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Flashcards in Bone Tumors Deck (71)

Bone mets

(a) single or multifocal
(b) axial or appendicular skeleton
(c) distal or proximal
(d) location on the bone

Bone mets

(a) typically multifocal- will often see mets elsewhere
(b,c) In the proximal axial skeleton- proximal femur and humerus
(d) often along the metaphyseal junction, white lesions interrupting the medullary cavity


Differentiate lytic vs. blastic lesions

Which type are
(a) prostate cancer mets
(b) thyroid cancer mets

Radiologic appearance
-lytic lesions = radiolucent (black)
-blastic lesions = radiodense (white)

(a) Prostate mets usually blastic (white)
(b) Thyroid mets usually lytic (white)


Where are the majority of bone mets from in adults? (3 places)

Prostate, breast, lung


Where are the majority of bone mets from in children?

Almost all are going to be neuroblastomas

-then minority will be Wilm's tumor and osteosarcoma


Are most primary bone tumors benign or malignant?

Benign far outweigh the malignant


What are the three benign bone-forming tumors

(a) What type of bone do they form

3 benign bone-forming primary bone tumors = osteoma, osteoid osteoma, osteoblastoma

(a) produce osteoid- unmineralized bone


Which benign bone-forming tumor:

Is an exophytic mass usually growing out of the skull?



Which benign bone-forming tumor:

Cannot be distinguished from normal bone microscopically



Which benign bone-forming tumor:

Is treated by local excision

Osteoid osteoma and osteoblastomas both treated by local excision

-both as seen in young age ( F (2:1)


Which benign bone-forming tumor:

May be found with GI polyps and skin findings as part of a syndrome

Multiple osteomas + GI polyps + skin and soft tissue tumors = Gardner's syndrome = autosomally dominant genetic syndrome

-if not as part of this syndrome osteomas are completely benign and clinically insignificant!


Osteoid ostoma vs. osteoblastoma

(a) Major distinguishing feature
(b) Most common location
(c) Type of pain
(d) Response to aspirin

Major distinguishing feature = size

Osteoid osteoma
(a) Less than 2 cm
(b) Appendicular skeleton
(c) Sharp nocturnal pain
(d) Relieved by aspirin

(a) 2 cm, can be huge
(b) axial skeleton (vertebral column)
(c) Dull pain
(d) Not responsive to aspirin



Histological characteristic of osteoid osteoma and osteoblastoma

-similar to woven bone but stroma is extra vascularized


How osteoblastomas differ histologically from osteosarcoma

Osteoblastomas = benign cytology and defined margins


(a) 1st
(b) 2nd
(c) 3rd

Most common primary bone cancers

Primary bone cancers, most common

(a) 1st = myeloma
(b) 2nd = osteosarcoma
(c) 3rd = chondrosarcoma



(a) Most common age group
(b) Most common location
(c) Can be secondary to what other disease

Osteosarcoma = malignant bone-forming tumor

(a) Mostly in teens
(b) > 50% around the knee, predilection from metaphysis of long bones
(c) Can be secondary to Paget's disease



(a) Gross appearance
(b) Significance of Codman's triangle


(a) Grossly: large destructive lesion destroying the cortex and extending in soft tissue
(b) Codman's triangle = radiographic finding of the periosteal surface being lifted up as the bone permeates underneath, showing that the tumor has broken thru the cortex and periosteal membrane


Best predictor of prognosis for

(a) Osteosarcoma
(b) Chondrosarcoma

Predictor of prognosis

(a) Osteosarcoma- best prognostic indicator is response to chemo
-post-chemo tumor necrosis of > 90% has the best prognosis

(b) Chondrosarcoma- best prognostic indicator is grade
-grade = histologically how similar the cells look like normal cartilage


Histological findings of osteosarcoma

Pink lace-like osteoid (no inorganic matrix)
-production of both malignant bone and malignant (abnormal) cartilage tissue
-cells are large, dark, pleomorphic w/ high mitotic activity


