Bone Path

Front 1

Bone anatomy

Back 1

Diaphysis: parallel edges
Metaphysis: Fluted edges
Epiphysis: between growth plate & articular surface

Front 2

Where is cancellous bone seen?

Back 2

Epiphysis and Metaphysis ONLY

NOT in diaphysis

Front 3

Tumor metaphysis of long bone of extremity (KNEE), in skeletally immature patient

Back 3

Osteosarcoma

Front 4

Osteosarcoma

age distribution?

Back 4

Bimodal

10-20 & 50+

Front 5

20y.o. Caucasian with diaphyseal tumor

Back 5

Ewing sarcoma
exclusively in whites

Front 6

Ewing sarcoma

Age distribution?

Back 6

Most < 20
But can occur at any age

Front 7

Age distribution for chondrosarcoma?

Back 7

Steadily increases with age

Front 8

Most common epiphyseal tumor in childhood?

Back 8

Chondroblastoma

Front 9

Malignant bone tumor by age:

<5?
5-15?
>40?

Back 9

Metastatic neuroblastoma

OS or ES

Met or myeloma

Front 10

T/F: Most bone tumors less than 6 cm are benign.

Back 10

True

Front 11

Radiologic calcifications suggest what type of tumor?

Back 11

Cartilagenous

Front 12

Firm bony lesion distal femur 20M

Back 12

Osteochondroma
3 layersL perichondrium, cartilage, bone

Front 13

Osteochondroma imaging?

Back 13

Sessile or pedunculated
Calcifications
Continuity of marrow space to lesion

Front 14

Syndrome with multiple osteochondromas?

Back 14

Multiple hereditary exostosis

AD
Increased risk of chondrosarcoma (40% or 1% per year).

Front 15

Px in MHE patients that do develop chondrosarcoma?

Back 15

Same as general population

Front 16

Back 16

Enchondroma
Hands & feet most common
Benign cartilage, islands

Radiolucent or mineralized

Front 17

Syndrome of multiple enchondromas?

Back 17

Ollier disease

Usually unilateral
Failure of enchondral ossification

Front 18

Syndrome of multiple enchondromas AND hemangiomas?

Back 18

Maffucci Syndrome

Severe skeletal malformations
High risk of other malignanies (ov, CNS, panc...)

Front 19

Back 19

Periosteal chondroma
Prox humerus & femur most common

** SHARPLY MARGINATED from cortex (vs osteochondroma). See the cortex without infiltration by the lesion.

Can look very ugly = need radiology not to call chondrosarc.

Front 20

What is this called?
Imaging?

Back 20

CHICKEN WIRE CALCIFICATION
Chondroblastoma

Imaging: small lytic lesions +- sclerotic rim

** Often has osteoclast-like giant cells.

Front 21

How to ID CB vs. GCT of bone?

Back 21

Giant cell tumor of bone usually occurs in >20y.o. and does NOT have a sclerotic rim on imaging

Front 22

Epiphyseal lesion 20M

histologic features?
treatment?

Back 22

Chondroblastoma
-Epiphyseal
- 10-30 year olds, m>f
Biphasic lesion (cellular & matrix)
Round nuclei with fine chromatin. LINEAR GROOVES COMMON. Abundant pink cytoplasm with retraction = fried egg.
CHICKEN WIRE CALCIFICATION
Osteoclast-like giant cells

25% recur > curettage

Front 23

What is the pink stuff in CB?

Back 23

CHONDROID! NOT osteoid.

(Osteosarcomas DO NOT occur in the epiphysis)

Front 24

tibia or foot lesion in patient <30y

Radiology?
Site?

Back 24

Chondromyxoid fibroma

METAPHYSEAL LESION
Sharply marginated oval zone of rarefaction (looks grossly like yellow custard)

Front 25

Chondromyxoid fibroma
Treatment?
px?

Back 25

Currettage

25% recur

Front 26

Back 26

Chondromyxoid fibroma

MONOPHASIC lesion

Spindled cells
may see focal atypia
osteoclast-like giant cells at edge
CHUNKY calcification
zonation (hypocellular in center, more cellular at periphery)

Lobules of myxoid cartilage

ZONATION

Front 27

How is the myxoid cartilage diff from hyaline cart?

