This document discusses several types of lytic bone lesions that can be seen on imaging. It describes the imaging appearance and characteristics of lesions such as fibrous dysplasia, adamantinoma, enchondroma, eosinophilic granuloma, giant cell tumor, and nonossifying fibroma. Discriminating features are provided to help differentiate these benign lytic lesions from other entities. The document emphasizes that clinical history including patient age is important when narrowing the differential diagnosis of lytic bone lesions seen on imaging studies.

1. LYTIC LESIONS OF BONE
Presented by: Dr. Devraj Kandel
Resident, MDRD, NAMS

2. INTRODUCTION
• The lytic lesions in bones may be a manifestation of a number
of bone tumors as well as tumor like conditions that are
common in day to day practice.
• Plain radiography is the modality of choice in the diagnosis.
• Other imaging modalities:
– To better elicit or delineate characteristics demonstrated
on X-ray
– To precisely define the extent of lesion
– To exclude metastasis

3. CT:
• Assessment of primary lesion and detection of potential
metastatic dissemination
• Predominant tissue present e.g., fat and calcification
• Intra-osseous and extra-osseous extent of tumor, subtle
change in medulla and cortical erosion
• Vascular nature of tumor and relation with vascular structures
• Detects more pulmonary metastasis.

4. MRI:
• Provides good soft tissue contrast with multiplanar imaging.
• Better detection of medullary changes, intra and extra
osseous extent, relation with neurovascular bundle and
joints. Thus helps to stage and plan surgery.
• Measure of tumor aggressiveness by Gd administration.
• Rate of accumulation of contrast correlates with biological
activity.
• Helps in monitoring the tumors' response to appropriate
adjuvant chemotherapy.

5. ANGIOGRAPHY:
• Delineation of involvement of major vessels and for tumor
embolisation.
• Tumor encasement and tumor vessels-much greater
frequency in malignant. (Encasement-vessel surrounded by
tumor causing abrupt narrowing).
• Tumor vessels-structures pursuing random course with an
irregular branching pattern.

6. SCINTIGRAPHY:
• May be used as first additional modality depending on the
availability of CT and MRI.
• To assess the primary lesion and to see whether it is
monoostotic or polyostotic.
• To assess the vascularity of the lesion.
• Provides extension of lesion beyond the confines of x ray.

7. Lytic lesions: FEGNOMASHIC

8. FIBROUS DYSPLASIA
• Benign congenital process that can be seen in a
patient of any age and can look like almost any
pathologic process radiographically.
• Fibrous dysplasia will not have periostitis
associated with it; therefore, if periostitis is
present, one may safely exclude fibrous
dysplasia.
• Fibrous dysplasia virtually never undergoes
malignant degeneration and is painless unless
there is a fracture.
• can be either monostotic (most commonly) or
polyostotic and has a predilection for the pelvis,
proximal femur, ribs, and skull.

9. • When it is present in the pelvis, it is invariably present in the
ipsilateral proximal femur.
• Typically has an expansile, lytic appearance in the posterior
ribs and a sclerotic appearance in the anterior ribs.
• Discriminator of fibrous dysplasia: No periosteal reaction.

15. Adamantinoma:
• When a lesion is encountered in the tibia that resembles
fibrous dysplasia, an adamantinoma should also be
mentioned.
• An adamantinoma is a malignant tumor that radiographically
and histologically resembles fibrous dysplasia.
• It occurs almost exclusively in the tibia and the jaw (for
unknown reasons) and is rare.

16. • Fig. Adamantinoma of the tibia.
Eccentric areas of bone
destruction are present
anteriorly with thinning of the
cortex. The cortex is expanded.
In addition to this abnormality,
sclerosis and ill-defined cortical
thickening are present
throughout the whole of the
tibia, which is also bowed.
These features are due to
associated fibrous dysplasia (or
a close variety sometimes
known as ossifying fibroma
which occurs only at this site).
(A) AP view. (B) Lateral view.

17. McCune Albright Syndrome.
• Polyostotic fibrous dysplasia occasionally occurs in association
with cafe au lait spots on the skin (flat pigmented skin lesions)
and precocious puberty. This complex is called McCune–
Albright syndrome.

18. • The presence of multiple lesions of fibrous dysplasia in the
jaw has been termed cherubism.
• This is from the physical appearance of the child with puffed-
out cheeks having an angelic look.
• The jaw lesions in cherubism regress in adulthood.