Which two bone cancers are exostosis

Exostosis meaning they come out of the bone

= osteochondromas (stalk w/ cartilage cap)
= osteoma (just a little bump of bone)


Describe the morphology of an osteochondroma

(a) Differentiate osteochondromas from osteoma

"cauliflower" like lesion w/ a bony stalk growing out of the metaphysis and cartilaginous cap

(a) Osteochondromas have both bony stalk and cartilaginous cap, while osteoma just have a litte bony protuberance


What is special about osteochondroma in a skull bone


Osteochondromas ONLY occur on bones that form by endochondral ossification (so long bones)


Distinguish the difference in metastatic potential btwn osteochondromas and osteomas

Osteochondromas have a small malignant potential- rare but possible malignant transformation into chondrosarcomas

While osteomas DO NOT malignantly transform into osteosarcomas


When do osteochondromas stop growing?

It's like an irregular growth plate so the osteochondroma stops growing when skeletal maturity is reached


What is a chondroma?

Benign tumor of hyaline cartilage

-so different from osteochondroma b/c there's no 'osteo' => no bony component



(a) Radiologic appearance
(b) Gross appearance


(a) Radiolgoically: popcorn shaped lucent lesions in appendicular skeleton
(b) Grossly- slate blue (cartilage is slate blue/whiteish color) circumscribed lobulated nodules that do not infiltrate soft tissue


Which tumor is associated w/ Maffucci's syndrome

Rare syndrome (w/e) but associated w/ large chondromas

-so chondromas are not clinically relevate unless associated w/ bone deformities + hemangiomas = Maffucci's


What are chondrosarcomas?

(a) Radiologic appearance
(b) Age group
(c) Common areas

Chondrosarcoma = malignant neoplasm producing cartilaginous matrix

(a) Radiologically: "soap bubble" appearance, think circulatr like the isogenous groups that cartilage grows in
(b) Always > 40
-many bone tumors cna present w/ clinically enlarging mass, but isn't a chondrosarcoma if pt is


How are most chondrosarcomas treated?

Most (luckily) chondrosarcomas are low grade and indolent => treatable by large resection


Differentiate Ewing's Sarcoma and PNET

(a) Age group
(b) Prognosis

Ewing's sarcoma and PNET have identical genetic translocations, but they represent a spectrum from little neural differentiation (Ewing's) to more neural differentiation (PNET)

PNET = primitive neuroectodermal tumor

(a) Both seen in pts


What is the primary malignant small round blue cell tumor of bone?

Ewing's sarcoma/PNET


What is the genetic translocation responsible for Ewing's sarcoma?

(a) What fusion gene is produced

t (11;22) which creates a EWS-FLI1 fusion gene that codes for MIC2

(a) MIC2 = very potent transcription factor that induces proliferation


Ewing's sarcoma/PNET

(a) characteristic radiologic finding
(b) characteristic histological finding
(c) immunostains positive for what?

Ewing's sarcoma/PNET

(a) Radiologically: onion skin reaction of the bone
(b) Histo: pseudorosettes = small round blue cells encircling neutropil material
(c) Characteristically immunostain (+) for CD99


Are giant cell tumors of bone benign or malignant?

Kinda are on the fence: have characteristics of both

-are usually benign (dont met) but can be very locally aggressive)
-dont go thru the cortex but cross the growth plate


Histologic appearance of giant cell tumors of bone

Abundance of multinucleated osteoclast-like giant cells (hence it's name...)


Give some examples of soft tissue

Mesodermally derived supporting tissues
-adipose tissue
-smooth and skeletal muscle
-blood and lymphatic vessels
-peripheral nerves

Everything else: not cartilage, CNS, hematopoetic, and lymphod


Distinguish myofibroblasts and fibroblasts

Myofibroblasts are fibroblasts that have smooth muscle component
ex: found around mammary ducts: contract and push milk out of ducts


What is the prefix for tumors arising from the following tissues

(a) skeletal muscle
(b) adipose tissue
(c) smooth muscle
(d) vessels
(e) fibroblasts/fibrous tissues

Tumors arising from the following tissues

(a) Rhabdo = skeletal muscle
(b) Lipo = adipose tissue
(c) Leio = smooth muscle
(d) Angio = vessels
(e) Fibro = fibrous tissue


What is the best predictor of prognosis for soft tissue malignancies?

