Msk -- Tumors

Front 1

1. What are the typical features of Ewing Sarcoma?
2. What can this appearance be confused with?
3. How can you differentiate Ewing sarcoma from osteosarcoma?
4. Where does Ewing Sarcoma metastasize to?

Back 1

1. Permeative ill-defined lytic destruction, well defined purely lytic lesion, mixed lytic/sclerotic pattern, honeycomb appearance. The periosteal reaction may be laminated, spiculated, or solid. Soft tissue mass is present in most cases and is often bulky and disproportionately larger than the bony destruction.
2. Clinical and radiographic findings often simulate osteomyelitis.
3. Involvement of flat bones and axial skeleton is more common with Ewing sarcoma than osteogenic sarcoma.
4. Mets usually involved the lungs or other bones.

Front 2

1. What are the imaging features of aneurysmal bone cyst?
2. What are primary and secondary ABC?
3. What bone tumors have associated ABC components within them?
4. How are ABCs treated?

Back 2

1. Eccentric, lucent expansile lesion that can balloon out the overlying intact cortex. It has a narrow zone of transition with no periosteal reaction. Most commmonly located in the metaphysis.
2. Primary ABC is thought to be related to trauma. Secondary ABCs occur as part of existing bone tumors.
3. GCT, chondroblastoma, fibrous dysplasia, osteoblastoma, telangiectatic osteosarcoma.
4. ABC's are treated with curettage and packing to avoid fracture.

Front 3

1. Is multiple hereditary exostoses AD or AR?
2. What are the 2 morphologic types?
3. What is the etiology?
4. What signs indicate malignant degeneration?
5. What is Trevor disease?

Back 3

1. AD
2. Sessile and pedunculated. Sessile is more common.
3. Like enchondromas which arise from cartilaginous rests left behind by the growth plate, osteochodromas also arise from cartilage that is separated from the growth plate.
4. If cartilage cap is >2 cm, indistinct bony margin, area of lucency.
5. Osteochondroma arising from the epiphysis. Note that most osteochondromas arise from the metaphysis of long bones and point away from the jont surface.

Front 4

1. What is the location of solitary bone cysts in relation to the medullary cavity? What are some common locations of solitary bone cysts?
2. How are solitary bone cysts treated?

Back 4

1. Solitary bone cysts are found in the center of the medullary cavity. Whereas, ABCs are found eccentrically. The majority of solitary bone cysts are located in the long bones but they can also be fond in the calcaneus and pelvis. They arise in the metaphysis but may migrate into the diaphysis with skeletal growth.
2. Solitary bone cysts are not painful unless they fx; unlike, ABCs which are painful. Therapy is directed at preventing pathologic fractures in weight-bearing bones and includes steroid injection, curettage, and packing with bone fragments.

Front 5

1. What is the difference between fibrous cortical defect and NOF?
2. Can NOF enlarge?
3. What is the typical appearance of NOF?

Back 5

1. Size. Fibrous cortical defects are confined to the cortex. They appear as a radiolucent area in the cortex with an almost blister-like appearance. There may be mild cortical expansion without periosteal reaction. The larger nonossifying fibroma may appear with a sclerotic rim and trabeculation.
2. NOFs may grow to become quite large before sclerosis and healing.
3. Multilobulated, radiolucent lesion located eccentrically and varying from 2cm - 7cm, oriented along the long axis of the bone, with a well-defined rim of sclerosis, and scalloped margins that can expand the bone.

Front 6

1. What is the typical appearance of osteosarcoma?
2. What is characteristic about pulmonary metastases from osteosarcoma?
3. How is osteosarcoma treated?

Back 6

1. Ill-defined lytic lesion with mineralized osseous matrix in a cloud-like morphology that often extends beyond the normal contours of the bone. The more aggressive the tumor, the more lytic its appearance. Aggressive periosteal reaction (Codman triangle) and associated soft tissue mass.
2. Pulmonary metastases may ossify and cavitate resulting in pneumothorax.
3. Neoadjuvant therapy to debulk the tumor, followed by resection and postresection chemotherapy in the absence of metastatic disease.