Back 27

Hyaline cartilage has LACUNAE; myxoid cartilage does not, the cells are just swimming in matrix

Front 28

Knee lesion

Back 28

Synovial chrondromatosis

mature cartilage with fibrous or synovial lining

joints (hip, knee, TMJ...)

Front 29

50M

Site?
Imaging?

Back 29

Chondrosarcoma

Axial skeleton; Pelvis (ileum), prox femus & humerus

Metaphysis or diaphysis

Imaging: Geographic lesion (geographic lesions usually benign except here); Fusiform expansion with cortical thickening and erosion; mineralization (non-homogeneous, ring&fleck)

Front 30

#1 px indicator in chondrosarcoma?

Back 30

Histologic grade

Front 31

Types of chondrosarcoma

Back 31

Primary (arising in previously normal bone) (90%)

Secondary (arising in previous enchondroma / etc)

Dedifferentiated (well-diff cartilagenous lesion, usu well-diff CS, + high grade noncartilagenous sarcoma, usu MFH)

Periosteal

Clear Cell (rare, low grade)

Mesenchymal (rare, small round blue cell tumor + cartilage matrix)

Front 32

Tumor?

Histologic features?

Treatment?

Back 32

Chondrosarcoma, grade 2.

Abundant hyaline cartilage
Atypical chondrocytes (may be subtle) with binucleation
Irregular lobules
PERMEATION of bony trabeculae

Can have osteoblasts build bone onto surface (reactive phenomenon, NOT osteosarc)

TM: Surgery

Front 33

How to tell well-diff CS from enchondroma?

Back 33

SITE!
CS rarely involves hands & feet, and enchondromas there can have atypical features

CS is more cellular & permeates bone. More CYTOLOGIC atypia

**Enchondromas (& OC) should STOP growing at bone maturity

Front 34

30y.o. spine lesion

Back 34

Mesenchymal chondrosarcoma

small round blue cells + cartilage

Poor long-term px

Front 35

#1 site of mesenchymal CS?

Back 35

H&N (JAW!!!!)

spine, rib, ileum

Front 36

75M pelvis lesion

Back 36

Dedifferentiated chondrosarcoma
BIPHASIC tumor

Low-grade hyaline cartilage + high grade sarcoma (usu MFH)

Front 37

Dediff chondrosarc vs. chrondroblastic osteosarcoma

& why is this impt?

Back 37

The cheese analogy!

Dediff CS: swiss cheese. cheese + holes, no mixing. cartilage & high grade sarcoma do not mix; abrupt transition

CB-OS: blue cheese. All mixed together. high grade cartilage & osteoid...

Importance: Px
Dediff CS 0% long term survival
CB-OS: 80%

Front 38

30M femur

tumor?
bone site?

Back 38

Clear cell chondrosarcoma

EPIPHYSIS
clear cells
can have GIANT CELLS within tumor (only CS to do this)
Good px

Front 39

Classic epiphyseal lesions?

Back 39

giant cell tumor of bone
chondroblastoma
clear cell chondrosarcoma
Clear cell chondrosarcoma

Front 40

Teenage boy with severe nocturnal pain relieved by aspirin

Dx?
Therapy?

Back 40

Osteoid osteoma

within cortex
Imaging: discrete well-defined

Mature bone, osteoblasts. Random anastomosis. fibrovascular stroma but no cartilage or elements

<1cm

Therapy = Ablation (RFA)

Front 41

20M... site?

Back 41

SPINE! (transverse & spinous processes (not the vertebrae))

Osteoblastoma
>1cm

Mature bone, osteoid, lined by osteoblasts, "soldiers in a row", monomorphous

Front 42

Proximal humerus 17M.

buzzword?

classic sites?

Back 42

Codman's triangle of Osteosarcoma

Due to periosteal elevation from expansion of intramedullary osteosarcoma.

Usually a mixed osteoblastic and osteolytic lesion, with cortical destruction and extension into soft tissue

Distal femur, prox humerus & tibia

METAPHYSEAL lesion!

