B6.077 Bone Tumors (Part 2)

Question 1

epidemiology of unicameral (simple) bone cyst

Answer 1

common lesion found in kids

occasionally in adults

Question 2

location of unicameral (simple) bone cyst

Answer 2

centrally located in the bone (medullary canal)

usually metaphyseal

Question 3

presentation of unicameral (simple) bone cyst

Answer 3

usually presents with fracture

no known risk factors

Question 4

treatment of unicameral (simple) bone cyst

Answer 4

observation
steroid injection
BM injection
curettage / grafting
**30% recurrence with any treatment, likely due to underlying vascular abnormality
goal is to keep kids achieving their developmental milestones

Question 5

appearance of unicameral (simple) bone cyst on xray

Answer 5

sharp distinction
lytic areas of fluid / blood
ground glass area where lytic lesions healed

Question 6

unicameral (simple) bone cyst on histo

Answer 6

spindle cells
open spaces
no necrosis / mitotic activity

Question 7

epidemiology of osteoid osteoma

Answer 7

teens and early 20s

M:F = 2:1

Question 8

location of osteoid osteoma

Answer 8

< 2 cm
appendicular skeleton (femur or tibia 50%)

Question 9

symptoms of osteoid osteoma

Answer 9

painful
excess PGE2 produced by proliferating osteoblasts (causes swelling within bone, leading to pain)
pain relieved by aspirin ( can be used long term)

Question 10

treatment of osteoid osteoma

Answer 10

radiofrequency ablation

Question 11

appearance of osteoid osteoma on xray

Answer 11

active bone around lesion

presence of nidus within lesion

Question 12

osteoid osteoma on histo

Answer 12

nidus surrounded by reactive bone
spindles in background
osteoblastic rimming

Question 13

presentation of osteoid osteoma in the spine

Answer 13

painful scoliosis
lesion on concave side of spinal curve
-PGE causes contraction of muscles

Question 14

appearance of osteochondroma on xray

Answer 14

sharp transition
medullary canal of bone contiguous with medullary canal of lesion
cortex of bone contiguous with cortex of lesion

Question 15

appearance of osteochondroma on CT

Answer 15

bone present behind cartilage cap on lesion

reactive bone

Question 16

appearance of osteochondroma on histo

Answer 16

looks like a physes, but less organized

cartilage cap on reactive bone

Question 17

what is an osteochondroma

Answer 17

exostosis

benign cartilage capped outgrowth that is attached to the skeleton by a bony stalk

Question 18

hereditary osteochondromas genetics

Answer 18

multiple hereditary exostosis (multiple osteochondromas)

EXT1 and EXT2 mutations

Question 19

solitary osteochondromas genetics

Answer 19

85% EXT1 mutation

Question 20

what is the EXT gene

Answer 20

in growth plate chondrocytes

Question 21

prognosis / treatment of osteochondroma

Answer 21

1% risk of transformation to chondrosarcoma per lesion
multiple lesions increases risk
don’t usually remove unless symptomatic

Question 22

periosteal chondroma location

Answer 22

sits on the surface of bone
arises in only one bone (don’t need to look for other lesions)
arises from cambium layer of periosteum

Question 23

treatment of periosteal chondroma

Answer 23

usually resected due to risk of enlargement

Question 24

periosteal chondroma on imaging

Answer 24

intact cortex with mineralized lesion on top

Question 25

periosteal chondroma on histo

Answer 25

more cellular than a lesion within bone | has lacunae with cartilage and matrix and fibrous tissue

Question 26

presentation of enchondroma

Answer 26

frequently presents in hand after fracture | radiographically and histologically more aggressive in the hand

Question 27

treatment of enchondroma

Answer 27

usually surgical intervention in the hand intervention not necessary in other locations unless concern about more aggressive lesion -follow for increasing lytic component (growth without mineralization)

Question 28

appearance of enchondroma on histo

Answer 28

less matrix and more cellularity than normal cartilage | histologically inactive

Question 29

appearance of enchondroma on xray

Answer 29

popcorn areas within bone

Question 30

typical location of enchondromas

Answer 30

usually solitary metaphyseal region develop from rests of growth plate cartilage

Question 31

syndromes associated with enchondromas

Answer 31

Ollier's disease- multiple enchondromas Maffucci syndrome - enchondromatosis + soft tissue hemangiomas -increased risk of malignancy in all body parts, unrelated to lesions

Question 32

prognosis of enchondromas

Answer 32

small risk (<1% per lesion) of malignancy transformation

Question 33

location of chondroblastoma

Answer 33

epiphyseal or apophyseal (next to growth plates)

Question 34

epidemiology of chondroblastoma

Answer 34

occurs in adolescents

Question 35

presentation of chondroblastoma

Answer 35

presents with acute onset of pain and swelling of the adjacent joint similar to an infected joint

Question 36

evaluation of chondroblastoma

Answer 36

should be urgent, to not miss infected joint and to provide pain relief MRI and labs can help rule out infection

Question 37

treatment of chondroblastoma

Answer 37

biopsy curettage grafting

Question 38

differentiation of low grade liposarcoma from lipoma

Answer 38

slightly more cellular presence of lipoblasts MDM2 increased in liposarcoma (test done after excision)

Question 39

treatment of lipomas

Answer 39

not all need to be removed | if consistent with fat on MRI, can be watched if less than 5 cm in greatest dimension and are not enlarging

Question 40

assessment of lipoma

Answer 40

assess for ring chromosome or MDM2 amplification (proto-oncogene amplified in liposarcomas)

Question 41

second most common soft tissue sarcoma

Answer 41

liposarcoma

Question 42

appearance of fibromatosis on xray

Answer 42

indentation in bone due to pressure effect of soft tissue mass

Question 43

histo appearance of fibromatosis

Answer 43

sheets of spindle cells and collagen

Question 44

characteristics of fibromatosis

Answer 44

benign but locally aggressive no ability to metastasize usually in response to trauma (injury response that doesn't turn off) may respond to estrogen (BCP can make it bigger) hardest lesion that you'll palpate, usually fixed

Question 45

epidemiology of fibromatosis

Answer 45

slightly higher incidence in women

Question 46

treatment of extra-abdominal desmoid

Answer 46

confirm diagnosis (vs low grade fibrosarcoma) if symptomatic or enlarging, resect with wide margins avoid amputation amputation may be required if limb is at risk

Question 47

non surgical treatment of extra abdominal desmoid

Answer 47

variable course, may regress responds to RT possible use of SERMs or chemo for unresectable but symptomatic lesions

Question 48

what is an undifferentiated pleomorphic sarcoma

Answer 48

most common type of soft tissue sarcoma | unknown tissue type

Question 49

epidemiology of UPS

Answer 49

occurs in middle aged to older adults

Question 50

screening of UPS

Answer 50

CT of chest, as with all sarcomas

Question 51

treatment of UPS

Answer 51

radiation and surgical resection (wide margin) | chemo if at risk of spread or has metastasis

Question 52

features of UPS on histo

Answer 52

large cells with mitotic activity spindle cells clumping