Chapter 26: Bone Tumors and Tumor-Like Lesions Flashcards

1
Q

How does osteoid osteoma differ from osteoblastoma in terms of size and bone predilection?

A
  • Osteoid osteoma: <2cm in diameter; predilection for appendicular skeleton (50% involve femur or tibia) arising in cortex
  • Osteoblastoma: are >2cm and involve posterior spine (laminae and pedicles)
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2
Q

How does the pain and responsiveness to aspirin/NSAIDs differ between osteoid osteoma and osteoblastoma?

A
  • Both are painful, and the pain is typically worse at night
  • Osteoid osteoma DOES respond to aspirin/NSAIDs
  • Osteoblastoma DOES NOT respond!
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3
Q

What is a radiographic clue for osteoid osteoma?

A
  • Thick rind of reactive cortical bone; surrounding a nidus
  • Osteoid osteomas elicit formaion of a tremendous amount of reactive bone
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4
Q

Describe the characteristic morphology of osteoid osteoma and osteoblastoma?

A

Haphazardly interconnecting trabeculae of woven bone that are rimmed by prominent osteoblasts

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5
Q

Which histologic features of osteoid osteomas and osteoblastomas help to distinguish them from osteosarcomas?

A

Relatively small size, well-defined margins, and benign cytologic features of the neoplastic osteoblasts

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6
Q

What is the bimodal age of distribution seen with osteosarcoma; which sex is most affected?

A
  • 75% occur in pt’s <20 y/o
  • 2nd peak in older adults (>65 y/o), frequently in assoc. w/ Paget disease, bone infarcts, and prior radiation
  • Men more commonly affected
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7
Q

Which part of bones do osteosarcomas arise in and which bones are most often affected?

A
  • Arise in metaphyseal region of long bones of extremities
  • Almost 50% occur about the knee (i.e., distal femur or prox. tibia)
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8
Q

How do osteosarcomas typically present?

A
  • Painful, progressively enlarging mass
  • Sometimes sudden fracture is the 1st sx
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9
Q

What are the characteristic X-ray findings with osteosarcoma?

A
  • Large destructive, mixed lytic and blastic mass w/ infiltrative margins
  • Frequently breaks thru periosteum, resulting in reactive periosteal bone formation –> Codman triangle = elevated periosteum
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10
Q

Germline mutation in what gene are associated with a 1000-fold increased risk for osteosarcoma; occurence in sporadic tumors?

A
  • Germline mutation in RB = 1000-fold ↑ risk
  • This mutation is present in up to 70% of sporadic tumors
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11
Q

Li-Fraumeni syndrome is associated with what germline mutation; have an increased risk for what MSK pathology?

A
  • Germline TP53 mutations
  • Greatly ↑ risk of osteosarcoma
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12
Q

Why do osteosarcomas peak in incidence around the time of the adolescent growth spurt and how does this relate to their location?

A
  • Occur most frequently in the region of the growth plate in bones with the fastest growth
  • The ↑ proliferation at these sites may predispose to mutations
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13
Q

Which morphological feature of osteosarcomas is diagnostic; what is seen?

A
  • Formation of bone by the tumor cells = diagnostic
  • Neoplastic bone usually has fine, lace-like architecture but also may be deposited in broad sheets of primitive trabeculae
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14
Q

When malignant cartilage is abundant in osteosarcomas they are referred to as what?

A

Chondroblastic osteosarcoma

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15
Q

Osteosarcomas frequently metastasize via which route and to where?

A

Hematogenously to the lungs, bone, and brain

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16
Q

How is osteoid osteoma vs. osteoblastoma treated?

A
  • Osteoid osteoma is frequently treated w/ radiofrequency ablation
  • Osteoblastoma is usually curetted or excised en bloc
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17
Q

What is the multi-modality approach to tx of osteosarcomas?

A
  • Neoadjuvant chemotherapy, which is given under the assumption that all pt’s have occult metastases at time of dx
  • Followed by surgery
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18
Q

What is the most common benign bone tumor?

A

Osteochondroma (aka exostosis)

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19
Q

Majority (85%) of osteochondroma arise how and the remainder are associated with what herediatry disease?

A
  • 85% are solitary; arise in early adulthood w/ men 3x > women
  • Remainder assoc. w/ multiple hereditary exostosis syndrome, an autosomal dominant hereditary disease
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20
Q

Where in bone do osteochondromas arise and which bones most often affected?

