Imaging-Bone Tumors Flashcards
What is the gold standard for imaging of bone tumors? What modality is ideal for looking at soft tissue infiltration? Evaluating bone cortex? Evaluating metastatic sites?
Radiography. MRI = soft tissue. CT = looking at cortex. Bone scintgraphy = multiple tumor sites.
What factors go into your analysis of bone tumors?
Age, sex, bone involved, location on bone, pattern of growth and composition of the lesion.
A 9 year old presents with ankle pain. What is the most likely diagnosis?
Chondroblastoma. He is a child, it is in a long bone and confined to the epiphysis.
A 20 year old presents with shin pain. Imaging shows an intracortical lesion in the tibia. What is the most likely diagnosis?l
Osteoid osteoma. Note sclerotic intracortical lesion in a 20 year old.
What are the different categories of bone lesion margins?
I (geographic, less aggressive). II (Motheaten). III (Permeative most aggressive)
What type of lesion is this?
This is a nonossifying osteoma which is a 1A geographic lesion. This has little risk. Note the well circumscribed, sclerotic lesion indicative of a benign lesion.
What type of lesion is this?
Giant cell tumor which is a 1B geographic tumor without a sclerotic margin. This has a risk of metastasis.
What type of lesion is this?
Chondrosarcoma/Osteosarcoma/Giant cell tumor which is a 1C geographic tumor. This has a risk of metastasis and malignancy. Note that you could draw a circle around the tumor but it has an irregular border.
What type of lesion is this?
Motheaten. Note the larger lesions and narrower zone of transition compared to permeative. It is difficult to determine margins in some places of the bone.
What type of lesion is this?
Permeative, all differential diagnoses are malignant (Ewing, Osteosarcoma, Fibrosarcoma, Myeloma) except for osteomyelitis. Note wide zone of transition that is also ill-defined.
When do radiographs show lesions in the bone?
When the cortical bone is destroyed.
How can the periosteum image determine a nonaggressive tumor?
Thick layer of cortex = non-aggressive, keeping the tumor covered by cortes.
How can the periosteum tell you if a tumor is aggressive?
Elevated/broken periosteum = aggressive tumor (Codman triangle/hair on end/onion skin/sunburst)
What is indicated in this image?
Sequestrum (devascularized dead bone)
What characteristics of a tumor suggest chondroid matrix?
Arcs, whorls, rings or stippled
What characteristics of a tumor suggest osteoid matrix?
Ivory or cloud-like (denser than normal cortical bone)
What kind of lesion is this?
Fatty. Notice how dense it is on MRI
What type of lesion is this?
1B. Note well-defined, non-scleroitic border, no cortical disruption, no mineralized matrix and medullary expansion of the tumor. This is not a malignant tumor.
What type of lesion is this?
1C. Note indistinct margin with sclerotic margin and in tact cortex. This is not a malignant tumor.
What tumor can you rule out if you do not see osteoid in this image? What do you start thinking about then if you note the tumor is in the diaphysis of a 19 year old?
Osteosarcoma. These tumors produce osteoid. You start thinking about Ewing sarcoma, note Codman triangle.
What about this image points you towards osteomyelitis?
Permeative lytic tumor that crosses the joint
Where is the involucrum and drainage sinus in this image?
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