Pathology

Question 1

Answer 1

osteosarcoma
tumor cells show significant atypia and produce “lacey” osteoid (woven bone)
stromal cells show malignant characteristics with atypia, high nuclear-to-cytoplasmic ratio, and abnormal mitotic figures

Question 2

Answer 2

osteochondroma

Question 3

Answer 3

osteosarcoma.
- medullary and cortical bony destruction
- usually with a soft tissue mass
large soft-tissue mass evidenced by soft-tissue shadow
periosteal reaction (Codman’s triangle)
- characteristic blastic lesion
“sunburst” or “hair-on-end” pattern of matrix mineralization
usually mixed blastic and lytic but may be purely blastic or purely lytic
ossification (mineralized osteoid) usually detectable in tumor/bone or soft tissue mass

Question 4

Answer 4

MHE (osteochondromas) radial bowing

Question 5

Answer 5

enchondroma

Question 6

Answer 6

enchondroma
cortical expansion and thinning may be present in hands, feet (inherited diseases). may have purely lytic appearance

Question 7

Answer 7

enchondroma

Question 8

Answer 8

enchondroma
- well defined, lucent, central medullary lesions that calcify over time
- “pop-corn” stippling, arcs, whorls, rings
- minimal endosteal erosion (<50% width of cortex)

Question 9

Answer 9

osteosarcoma
tumor cells show significant atypia and produce “lacey” osteoid (woven bone)
stromal cells show malignant characteristics with atypia, high nuclear-to-cytoplasmic ratio, and abnormal mitotic figures