Musculoskeletal Pathology: Ewing Sarcoma

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What is the most common site for giant cell tumors?

Soft tissue surrounding the joint

Proximal fibula

Distal femur and proximal tibia (correct)

metaphyseal of long bone

What percentage of giant cell tumors develop lung metastasis?

6%

4% (correct)

2%

8%

What is the typical age of onset for giant cell tumors?

Adolescence

Third decade of life (correct)

Childhood

Elderly

What is the composition of a giant cell tumor?

Primitive mononuclear cells and reactive osteoclasts Signup and view all the answers

What is the radiographic appearance of a giant cell tumor of the proximal fibula?

Predominantly lytic and expansile with cortical destruction Signup and view all the answers

What is the most common site for an Aneurysmal Bone Cyst (ABC)?

Vertebra Signup and view all the answers

Which cells are typically seen in the background of an Aneurysmal Bone Cyst?

Neoplastic cells Signup and view all the answers

What structures are the septa in an Aneurysmal Bone Cyst composed of?

Plump uniform fibroblasts, multinucleated giant cells, and woven bone Signup and view all the answers

What age group is most commonly affected by Aneurysmal Bone Cysts?

Adolescents Signup and view all the answers

What is a common symptom associated with Aneurysmal Bone Cysts?

Pathologic fracture Signup and view all the answers

What type of tumor is Ewing sarcoma?

A highly malignant tumor Signup and view all the answers

What percentage of primary malignant bone tumors is Ewing sarcoma?

10% Signup and view all the answers

Which of the following is NOT a characteristic of Ewing sarcoma?

The cell of origin is exactly known Signup and view all the answers

What is the most common genetic abnormality found in Ewing sarcoma?

Balanced translocation Signup and view all the answers

What are the two genes involved in the characteristic balanced translocation of Ewing sarcoma?

EWSR1 and FLI1 Signup and view all the answers

What is the most common tissue of origin for Ewing sarcoma?

Bone Signup and view all the answers

What type of lesion is described in the text?

Aneurysmal bone cyst Signup and view all the answers

What is the appearance of the lesion as described in the text?

Hemorrhagic and spongelike Signup and view all the answers

Which of the following is NOT mentioned as a feature of the aneurysmal bone cyst in the text?

Malignant cells Signup and view all the answers

What type of cells are indicated by the red arrows in the image description?

Osteoclast-type giant cells Signup and view all the answers

What is the function of the structure indicated by the yellow arrow in the image description?

Bone formation Signup and view all the answers

What is the primary cause of uncontrolled growth and abnormal differentiation in long bones?

The resultant protein binds DNA and dysregulates transcription Signup and view all the answers

Where do tumors typically arise in long bones?

The medulla, middle part, and diaphysis (shaft) Signup and view all the answers

What radiographic feature is described as an 'onion skin' appearance?

Periosteal reaction of multiple layers Signup and view all the answers

What is the morphological feature of Ewing sarcoma cells observed under light microscopy?

Primitive, small, round cells with minimal cytoplasm Signup and view all the answers

What is the significance of Homer-Wright rosettes in Ewing sarcoma?

They represent primitive neuron-like structures Signup and view all the answers

How does the behavior of giant cell tumors compare to completely benign and malignant tumors?

They are in the middle, more benign but can cause damage Signup and view all the answers