Grade- determined by cell differentiation

-more poorly differentiated = looks the least like normal tissue = higher grade = worse prognosis


Are benign or malignant soft tissue tumors more common?

(a) Exception

Benign outnumber malignant soft tissue tumors from 100:1
ex: lipomas way outnumber liposarcomas

(a) EXCEPT for skeletal muscle tumors- rhabdomyeosarcomas (malignant) way more common than rhabdosarcoma (benign)


Which soft tissue tumors are extremely rare yet very lethal

Smooth muscle tumors- extremely rare, but account for a larger in-proportionate amount of cancer deaths


How do most soft tissue tumors spread?

(a) Exception

Most metastasis of soft tissue tumors are by hematogenous route

(a) Exception = synovial sarcoma, which metastasizes to lymph nodes


What is the most common soft tissue tumor of adults?

Lipomas = benign tumor of fat



(a) gross anatomy
(b) treatment
(c) clinical presentation
(d) Histologic findings

Lipomas = benign tumor of fat

(a) Grossly: encapsulated yellow fat
(b) Treated by excision
(c) Usually asymptomatic: mobile, slow growing subcutaneous mass
(d) Histologically looks like normal mature white fat: mature adipocytes, no pelomorphism


How to pathologically differentiate lipoma and liposarcoma

(a) Genetically
(b) Histologically

Lipoma (benign) vs. liposarcoma (malignant) tumor of fat

(a) Liposarcoma = positive for MDM2 amplification, while lipoma is negative for MDM2 amplification

(b) Normal appearing white mature fat = lipoma. Lipoblast (immature, mimicking fetal fat: multivacuolated, malignant adipocyte) = liposarcoma


Which fibroblastic lesion is a pseudosarcoma

Nodular fasciitis- very commonly confused as sarcoma (malignant tumor), while it is really just a transient clonal proliferation of fibroblasts


Describe the typical pt for nodular fasciitis

(a) Disease mechanism
(b) Treatment

Nodular fasciitis = kind/young adult following trauma, rapid growth, painful

(a) Transient clonal proliferation of fibroblasts
(b) Excision is usually curative


Ddx for rapidly enlarging tissue mass in a child

Sarcoma (malignant), nodular fasciitis (benign)


Location of nodular fasciitis

Nodular fasciitis location = in the fascia under the subcutis (so it goes epidermis --> dermis --> subcutis --> fascia (where the fibroblast proliferation occurs) --> underlying musculature


Histological findings of nodular fasciitis

Nodular fasciitis histologically:

Reactive proliferating fibroblasts producing tons of collagen


Blunt trauma to soft tissue that damages both muscle and the periosteum

= Myositis Ossificans
-bony equivalent to nodular fasciitis

Reactive fibroblast proliferation w/ surrounding reactive bone formation (calcification)
-soft center (fibroblast proliferation resembling nodular fasciitis) + surrounding egg shell calcification


Name a genetic condition that is involves both bone and soft tissue tumors

Gardner's syndrome
-fibromatosis of the mesentery (soft tissue)
-osteomas of bone (bone involvement)
-adenomas and colon cancer (get colonoscopies for pts w/ fibromatosis + osteomas)

due to mutation in APC gene


Describe the mechanism of the genetic abnormality seen in Gardner's syndrome

Gardner's syndrome = APC mutation which makes APC no longer able to bind (and inactivate) beta-catenin => permanently activated beta-catenin tf => upregulated WNT signaling pathway

-loss of break on WNT signaling pathway => uncontrolled proliferation


What is the most common sarcoma?

