Benign Bone Lesions Images

Question 1

Answer 1

Fibrous Dysplasia.

This patient has polyostotic fibrous dysplasia with diffuse involvement of the pelvis as well as the proximal femurs.

Question 2

Answer 2

Fibrous Dysplasia.

This patient has polyostotic fibrous dysplasia with the involvement of the right femur as well as the supraacetabular portion of the ilium. When the pelvis is involved with

fibrous dysplasia, the ipsilateral femur on the affected side is invariably also involved.

Question 3

Answer 3

Fibrous Dysplasia.

When fibrous dysplasia affects the ribs, the posterior ribs often demonstrate a lytic expansile appearance, as in this example. When the anterior ribs are involved, they are most often sclerotic in appearance. Note also the involvement of the thoracic spine.

Question 4

Answer 4

Fibrous Dysplasia.

Polyostotic fibrous dysplasia is seen in the radius in this child. Parts of this lesion have a hazy, ground-glass appearance, whereas others are more lytic appearing. A hazy, ground-glass appearance is often present in fibrous dysplasia, but just as often, the appearance can be purely lytic or even sclerotic.

Question 5

Answer 5

Adamantinoma.

This mixed lytic and sclerotic process in the midshaft of the tibia is characteristic of fibrous dysplasia.

An adamantinoma has an identical appearance and should be considered in any tibial lesion that resembles fibrous dysplasia. Biopsy showed this to be an adamantinoma.

Question 6

Answer 6

Enchondroma.

A lytic lesion in the phalanges is most commonly an enchondroma. This is the only location in the skeleton where an enchondroma does not contain calcified chondroid matrix.

These most often present with pathologic fractures, as in this example.

Question 7

Answer 7

Bone Infarct.

These lytic lesions in the distal femurs with calcified, serpiginous borders are typical of bone infarcts. Occasionally, differentiating between a bone infarct and an enchondroma can be difficult on radiographs; however, in this example, infarcts are easily diagnosed.

Question 8

Answer 8

Enchondroma.

This lesion in the distal right femur shows the stippled punctate calcification typical of chondroid matrix seen in an enchondroma.

Question 9

Answer 9

Ollier Disease.

Multiple enchondromas are present throughout the hand. This is a typical example of Ollier disease.

Question 10

Answer 10

Maffucci Syndrome.

Multiple enchondromas in the phalanges are associated with soft

tissue phleboliths. This combination of findings invariably represents hemangiomas and enchondromas in Maffucci syndrome.

Question 11

Answer 11

Eosinophilic Granuloma (EG).

A well-defined lytic lesion is seen involving the mid- femur in this 20-year-old patient. Biopsy showed this to be EG.

Question 12

Answer 12

Eosinophilic Granuloma (EG).

Well-defined lytic lesions are present throughout the pelvis in this 24-year-old patient. In addition to the lesion around the right hip, a lesion is seen at the right sacroiliac joint. Biopsy showed this to be EG

Question 13

Answer 13

Eosinophilic Granuloma (EG).

This well-defined lytic lesion contains a bony sequestrum (arrow), which is typical of osteomyelitis or EG. Biopsy revealed this to be EG

Question 14

Answer 14

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

Question 15

Answer 15

Giant Cell Tumor.

This well-defined lytic lesion that does not have a sclerotic margin completely involves the greater trochanter. The apophyses have the same differential diagnosis as lesions in the epiphyses, which makes giant cell tumor a strong possibility in this example. Biopsy showed this to be a giant cell tumor.

Question 16

Answer 16

Giant Cell Tumor.

A large, well-defined lytic lesion in the iliac wing is seen, which does contain a sclerotic margin and does not appear to abut any articular surface. The pelvis is a good location for giant cell tumor, which this proved to be at biopsy. The usual rules for giant cell tumors such as the presence of a nonsclerotic margin do not apply in flat bones.

Question 17

Answer 17

Fibrous Cortical Defect.

A well-defined lytic lesion is seen in the medial metaphysis of this tibia (arrows), which is typical of a fibrous cortical defect.

Question 18

Answer 18

Nonossifying Fibroma (NOF).

A large, well-defined lytic lesion, which is slightly expansile with scalloped sclerotic margins, is seen in the distal tibia in this young patient. This is a characteristic appearance of an NOF. The examination was obtained for a sprained ankle and not for

this asymptomatic lesion.

