only.
• Infection is seen in all ages.

Fibrous dysplasia
• Fibrous dysplasia is a benign disorder characterized by
tumor-like proliferation of fibro-osseus tissue and can look
like anything.
FD most commonly presents as a long lesion in a long bone.
FD is often purely lytic and takes on ground-glass look as
the matrix calcifies.
In many cases there is bone expansion and bone deformity.
The ipsilateral proximal femur is invariably affected when
the pelvis is involved.
When FD in the tibia is considered, adamantinoma should
be in the differential diagnosis.
• Discriminator:
• If periosteal reaction or pain is present, exclude fibrous
dysplasia, unless there is a fracture.

Fibrous dysplasia
• Differential diagnosis:
– In young patients with location in proximal
humerus or femur: solitary bone cyst or
aneurysmal bone cyst.
– In eccentric locations: NOF or adamantinoma
(tibia).
– When calcifications are present: chondroid lesion
(enchondroma).

Enchondroma
• Enchondroma is a benign cartilage tumor.
• Frequently it is a coincidental finding.
• In the phalanges of the hand it frequently presents with a
fracture.
It is the most common lesion in the phalanges, i.e. a well-defined
lytic lesion in the hand is almost always an enchondroma.
In some locations it can be difficult to differentiate between
enchondroma and bone infarct.
• It is almost impossible to differentiate between enchondroma and
low grade chondrosarcoma based on radiographic features alone.
Ollier's disease is multiple enchondromas.
Maffucci's syndrome is multiple enchondromas with soft tissue
hemangiomas.

Enchondroma
• Features that favor the diagnosis of a low-grade
chondrosarcoma:
• Higher age
• Size > 5 cm
• Activity on bone scan
• Fast enhancement on dynamic contrast enhanced MR
series
• Endosteal scalloping of the cortical bone
•
Discriminators :
• Must have calcification except in phalanges.
• No periostitis.

Eosinophilic granuloma
• EG is a non-neoplastic proliferation of histiocytes and is
also known as Langerhans cell histiocytosis.
• It should be included in the differential diagnosis of any
sclerotic or osteolytic lesion, either well-defined or ill-
defined, in patients under the age of 30.
• The diagnosis EG can be excluded in age > 30.
EG is usually monostotic, but can be polyostotic.

Eosinophilic granuloma
left
Osteolytic lesion arising from the
neurocranium with associated soft
tissue swelling.
middle
Mixed lytic-sclerotic lesion, not well-
defined with solid periosteal reaction.
right
Sharply defined osteolytic lesion of
the skull. There is no 'button
sequestrum', which is more or less
pathognomonic.
Discriminator:
Must be under age 30

Giant cell tumor
• GCT is a lesion with multinucleated giant cells.
In most cases it is a benign lesion.
• Malignant GCT is rare and differentiation between benign or
malignant GCT is not possible based on the radiographs.
• GCT is also included in the differential diagnosis of an ill-defined
osteolytic lesion, provided the age and the site of the lesion are
compatible.
•
Discriminators:
• Epiphyses must be closed.
• Must be an epiphyseal lesion and abut the articular surface.
• Must be well-defined and non-sclerotic margin.
• Must be eccentric.

Giant cell tumor
• Presents as an eccentric lytic lesion with a geographic pattern of
bone destruction, but can also have a more aggressive appearance
with ill-defined borders.
• By far most giant cell tumors are seen around the knee. GCT is
located in the epiphysis with or without extension to metaphysis
and frequently abuts the articular surface.
• Most common bone tumor in adults aged 25 - 40 y.
• Differential diagnosis:
– ABC may have the same radiographic features but is found in a
younger age group.
– Chondroblastoma is also located in the epiphysis, but is seen
exclusively in the epiphysis without extention to the metaphysis and is
seen in a younger age group.
– Metastases, especially in older patients.

Non Ossifying Fibroma
• NOF is a benign well-defined, solitary lesion due to proliferation of
fibrous tissue. It is the most common bone lesion.
• NOF is frequently a coincidental finding with or without a fracture.
NOF usually has a sclerotic border and can be expansile.
• They regress spontaneously with gradual fill in.
NOF may occur as a multifocal lesion.
• The radiographic appearance is almost always typical, and as such
additional imaging and biopsy is not warranted.
Discriminators:
• Must be under age 30.
• No periostitis or pain.

