Histology

Question 1

Answer 1

Intramedullary Osteosarc

High atypia (pleomorphism)

“lacey” osteoid

Question 2

Answer 2

chondromyxoid fibroma, with the typical stellate-shaped cells within a myxoid stroma

Question 3

Answer 3

osteochondroma, demonstrating a large benign-appearing cartilage cap and underlying osseous element

Question 4

Answer 4

osteosarcoma.

There are characteristic atypical spindle cells with high nuclear-to-cytoplasm ratio associated with lacey osteoid

Question 5

Answer 5

Chondrosarcoma

Question 6

Answer 6

synovial sarcoma

There is a classic biphasic pattern of spindle and epithelial cells

Question 7

Answer 7

Brodie’s abscess

low and high power histologic sections, respectively, showing subacute inflammation, a mixture of lymphocytes and plasma cells as well as fibrosis