Undifferentiated pleomorphic sarcoma = malignant fibrous histocytoma

= dx of exclusion for sarcomas that can't be more precisely categorized


Undifferentiated pleomorphic sarcomas

(a) Another name
(b) Age group
(c) Grade
(d) Histologic features

Undifferentiated pleomorphic sarcomas
(a) Malignant Fibrous Histiocytoma
(b) Older pts (not seen in children/young adults)
(c) Usually high grade
(d) Histologically: tons of mitotic figures, anaplastic cells whose cell of origin can't be determined


Biphasic sarcoma

= Synovial sarcoma
-unclear cell of origin

Biphasic b/c have uniform spindle cells (high N:C ratio) simultaneously w/ gland-forming epithelial cell appearance



(a) Disease
(b) Fusion protein and fxn

Translocation btwn x and chrom 18 = indicative of synovial sarcoma (a)

(b) Fusion protein found promotes fibroblast proliferation


How likely are the following to malignantly transform?

(a) Adenomas
(b) Hemangiomas
(c) Osteomas
(d) Chondromas
(e) Lipomas

Risk of malignant transformation

(a) Pretty high- adenomas of epithelium can definitely transform into their adenocarcinoma counterparts
(b) Hemangiomas don't transform into angiosarcomas
(c) Osteomas don't transform into osteosarcomas
(d) Chondromas rarely do, but can, become chondrosarcomas
(e) Lipomas do not become liposarcomas

-take away point = soft tissues don't malignantly transform


After a radial mastectomy a women has chronic lymphedema, what soft tissue tumor is she at risk for?

Chronic lymphedema increases risk for angiosarcoma (malignant endothelial tumor of BV lining)


What is fibrous dysplasia?

(a) Histologic features

Fibrous dysplasia is not a cancer! It's when bony trabeculae proliferate instead of maturing = developmental arrest of trabeculae = immature bony trabeculae that never matures

(a) Histologically: see no hematopoeitic marrow, instead just see medullary compartment filled w/ scar-like fibroblastic proliferation


Distinguish monostotic and polyostotic fibrous dysplasia

(a) which is more common
(b) clinical features
(c) location

2 types of fibrous dysplasia

(a) Much more common, 70% of cases
(b) often asymptomatic, incidental finding


What to worry about if you see polyostotic fibrous dysplasia + precocious puberty

Albright-McCune syndrome = polyostic fibrous dysplasia + precocious puberty (endocrinopathy) + skin pigmentation


Unicameral vs. Aneurysmal Bone Cyst

(a) Age group
(b) Appearance on Xray
(c) Clinical features
(d) Treatment

Unicameral bone cyst = simple cyst


Aneurysmal bone cyst

(a) Histologically
(b) Pathologically

Aneurysmal bone cyst

(a) Histologically: spindled fiborblastic cells, multinucleated giant cells, thin strands of reactive bone and osteoid
(b) Pathologically: blood filled multilocular cyst w/ peripheral thin shell of reactive periosteum


Giant cell tumors

(a) of bone
(b) of the tendon sheath
(c) of the synovium

Giant cell tumors

(a) Giant cell tumors of bone
(b) Giant cell tumors of the tendon sheath
(c) of the synovium = PVNS = pigmented villonodular tenosynovitis


What is Paget's disease?

Paget's disease = osteitis deformans
Focal disorder (so not ubiquitous like osteoporosis) of bone metabolism in the aging skeleton

Osteoclast abnormality- accelerate bone turnover and abnormal remodeling


Lab findings in Paget's disease

Elevated alkaline phosphatase
Normal calcium and phosphate


Which bones are most affected in Paget's disease

Most commonly affected = pelvis, femur, lower lumbar vertebrae


What is the most common manifestation of Paget's disease?

(a) Most common symptom

Paget's disease is often asymptomatic => doesn't present b/c of pain. First manifestation is usually elevated alk phos

(a) Most common symptom = bone pain


How can Paget's disease be diagnosed?

Characteristic Xray findings
-elevated alkphos (reflecting increased bone turnover)


Pt population for Paget's disease

> 55 yoa, happens in aging bone


Why do bones often look thicker in Paget's disease

Increased turnover, accelerated bone turnover and abnormal remodeling