Front 43

presentation of osteosarcoma?

Back 43

usually <30y.o. (if >40, suspect predisposing condition i.e. Paget's)

weeks to months of worsening pain, with or without palpable mass.

10% have fracture

Front 44

Type?


What is the thinnest osteoid called?

Back 44

Osteoblastic osteosarcoma

50% of conventional osteosarcoma

MAKES OSTEOID
Can be difficult to ID but is dense, pink, amorphous, curvilinear

Thinnest osteoid is called FILIGREE. Looks like tendrils

Front 45

Dx?
matrix?

Back 45

Chondroblastic osteosarcoma (25% of conventional OS)

Makes high-grade hyaline cartilage

Front 46

how to ID chondroblastic osteosarcoma vs. chondrosarcoma?

Back 46

LOCATION
CS - EPIPHYSIS
OS - METAPHYSIS

Histology
Dediff CS: usually low-grade cartilage with high-grade sarcoma. Separate.
CB-OS: HG cart & HG osteoid; all mixed together.

Front 47

Type?

Back 47

Fibroblastic osteosarcoma (25%)

High-grade spindle cells with minimal osseous formation and some cartilage. (looks like MFH but with some osteoid. can be subtle!)

Front 48

#1 px indicator in conventional osteosarcoma?

Back 48

Response to pre-op chemo.

the histologic subtypes do NOT have differences in prognosis

Front 49

#1 metastatic site for conventional osteosarcoma?

Back 49

LUNGS

..then bone.

Front 50

Genetic susceptibility to conventional osteosarcoma?

Back 50

Hereditary retinoblastoma
(gene?)

Li Fraumeni Syndrome
(gene?)

Front 51

Gene for hered retinoblastoma?

Li Fraumeni?

Back 51

LOH @ 13q

TP53 mutations

Front 52

Clinical variants of osteosarcoma?

Morphologic variants?

Back 52

Jaw
Post-radiation
Paget's
Multifocal


Morphologic:
Well-diff intraosseous OS
Telangiectatic
Small cell OS

Front 53

Variant of osteosarcoma?

Back 53

Telangiectatic osteosarcoma
<4% OS

Cystic spaces lined with benign appearing giant cells
Malignant cells within cellular septa

2nd decade.

Purely lytic lesion on imaging

(convtroversy about this entity)

Front 54

Variant of osteosarcoma?

Back 54

Small cell osteosarcoma

Small round blue cells with osteoid production.

Front 55

Major DDx of small cell osteosarcoma?

Back 55

EWINGS!
Both small round blue cells
Both can be CD99+
OS has osteoid but Ewings can have similar looking fibrin
OS will NOT have t(11;22)

Front 56

What to think about in 60y.o. patient with osteosarcoma in the skull?

Back 56

Paget's disease

poor px

long bones, skull, vertebrae, pelvis

Front 57

25F limited knee flexion

Back 57

Parosteal osteosarcoma

70% POSTERIOR distal femur
WRAPAROUND pattern with time

well-formed bony trabeculae in hypocellular stroma. looks like normal bone. stroma has minimal atypia.

50% have cartilage formation...

Great px

Front 58

What it called when parosteal osteosarcoma recurs as high-grade sarcoma?

Back 58

de-differentiated parosteal osteosarcoma

Front 59

10y.o. M diaphyseal lesion, pain.

gross?

Back 59

Ewing sarcoma
xray: moth-eaten appearance and ONION skinning of periosteum
gross: fish flesh
<20y

small round blue cell tumor
Homer Wright rosettes

Front 60

Ewing Sarcoma
IHC?
genetics?
what translocation imparts a more favorable px?

Back 60

CD99 membranous staining (not specific)
can be cytokeratin+
cytoplasm with PAS+ granules

t(11;22)

EWS/FLI1 exon6-exon7 translocation is favorable

Front 61

DDx small round blue cell tumor in bone?
Xray appearance?