NOF
• Typical
presentation as
an eccentric,
multi-loculated
subcortical
lesion with a
central lucency
and a scalloped
sclerotic margin

Osteoblastoma
• Osteoblastoma is a rare solitary, benign tumor
that produces osteoid and bone.
Consider osteoblastoma when ABC is in the
differential diagnosis of a spine lesion.
A typical osteoblastoma is larger than 2 cm,
otherwise it completely resembles osteoid
osteoma.
•
Discriminator:
• Mention when ABC is mentioned.

• Calcification or ossification of osteoid tissue
within the tumour may cause a PUNCTATE or
AMORPHOUS increase in density best seen on
CT.

Metastases
• Metastases are the most common malignant
bone tumors.
• Metastases must be included in the differential
diagnosis of any bone lesion, whether well-
defined or ill-defined osteolytic or sclerotic in age
> 40.
• Bone metastases have a predilection for
hematopoietic marrow sites: spine, pelvis, ribs,
cranium and proximal long bones: femur,
humerus.

Metastases
• Metastases can be included in the differential
diagnosis if a younger patient is known to have a
malignancy, like neuroblastoma,
rhabdomyosarcoma, retinoblastoma.
Most common osteolytic metastases: kidney,
lung, colon and melanoma.
Most common osteosclerotic metastases:
prostate and breast.
• Discriminator:
• Must be over age 40.

Multiple Myeloma
• It must be included in the differential diagnosis of any lytic bone
lesion, whether well-defined or ill-defined in age > 40.
• The most common location is in the axial skeleton (spine, skull,
pelvis and ribs) and in the diaphysis of long bones (femur and
humerus).
• Most common presentation: multiple lytic 'punched out' lesions.
• Multiple myeloma doe not show any uptake on bone scan.
Discriminator:
• Must be over age 40.
Differential diagnosis:
• multiple lesions: metastases.
• solitary lesion: chondrotumor, GCT and lymphoma.

Aneurysmal Bone Cyst
• ABC is a solitary expansile well-defined osteolytic bone lesion, that
is filled with blood. It is named aneurysmal because it is expansile.
• ABC is thought to be the result of a reactive process secondary to
trauma or increased venous pressure. Sometimes an underlying
lesion like GCT, osteoblastoma or chondroblastoma can be found.
• ABC can occur almost anywhere in the skeleton.
Discriminators:
• Must be expansile

ABC
• Radiographic hallmark is multicystic eccentric
expansion (blow-out) of the bone,with thinned out
cortex and a buttress or thin shell of periosteal
response.
• Well defined endosteal margin.
• Fluid-fluid levels on CT/MRI(represent sedimentation
of red blood cells and serum within cystic cavities).
Peripheral enhancement on contrast studies.

Solitary Bone Cyst
• Solitary bone cyst, also known as unicameral bone cyst, is a
true cyst.
• SBC frequently presents with a fracture.
Sometimes a fallen fragment is appreciated.
Predilection sites: proximal humerus and femur.
• Usually less expansion compared with ABC.
Differential diagnosis: ABC, FD when cystic.
SBC may migrate from metaphysis to diaphysis during
growth of the bone.
Discriminators:
• Must be centric

Brown tumours
• One of the manifestations of hyperparathyroidism.
• Well-defined, purely lytic lesions , cortex may be
thinned and expanded, usually hypervascular.
• Brown tumors can occur in any bone and present as
osteolytic lesions with sharp margins. Septa and ridges
may be seen.
• Differential diagnosis: ABC, metastases and GCT
depending on location and age.
• Discriminators:
• Must have other signs of HPT.

Infection
• Infection or osteomyelitis is the great mimicker of bone
tumors.
• It has a broad spectrum of radiographic features and occurs
at any age and has no typical location.
In the chronic stage it can mimic a benign bone tumor
(Brodies abscess).
• In the acute stage it can mimic a malignant bone tumor
with ill-defined margins, cortical destruction and an
aggressive type of periostitis.
• Only when there is a thick solid periosteal reaction we can
recognize the non-malignant underlying process.