19. ENCHONDROMA
• Enchondromas occur in any bone formed from cartilage and
may be central, eccentric, expansile, or nonexpansile.
• They invariably contain calcified chondroid matrix except
when in the phalanges of the hands and feet.
• Most common benign lytic lesion in the phalanges.
• Discriminators:
1. Must have calcification (except in phalanges),
2. No periostitis or pain.

22. • Differentials:
1. Bone infarcts
2. Chondrosarcoma
• An infarct usually has a well-defined, densely sclerotic,
serpiginous border whereas an enchondroma does not.
• An enchondroma often causes mild endosteal scalloping,
whereas a bone infarct will not.

24. • It is difficult, to differentiate an enchondroma from a
chondrosarcoma. Clinical findings (primarily pain) serve as a
better indicator than radiographic findings- usually absent in
enchondroma.
• Multiple enchondromas occur on occasion; this condition has
been termed Ollier disease. It is not hereditary and carries a
low risk of malignant degeneration.
• The presence of multiple enchondromas associated with soft
tissue hemangiomas is known as Maffucci syndrome .This
syndrome also is not hereditary, is quite rare, and carries a
higher risk of malignant degeneration of both the
enchondromas and the hemangiomas, as well as an increased
risk for developing other malignancies.

26. EOSINOPHILIC GRANULOMA
• Eosinophilic granuloma (also known as LCH of bone) is the
most common and least severe form of Langerhans cell
histiocytosis, the other forms being Letterer–Siwe disease
and Hand–Schuller–Christian disease.
• Bony manifestations of all three disorders are similar.
• Can be lytic or sclerotic; well defined or ill defined; might or
might not have a sclerotic border; and might or might not
elicit a periosteal response.
• Can mimic Ewing sarcoma and present as a permeative
(multiple small holes) lesion.
• Occurs almost exclusively in patients less than the age of 30
years (usually <20 years); therefore, the patient’s age is the
best criterion.

27. • Because EG can look like anything, so long as the radiograph is
not of an arthritides or trauma, EG can be mentioned without
even looking at the radiograph!
• EG is most often monostotic , but it can be polyostotic.
• EG might or might not have a soft tissue mass associated.
• EG occasionally has a bony sequestrum. Other entities which
may have bony sequestra—osteomyelitis, lymphoma, and
fibrosarcoma;
• Therefore, when a sequestrum is identified, EG, osteomyelitis,
lymphoma, and fibrosarcoma should be considered.
• Clinically, EG might or might not be associated with pain;
therefore, clinical history is noncontributory for the most part.

31. GIANT CELL TUMOR
• Uncommon tumor found almost exclusively in adults in the
ends of long bones and in flat bones.
• Difficult to tell whether it is benign or malignant regardless of
its radiographic appearance and even by histology
• Most surgeons curettage and pack the lesions and consider
them benign if they do not recur.
• When malignant, they metastasize to lungs, but do so very
infrequently.
• Four classic radiographic criteria for diagnosing giant cell
tumors exist. If any of these criteria are not met when looking
at a lesion, giant cell tumor can be eliminated from the
differential diagnosis.

32. Four Criterias: (Discriminators).
1. Physes must be closed,
2. Must abut the articular surface (this rule does not apply
to flat bones such as in the pelvis or in the apophyses
which have no articular surfaces),
3. Must be well defined with a nonsclerotic margin (does
not apply is in flat bones, such as the pelvis and the
calcaneus),
4. Must be eccentric.

33. • These 4 criteria apply only to giant cell tumor and not to any
other lesion, once one of the criterias is violated, the
remainder don’t even have to be used to exclude a giant cell
tumor.
• However, it should be emphasized that these criteria only
apply to giant cell tumors of long bones. They would not
work, for instance, in the sacrum, pelvis, or the calcaneus,
three locations where giant cell tumors often occur.

34. Giant Cell Tumor. A well-defined lytic lesion without a sclerotic margin is seen
abutting the articular surface of the distal femur in a patient who has closed
epiphyses. These are all characteristics of a giant cell tumor

37. NONOSIFYING FIBROMA
• An NOF (also known as a fibroxanthoma) is probably the most
common bone lesion encountered by radiologists.
• They are benign, asymptomatic lesions that typically occur in
the metaphysis of a long bone, emanating from the cortex.
• They classically have a thin, sclerotic border that is scalloped
and slightly expansile.
• “Fibrous cortical defect” is a common synonym, although some
people divide the two lesions on the basis of size, with a fibrous
cortical defect being smaller than 2 cm in length and an NOF
being larger than 2 cm.
• If a CT or MR is obtained of an NOF, there will often appear to
be interruption of the cortex, which can be misinterpreted as
cortical destruction- which actually represents cortical
replacement by benign fibrous tissue.