Back 61

Ewings/PNET
Primary lymphoma of bone
Met rhabdomyosarcoma
Met neuroblastoma

Also:
Osteomyelitis
Small cell osteosarcoma
Mesenchymal chondrosarcoma
Multiple myeloma
Histiocytosis X / LCH

xray: moth-eaten appearance, permeative pattern
Ewings may have soft tissue mass

Front 62

Asymptomatic metaphyseal lesion in a teenager

Dx?
Imaging?
Px?

Back 62

Non-ossifying fibroma (large), aka
Metaphyseal fibrous defect (when small), aka
Fibroxanthoma

Spindle cell proliferation
STORIFORM pattern
Benign giant cells, foamy histiocytes
Increased mitotic figures
No atypia

Prob due to faulty ossification, not a true neoplasm

Imaging: SOAP BUBBLE. metaphyseal lesion, eccentric, lytic, periph sclerosis

Excellent px, with curettage

Front 63

Same as previous, except older age and in diaphysis or epiphysis?

Back 63

Benign fibrous histiocytoma

Front 64

Knee lesion with moth-eaten appearance on imaging, involving both the proximal tibia and distal femur

Back 64

MFH

Marked pleomorphism, atypical mitoses. Spindled cells with storiform pattern. MNGCs.

Front 65

#1 site of mets in MFH?

Back 65

Lungs

Front 66

variant of osteosarcoma?

Clinical importance?

Back 66

Low-grade central OS, aka well-diff intraosseous OS

-Low-grade spindle cells with osteoid production
-SUBTLE ATYPIA (enlarged, dark, some mits)

these can DEDIFFERENTIATE (20%) to a higher grade, and then metastasize.

Front 67

Destructive lesion distal femur

Back 67

Fibrosarcoma

LOTS OF MITS
HERRINGBONE pattern
~ to MFH (what is the difference??....)

Front 68

Name the fibrous, fibro-histiocytic, and fibro-osseous bone lesions.

Back 68

FIBROUS
-Desmoplastic fibroma of bone
-Fibrosarcoma

FIBRO-HISTIOCYTIC
-Metaphyseal fibrous defect
-Non-ossifying fibroma
-Benign fibrous histiocytoma
-MFH

FIBRO-OSSEOUS
-Fibrous dysplasia
-Osteo-fibrous dysplasia
-FIbrous osteosarcoma

Front 69

Jaw lesion, fibrous and osseous components WITHOUT osteoblastic rimming

VERY hard lesion

Dx?
Radiology?
Forms?

Back 69

Fibrous dysplasia
Ground glass, non-destructive
Monostotic vs polyostotic

histology:
Classic "C"shaped bony spicules in bland spindled stroma.
See spindled cells dissecting the bone.
NO OSTEOBLASTIC RIMMING

Front 70

Fibrous dysplasia
px?
gene?

Back 70

Good px

GNAS1 gene (turns woven bone into lamellar bone)

Front 71

Name the syndrome:
polyostotic fibrous dysplasia
skin pigmentation
endocrine abnormalities

Back 71

McCune Albright Syndrome

Front 72

Name the syndrome:
Polyostotic fibrous dysplasia
Soft tissue myxomas

Back 72

Mazzabrand's syndrome

Front 73

What are the other names for osteofibrous dysplasia?

Back 73

Ossifying fibroma

Campanacci's disease

Front 74

5 year old boy

ANTERIOR TIBIA CORTICAL LESION

Back 74

Osteofibrous dysplasia
= ossifying fibroma
= Campanacci's disease

Front 75

Osteofibrous dysplasia usually resolves but can progress to what tumor?

Back 75

Adamantinoma

Front 76

Anterior tibial lesion 30y M.

Back 76

Adamantinoma
mostly in anterior tibia

BIPHASIC turmor: epithelioid + spindled osteofibrous

Some arise from osteofibrous dysplasia

Can recur.
10% metastasize.

Front 77

Blue nodular plaques on HIV+ patient

Dx?

IHC?

Back 77

Kaposi sarcoma.

-vascular prolif w/ jagged outlines
-extrav RBCs


IHC: HHV8+

Front 78

Painful leg mass

Back 78

Epithelioid hemangioendothelioma
rare
Cords & nests of pink endothelial cells
Don't make vessels, unlike hemangiomas
Usually bland.
CAN METASTASIZE

Front 79

Epithelioid hemangioendothelioma
IHC?
Genetics?