Brodie Abscess
• It refers to an abscess related to focus of
chronic osteomyelitis in a bone.
• Plain film findings:
• Lytic lesion often in an oval configuration that is oriented
along the long axis of the bone
• surrounded by thick dense rim of reactive sclerosis that
fades imperceptibly into surrounding bone
• lucent tortuous channel extending toward growth plate
prior to physeal closure (pathognomonic)
• periosteal new-bone formation
• +/- adjacent soft-tissue swelling
• may persist for many months

Chondroblastoma
• Epiphysis of long bones or apophysis
• Immature skeleton ,Second decade, M>F
• epiphyses of long bones such as the humerus,
tibia and femur
• Well defined radiolucent oval lesion with thin rim
of sclerosis
• Cortical expansion
• Stippled calcification upto 50 % of cases
• Well defined endosteal margins
• Very rare malignant transformation

Chondroblastoma
• The patella, carpal and tarsal bones can be regarded as epiphysis
conceirning the differential diagnosis.
On the left a chondroblastoma located in the patella.
• Discriminators :
• must be under age 30.
• must be in the epiphysis.
D/D
• GCT -older age group (closed physis)
• clear cell chondrosarcoma - old age, large mass, absent bone edema
• osteomyelitis with abscess (e.g. Brodie abscess)
• intraosseous ganglion

Chondromyxoid fibroma
• Meta-diaphyseal
• Preferential sites -proximal tibia, femur, foot
• Eccentric-medulla
• Lobulated contour
• Matrix mineralisation unusual
• Second /third decade

Intraosseous ganglion
• An intraosseous ganglion is a benign subchondral
radiolucent lesion without degenerative arthritis.
• Tends to occur in middle age with localised pain.
• They are uni-/multilocular cysts surrounded by a
fibrous lining, containing gelatinous material.
• They occur due to mucoid degeneration of
intraosseous connective tissue perhaps due to
trauma/ischemia or
• Due to penetration of juxtaosseous soft-tissue
ganglion (=synovial herniation) into underlying
bone (occasionally).

Desmoplastic fibroma
• These extremely rare bone tumours that do not
metastasize, but may be locally aggressive. They
are considered to be a bony counterpart of soft
tissue desmoid tumours and are histologically
identical.
• Incidence is approximately 0.3%. The most
common areas of involvement include
the mandible, pelvis and femur .
• Mean age at presentation is 21, and there is no
sex predilection.

• Typically seen as a lytic bone lesions with a
geographic pattern of bone destruction
• often has a narrow zone of transition and non-
sclerotic margins
• internal pseudotrabeculation: > 90%.
• no matrix mineralisation
• widening of the host bone from gradual
apposition of periosteal new bone formation: ~
90%.

• Desmoplastic fibromas histologically are
identical to soft tissue desmoid tumors, with
abundant collagenous stroma and little
cellularity or pleomorphism. The main cell
types that are seen include: fibroblasts,
myofibroblasts, and undifferentiated
mesenchymal cells

Arachnoid granulation
• Aka Pacchionian granulation most frequently
occurs in a parasagittal location and can cause
an osteolytic, sharply circumscribed lucency
on a skull x-rays, or a filling defect in dural
venous sinuses, which can be mistaken
for dural venous thrombosis. They increase in
size with age and are seen in approximately
two-thirds of patients.

Geode
• Aka Sub chondral cyst. It is a well-defined lytic
lesion in the periarticular surfaces. A geode is one
of the common differential diagnoses of
an epiphyseal lesions (lytic).
• Presumably, one method of geode formation
takes place when synovial fluid is forced into the
subchondral bone, causing a cystic collection of
joint fluid. Another aetiology is following a bone
contusion, in which the contused bone forms a
cyst.

Geode
• Associations
• degenerative joint disease (DJD)
• rheumatoid arthritis
• calcium pyrophosphate dihydrate crystal
deposition disease (CPPD)
• avascular necrosis

Hydatid of Bone
• Rare manifestation of Echinococcosis.
• It is important to consider the possibility of
Hydatid disease of the bone as a differential
diagnosis of lucent lesions of the bone especially
in the areas where it is prevalent.
• It is most commonly seen in the spine and pelvis,
followed by the femur, tibia, humerus, skull, and
ribs.
• Osseous foci may be manifested as pain and
deformity.

Solitary lytic lesions

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