38. • If the patient is older than 30 years of age, NOF should not be
included in the differential diagnosis.
• NOFs must be asymptomatic and exhibit no periostitis, unless
there is a history of antecedent trauma.
• They routinely “heal” with sclerosis and eventually disappear,
usually around the ages of 20 to 30 years.
• During this healing period, they can appear hot on a
radionuclide bone scan because there is osteoblastic activity.
• They are most commonly seen about the knee but can occur
in any long bone.
• Discriminators:
1. Must be younger than age 30 years,
2. No periostitis or pain.

41. Fig: Nonossifying Fibroma. A: A well-defined, lytic lesion that is minimally expansile is seen in the
distal tibia in this child who was examined for a sprained ankle. B: A CT examination showed
apparent cortical destruction (arrow), which was believed to be suggestive of an aggressive
lesion. Biopsy showed this to be a nonossifying fibroma. Both CT and MR will often show
apparent cortical destruction, which is merely cortical replacement by benign fibrous tissue.

43. OSTEOBLASTOMA
• Osteoblastomas have two appearances
1. They look like large osteoid osteomas and are often
called giant osteoid osteomas. (not included in
differential of lytic lesions)
2. They simulate ABCs. They are expansile, often having a
soap bubble appearance. If an ABC is being considered,
so should an osteoblastoma.
• The latter form of osteoblastomas commonly occur in the
posterior elements of the vertebral bodies, and about half of
the cases demonstrate speckled calcifications.
• A classic radiology differential is that of an expansile lytic
lesion of the posterior elements of the spine, which includes
osteoblastoma, ABC, and tuberculosis.

45. METASTATIC DISEASE
• Metastatic disease should be considered in d/d of any lytic
lesions in >40yrs
• Can have any radiographic appearance-lytic, sclerotic or
mixed.
• Mostly lytic, prostate- purely sclerotic, renal – purely lytic.
• Discriminator: Age>40yrs.

46. FIGURE . Metastatic Disease. An
expansile lesion with a soap-
bubble appearance is present in
the proximal radius in a patient
with renal cell carcinoma. An
expansile lytic lesion is a common
finding with renal or thyroid
metastatic disease.

47. MULTIPLE MYELOMA
• Most commonly presents as a diffuse permeative process in a
skeleton.
• Can present as solitary or multiple lytic lesions.
• Bubbly, lytic bone lesions of myeloma are more correctly
called plasmacytomas.
• Plasmacytomas involving a vertebral body often have a
characteristic appearance on CT and MRI called a “mini-
brain”. Unlike metastatic disease, lymphoma, and infection,
when plasmacytomas involve a vertebral body they tend to
spare some of the bone; struts of cortical bone persist, giving
the pathognomic appearance of a cut brain specimen.

48. FIGURE 55.26. Multiple Myeloma. A: A diffuse permeative pattern is present throughout
the femur in this patient with multiple myeloma. B: A lateral skull radiograph shows a
typical presentation of multiple myeloma in the skull with multiple small well-defined
lucent lesions throughout the calvarium.

50. ABC
• Named after the macroscopic appearances of a blood-filled,
expansile, sponge-like tumour containing numerous giant
cells.
• Primarily seen in less than the age of 30 years.
• ABCs typically present because of pain.
• Can occur anywhere in the skeleton but has a predilection for
the long bones and the lumbar spine (posterior elements).
• Two types of ABCs:
– Primary ABC- no known cause or association.
– Secondary ABCs- occur with GCTs, osteosarcomas, NOFs, fibrous
dysplasia and chondromyxoid fibromas.

51. • Often have fluid/fluid levels on CT or MRI.
• Differentiation from GCTs is aided by the age of the patient,
(most occur before epiphyseal fusion), and their widespread
anatomical distribution(most GCTs occurring around the knee
and wrist).
• ABC rarely extends to the articular surface and is often
central, contrast to GCTs.
• The spinal lesions need to be differentiated from
osteoblastoma and osteoid osteoma (latter two are bone
forming and show sclerotic reactions).
• Discriminators:
1. Must be expansile,
2. Must be younger than age 30 years.

52. FIG. Aneurysmal
Bone Cyst (ABC). An
expansile lytic
lesion is present in
the distal femur in
this 24-year-old
patient who
presents with pain.
This is a fairly
typical appearance
of an ABC.