Back 79

CD34, CD31
t(1;3)

Front 80

Leg mass

Back 80

Angiosarcoma

Front 81

Sacral mass x 1 year in adult

Histologic features?

Buzzword for cell type?

Back 81

Chordoma
This is a malignant tumor!
USUALLY WITH LARGE SOFT TISSUE EXTENSION
Lobules of cells separated by fibrous septae
Myxoid matrix
Mild to moderate atypia

PHYSALIFEROUS CELLS! (bubbly cytoplasm)

Front 82

What is important to know about the sampling of chordoma?
How can we differentiate between chondrosarcoma and adenocarcinoma based on IHC?

Back 82

Tranrectal biopsy is CONTRAINDICATED! Tumor is easily spread. Biopsy tract goes through peritoneum!! can seed (like ov ca!)

Chordoma: S100+/ck+/EMA+
CS: + / - / -
Ad: - / + / +

Front 83

20F distal demur

Gross appearance?

Back 83

Giant cell tumor of bone
Usu 20-50y
Benign but very locally aggressive & fast growing

Mononuclear cells & giant cells (NUCLEI OF BOTH ARE THE SAME)
Mononuclear cells have SCANT cytoplasm

Grossly, red-black with hemorrhage

Front 84

GCT bone
Site?
DDx?

Back 84

Ends of long bones (Epiphysis)
(Distal femur, prox tibia & humerus)

DDx:
Chondroblastoma (mononuclear cells have abundant eosinophilic cytoplasm; sclerotic rim; usu younger age <20)

Front 85

17Y with eccentric lytic lesion distal femur. Multiple fluid levels on imaging.

Back 85

Aneurysmal bone cyst
Benign cystic lesion of bone
usually <20y
Primary: 70%. Bland fibroblasts and MNGCs, multilocular
Secondary: occurs in GCT, OB, CB, FD
Can look like telangiectatic OS

Front 86

Genetics of ABC?

Back 86

Chrom 17

Front 87

Skull lesion 20y.o.

Back 87

Langerhans cell histiocytosis

Reniform nuclei
Nuclear GROOVES
Abundant eos
Giant cells
Mitoses

Front 88

LCH
IHC?
EM?

Back 88

CD1a, S100, Langerin

Birbeck granules on EM

Front 89

Radiology: Bilateral symmetric sclerosis of the medullary cavity with epiphyseal SPARING

Back 89

Erdheim Chester Disease

Infiltration of the skeleton and viscera by lipid-laden histiocytes

Very rare

Poor px

Front 90

Syndrome: Multifocal lytic bone lesions, exophthalmos, diabetes insipidus

Back 90

Hand-Schuller-Christian Disease
Infants

Multifocal LCH
DI from infilt of pituitary

Front 91

often fatal disease of young children that is marked by proliferation of Langerhans cells and is characterized especially by fever, anemia, hepatosplenomegaly, and eczematous skin rash

Back 91

Letterer-Siwe Disease

Front 92

Radiolucent bone lesion in patient with hyperparathyroidism

Back 92

Brown tumor of bone
NOT a neoplasm
Osteoclastic giant cells and fibrogenic stroma

(GCT of bone lacks fibrogenic stroma)

Front 93

Syndrome of multiple Brown tumors?

Back 93

Osteitis fibrosa cystica
aka von recklinghausen disease of bone

Front 94

Causes of osteitis fibrosa cystica?

Back 94

Advanced hyperparathyroidism

-PTH adenoma (80%)
- Hereditary (10%) (MEN1)
- PTH carcinoma
- Renal osteodystrophy

First affects bones of fingers, face, ribs, pelvis

Front 95

Finger lesion in 15y.o.

Dx?
DDx?

Back 95

BPOP
aka Nora's lesion

Rare. Hands & feet. Rapid growth. Often misdiagnosed.

Cellular cartilage, bizarre fibroblasts, disorganized bone formation. LACK of atypia.

DDx:
Chondrosarcoma
Fibrosarcoma
LG Parosteal osteosarcoma
Conventional Osteosarcoma