Question 19

Answer 19

Nonossifying Fibroma (NOF).

A well-defined, expansile lytic lesion in the distal fibula is noted in this asymptomatic patient, which is characteristic of an NOF

Question 20

Answer 20

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.

Question 21

Answer 21

Healing Nonossifying Fibroma (NOF).

A predominantly sclerotic lesion, which is minimally expansile and well defined, is seen in the proximal humerus in this child who is asymptomatic. This is a typical appearance of a disappearing or healing NOF. With time, this lesion will melt into the

normal bone and essentially disappear.

Question 22

Answer 22

Nonossifying Fibroma (NOF).

This large, well-defined lytic lesion with faint sclerotic margins is seen in the distal femur. Because of its size, many thought it was not an NOF. The lesion underwent biopsy and was found to be an NOF

Question 23

Answer 23

Osteoblastoma.

A lytic expansile lesion involving the right T-12 pedicle ( arrow) and transverse process is seen on this anteroposterior radiograph in (A) which is seen on the CT scan (B) to extend into the vertebral body. It has intact cortices and contains some calcified matrix. This is a classic example of an osteoblastoma of the spine

Question 24

Answer 24

Metastatic Disease.

A well-defined lytic lesion is seen in the proximal femur in this 50-year-old patient who has pain associated with this lesion. Biopsy showed this to be a renal metastasis. A significant number of metastatic lesions can have a completely benign appearance, as in this example

Question 25

Answer 25

**Metastatic Disease.** A well-defined lytic lesion is seen in the proximal femur in this 50-year-old patient who has pain associated with this lesion. Biopsy showed this to be a renal metastasis. A significant number of metastatic lesions can have a completely benign appearance, as in this example

Question 26

Answer 26

**Plasmacytoma.** A large, well-defined lytic lesion is seen in the left ilium ( arrows) in this patient with multiple myeloma. This is a common location for a plasmacytoma. Like metastases, plasmacytomas often have a completely benign appearance.

Question 27

Answer 27

**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.

Question 28

Answer 28

**Plasmacytoma.** **A:** An axial MRI and **(B)** a CT through the L5 vertebral body reveal a “mini-brain” appearance, with the remaining bony struts resembling cerebral gyri and sulci in an anatomic cut brain section. This is characteristic of a plasmacytoma.

Question 29

Answer 29

**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.

Question 30

Answer 30

**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.

Question 31

Answer 31

**Aneurysmal Bone Cyst (ABC).** An axial T2-weighted image through a thoracic vertebral body shows an expansile lesion involving the posterior elements which has several fluid/fluid levels (arrows). This is a typical appearance of an ABC.

Question 32

Answer 32

**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.

Question 33

Answer 33

**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.

Question 34

Answer 34

**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.

Question 35

Answer 35

**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

Question 36

Answer 36

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

Question 37

Answer 37

**Brodie Abscess.** A: A radiograph of the proximal humerus in this child with shoulder pain reveals a well-defined lytic lesion in the medial metaphysis. B: A T2-weighted MR of the humerus shows the lesion to have high signal and an associated joint effusion. The probable site of connection to the joint can be seen (arrow), which likely represents a draining abscess. Aspiration of the joint fluid revealed pus. This is a large focus of osteomyelitis or Brodie abscess.

Question 38

Answer 38

**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.

Question 39

Answer 39

**Chondroblastoma.** A radiograph in this young patient shows a well-defined lytic lesion in the greater tuberosity of the humerus. Biopsy showed this to be a chondroblastoma.

Question 40

Answer 40

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. A biopsy was performed, which confirmed this to be a geode, or subchondral cyst; however, the biopsy could have been avoided.

Question 41

Answer 41

**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.

Question 42

Answer 42

**Healing Nonossifying Fibroma.** A radiograph of the knee in this 25-year-old patient reveals a sclerotic lesion in the proximal tibia which is a healing or resolving nonossifying fibroma.

Question 43

Answer 43

**Giant Bone Island.** A large sclerotic lesion is present in the right supra-acetabular region of the ilium (arrow), which represents a giant bone island. The slightly feathered margins of the trabeculae blending in with the normal bone, and the long axis of the lesion being in the direction of primary weight bearing, are characteristic for a bone island.