53. FIGURE 55.31.
Aneurysmal Bone Cyst
(ABC). A well-defined
expansile lesion is
seen in the midshaft
of the ulna in a child
who presents with
pain in this region.
This is a characteristic
appearance of an
ABC.

55. SIMPLE BONE CYST
• Also called solitary bone cysts or unicameral bone cysts.
• Occur almost exclusively in young patients (<30 yrs).
• Always central in location.
• Common sites: Proximal humerus, Proximal femur,
Calcaneum.
• Asymptomatic unless fractured.
• Classic radiographic finding for a solitary bone cyst is the
fallen fragment sign.
• Begin at the physeal plate in long bones and grow into the
shaft of the bone.

56. • On bone scanning no abnormality develops in the blood pool
phase, in contrast to aneurysmal bone cysts.
• The delayed image demonstrates increased activity only
around the margins of the lesion, unlike fibrous dysplasia.
• The only serious differential diagnostic possibility is a
chondroma, but no calcification occurs in a simple bone cyst
unless callus has formed from a fracture.
• Discriminators:
1. Must be central
2. Must be younger than age 30 years.

57. FIG. Solitary Bone Cyst. A well-defined
lytic lesion is present in the proximal
humerus in this child who suffered a
fracture through the lesion. The location
and central appearance, as well as the
age of the patient, are characteristic of a
solitary bone cyst. A piece of cortical
bone has broken off and descended
through the serous fluid contained within
the lesion and can be seen in the
dependent portion of the lesion (arrow)
as a fallen fragment sign. A fallen
fragment sign is said to be
pathognomonic for a unicameral bone
cyst.

58. FIG. Solitary Bone Cyst. A
well-defined lytic lesion,
which is central in location,
is seen in the proximal femur
in this child. This is
characteristic of a solitary
bone cyst

59. FIG. Solitary Bone Cyst. A
well-defined lytic lesion
is seen in the calcaneus
abutting the inferior
surface, which is typical
in location and
appearance for a solitary
bone cyst. A solitary
bone cyst in the
calcaneus occurs almost
exclusively in this
location and is not
subject to pathologic
fracture as readily as
when one occurs in the
proximal femur and
humerus.

60. HYPERPARATHYROIDISM
• Osteitis Fibrosa Cystica or Von Recklinghausen’s disease of
bone; also called as brown tumor.
• So called because of brownish color due to hemorrhage and
altered blood.
• Vascularized fibrous tissue with giant cells replaces the bone
resulting cystic (lytic) lesion.
• May destroy overlying cortex resulting in pathological
fracture.
• Generally when patient’s HPT is treated, the brown tumor
undergoes sclerosis and will eventually disappear.
• Subperiosteal resorption is pathognomic and should be
sought for in radial aspect of middle phalanges, distal clavicle,
medial aspect of proximal tibia and SI joint.
• Discriminator.: Must have other evidence of HPT.

61. FIG. Brown Tumor. A: An expansile lytic lesion is seen in the fifth metacarpal
(arrows), and a second, smaller lytic lesion is seen in the proximal portion of
the fourth proximal phalanx. This patient can be noted to have subperiosteal
bone resorption, best seen in the radial aspect of the middle phalanges (B)
(arrows) as indistinct, interrupted cortex. This makes the diagnosis of
hyperparathyroidism with multiple brown tumors most likely

62. HEMANGIOMAS
• Multiple hemangiomas, also known as cystic angiomatosis or
cystic lymphangiomatosis, while uncommon, are seen more
frequently than brown tumors.
• Usually an incidental finding of multiple lytic lesions
throughout the skeleton.
• Without destructive potential.
• Should be considered when multiple lytic lesions are
encountered which are asymptomatic.
• Discriminator: Multiple lesions.

63. FIG. Cystic Angiomatosis.
Multiple lytic lesions are
seen in the pelvis and
femurs in this
asymptomatic young
woman. These were
found to be
hemangiomas.

64. INFECTION
• No reliable radiographic way to exclude a focus of infection.
• Can occur in any location and at any age.
• Might and might not be expansile, might or might not have
sclerotic border or have associated periostitis .
• When osteomyelitis occurs near jt and if articular surface is
abutted-invariably joint will be involved and show cartilage
loss and effusion or both.
• Though effusion is seen in various other conditions, it is useful
to rule out osteomyelitis when articular surface is involved
and there is no effusion.
• If a bony sequestrum is present, it should be strongly
suspected.