Front 7

1. Does fibrous dysplasia have a rim of sclerosis?
2. What bones are frequently affected?
3. What is particular about fibrous dysplasia affecting the skull base?
4. What is Shepherd's crook deformity?
5. What syndromes are associated with polyostotic fibrous dysplasia?
6. What is the etiology of FD?
7. What is cherubism?

Back 7

1. Fibrous dysplasia may or may not have a rim of sclerosis. Sometimes, a reactive thick rind of dense sclerosis is seen encircling the ground glass lucency as the osteoblasts attempt to wall off the fibrous lesion. However, absence fo sclerotic border does not exclude fibrous dysplasia.
2. Femur, tibia, ribs, skull base, and facial bones (frontal bossing). (NOTE: LCH likes to affect the calvarium; not facial bones or skull base).
3. FD affecting the skull base may be sclerotic.
4. Extensive involvement of the proximal femur by FD.
5. Mc-Cune Albright and Mazabraud.
6. The marrow becomes replaced by fibrous tissue. The variable amount of osteoid accounts for a wide range of radiographic densities in the bone.
7. Familial fibrous dysplasia characterized by bilateral expansile lesions in the mandible associated with cystic areas.

Front 8

1. What are the radiographic findings of chondroblastoma?
2. What are the MRI findings of chondroblastoma?
3. What are the common sites of involvement?

Back 8

1. Round epiphyseal lesion with well-defined margins and a narrow zone of transition. A thin rim of sclerosis may also be seen. Stippled calcifications are common.
2. MRI will show a lobular T2 hyperintense mass (cartilage) with substantial bone marrow edema which can look aggressive. Therefore, always ask for radiographs. There can also be joint invasion and extension into the adajent soft tissues and bone.
3. Femur, humerus, and tibia are the most common. However, 10% of chondroblastoams aris within epiphyseal equivalents (aposphysis, carpal, and tarsal bones) and are thus frequently found in the talus and calcaneus.

Front 9

1. What is Histiocytosis?
2. What are the imaging findings of LCH?

Back 9

1. Histiocytosis refers to a group of disorders with abnormal proliferation of histiocytes (macrophages). There are a number of different histiocytoses, one of which is Langerhans cell histiocytosis (LCH), a disease characterized by clonal proliferation of a Langerhans cell, a special kind of macrophage.
2. Flat bone involvement is more common than long bone involvement. Involvement of the spine leads to vertebral plana. Involvement of the skull leads to lytic lesion with beveled edges. Bony sequestrum can be seen. On MRI it can have an aggressive appearance mimicking osteomyelitis and malignancy.

Front 10

1. What syndromes are associated with multiple enchondromas?
2. What is the inheritance pattern?
3. What are the typical imaging features of enchondromas?
4. What findings suggest malignant degeneration?

Back 10

1.
- Multiple enchondromas = Ollier's syndrome
- Multiple enchondromas + hemangiomas = Maffucci's syndomre (increased risk of multiple malignancies).
2. Non-hereditary
3.
- Metaphyseal lesion with lobulated contour located in the center of the medullary cavity containing rigns and arcs of calcification. Slowly expansile lesion yields a thinned cortex with cortical penetration. Nearly 50% of enchondromas are found in the small tubular bones of the hand.
4. Sudden increase in size, cortical destruction, pain raise question of malignant degeneration.

Front 11

1. What is the most common soft tissue tumor in children?
2. What are the common locations of rhabdomyosarcoma?
3. What are the histologic forms of rhabdomyosarcoma?

Back 11

1. Rhabdomyosarcoma
2. Head and neck, GU, and skeletal system.
3. Several histologic forms: embryonal, alveolar, pleomorphic and undifferentiated.

Front 12

Lymphoma/leukemia

Back 12

- leukemia lines: transverse, radiolucent metaphysical bands in large joints.
- subperiosteal new bone formation along the shafts of long bones that can be smooth, lamellar, or sunburst in appearance.
- focal destructive process with a moth eaten appearance
- diffuse sclerosis