66. FIG. Osteomyelitis. A: A lytic lesion is present in the proximal humerus, which
has some associated periostitis laterally. B: A CT scan through this area
reveals a lytic lesion that contains a calcific density within (arrow), which is a
bony sequestrum. This is an area of osteomyelitis with a bony sequestration.

67. CHONDROBLASTOMA
• Rare lesion , seen in epiphyses (very rare in metaphysis) and
in patients less than 30 years of age.
• 40% to 60% demonstrate calcification.
• D/d of a lytic lesion in the epiphysis of a patient less than 30
years of age is simple:
1. infection (most common),
2. Chondroblastoma
3. giant cell tumor
• The carpal bones, the tarsal bones, the patella and the
apophyses (except for geodes)have a tendency to behave like
epiphyses in their d/d of lesions. Therefore, a lytic lesion in
these areas has a similar d/d as an epiphyseal lesion.

68. • The possibility of a subchondral cyst or geode should always
be considered in epiphyseal lesions which is commonly seen
in conditions like,
1. Degenerative joint disease (must have joint space narrowing,
sclerosis, and osteophytes)
2. Rheumatoid arthritis
3. Calcium pyrophosphate dihydrate crystal deposition disease or
pseudogout
4. Avascular necrosis
• Discriminators:
1. Must be less than 30 years of age
2. Must be epiphyseal.

69. Fig:Chondroblasto
ma. A plain film in
this young patient
shows a well-
defined lytic lesion
in the greater
tuberosity of the
humerus. Biopsy
showed this to be
chondroblastoma.

70. Fig: Geode. A
large, well-defined
lytic lesion in the
proximal humerus
is present, which is
associated with
marked
degenerative
disease of the
glenohumeral joint.
When definite
degenerative joint
disease is present
and associated
with a lytic lesion,
the lytic lesion
should be
considered to be a
geode.

71. CHONDROMYXOID FIBROMA
• Rare lesion resembling NOFs.
• Although chondromyxoid fibromas are cartilaginous lesions,
calcified cartilage matrix is virtually never seen
radiographically.
• Features differentiating them from NOFs are;
– can be seen in a patient of any age (NOFs<30)
– often extend into the epiphyses (NOFs do not)
– can present with pain (NOFs are painless unless #)
• Discriminators:
1. Mention when an NOF is mentioned
2. No calcified matrix

72. FIG. Chondromyxoid
Fibroma. A well-defined
lytic lesion in the distal
tibia that extends slightly
into the epiphysis is noted
on this anteroposterior
radiograph. A nonossifying
fibroma (NOF) could
certainly have this
appearance; however, this
underwent biopsy and was
found to be a
chondromyxoid fibroma.
Chondromyxoid fibromas
often will extend into the
epiphysis, as in this
example, whereas NOFs
usually will not.

73. LESIONS IN PATIENTS YOUNGER THAN 30 YEARS OF AGE
“CANES”
• Chondroblastoma
• ABC
• NOF
• EG
• Solitary bone cyst

74. AUTOMATICS
• Yonger than 30 years
– Infection
– EG
• Older than 30 years
– Infection
– Metastasis and Myeloma

75. LESIONS THAT HAVE NO PAIN OR PERIOSTITIS
“FENS”
• Fibrous Dysplasis
• Enchondroma
• NOFs
• Solitary bone cyst
When we have good FriENdS, we experience less
pain in life.

76. EPIPHYSEAL LESIONS
• Infection
• Giant Cell Tumor
• Chondroblastoma
• Geodes

77. DIFFERENTIAL FOR RIB LESIONS
“FAME”
• Fibrous Dysplasia
• ABC
• Metastatic disease and Myeloma
• Enchondroma and EG

78. MULTIPLE LESIONS
“FEEMBI”
• Fibrous Dysplasia
• Enchondroma
• EG
• Metastatic disease and Myeloma
• Hyperparathyroidism (Brown Tumor)
• Infection

79. References
• Brant and Helms’ Fundamentals of Diagnostic
Radiology, 5th edition
• Textbook of radiology and Imaging , David
Sutton, 7th edition.

80. Thank you !!!

81. Questions
• Name few osteolytic lesions of periphery
• Imaging modalities
• Differential diagnosis of lesions according to age
• Differential diagnosis of lesions according to location
• D/ds of multiple lytic lesions
• Finding in Fibrous dysplasia.
• Imaging finding in Enchondroma.
• Imaging finding in Giant cell tumor.
• Imaging finding in Non ossifying fibroma.
• Imaging finding in ABC.
• Imaging finding in simple bone cyst.
• Finding in brown cyst.