A
  • Only bones of endochondral origin and arise from the metaphysis near the growth plate
  • Long tubular bones, especially near knee
  • Occasionally seen in bones of pelvis, scapula,andribs
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21
Q

Hereditary osteochondroma (exostoses) and some sporadic types are assoc. w/ what mutations?

A
  • Hereditary = germline loss-of-function EXT1 or EXT2
  • Sporadic = ↓ expression of EXT1 or EXT2
  • These genes encode enzymes that synthesize heparin sulfate gylcosaminoglycans
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22
Q

What is the characteristic morphology and growth pattern of osteochondromas?

A
  • Are sessile or pedunculated w/ cap composed of benign hyaline cartilage varying in thickness
  • Cortex of newly formed stalk merges w/ cortex of the host bone, so that medullary cavity of the osteochondroma and bone from which it arises are in continuity
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23
Q

What is a complication of osteochondroma that is more often seen in those assoc. w/ multiple hereditary exostosis?

A

Progression to chondrosarcoma

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24
Q

What are chondromas and what are they known as if they arise in the medullary cavity vs. surface of bone?

A
  • Benign tumors of hyaline cartilage
  • In medullary cavity = enchondromas
  • Surface of bone = juxtacortical or subperiosteal chondromas
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25
Q

Which age group are enchondromas most often seen in and which bones most often affected?

A
  • 20-50 y/o
  • Appear as solitary metaphyseal lesions of tubular bones of the hands and feet
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26
Q

Which 2 non-hereditary disorders are characterized by multiple enchondromas; characteristics of each?

A
  • Ollier syndrome = multiple enchondromas
  • Mafucci syndrome = multiple enchondromas + angiomas –> ↑ risk of chondrosarcoma and other malignancies
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27
Q

Which mutations have been identified in the chondrocytes of syndromic and solitary enchondromas?

A

Heterozygous mutations in the IDH1 and IDH2 genes

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28
Q

What is the size and characteristic morphology of enchondromas; how does this differ in the non-hereditary disorders Ollier and Maffucci syndrome?

A
  • Usually <3cm and are gray-blue and translucent
  • Well-circumscribed nodules of hyaline cartilage containing benign chondrocytes
  • Periphery may ossify and center can calcify and infarct
  • Ollier and Maffucci: ↑ cellularity and atypia
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29
Q

Which malignancies are those with Mafucci Syndrome at increased risk of developing?

A

Chondrosarcoma + ovarian carcinomas and brain gliomas

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30
Q

Which age group is Chondrosarcoma most often seen in and it commonly arises in which bones?

A
  • Usually 40 y/o + with Men 2x > female
  • Axial skeleton: pelvis, shoulder, and ribs
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31
Q

A majority of chondrosarcomas arise de novo, but some arise from which 2 pre-existing tumors?

A

Osteochondroma or enchondromas

32
Q

Chondrosarcomas arising in associated with syndromes such as multiple osteochondroma syndrome or those that are chondromatosis-related have which mutations?

A
  • Multiple osteochondroma syndrome: mutations in EXT genes
  • Chondromatosis-related: IDH1 and IDH2
33
Q

Sporadic chondrosarcomas may have what mutations?

A
  • IDH1 and IDH2 mutations
  • Silencing of the CDKN2A tumor suppressor gene by DNA methylation
34
Q

Which variant of chondrosarcoma is characterized as being composed of islands of well-differentiated hyaline cartilage surrounded by sheets of small round cells, which can mimic Ewing Sarcoma?

A

Mesenchymal chondrosarcoma

35
Q

What is characteristically seen on radiographic imaging of chondrosarcoma?

A

Calcified matrix appears as foci of flocculent densities

36
Q

What is the gross morphology of chondrosarcomas?

A

Large bulky tumors made up of nodules of glistening gray-white, translucent cartilage but matrix is often gelatinous or myxoid

37
Q

How are chondrosarcomas graded and what is unique about this grading?

A
  • Assigned a grade from 1 to 3
  • Direct correlation between grade and behavior
38
Q

What is the behavior of chondrosarcomas and how may they metastasize and to where?

A
  • Invade locally, painful enlarging mass.
  • 70% of grade 3 spread hematogenously, especially to lungs
39
Q

What is the 5-year survival for grade 1 vs. grade 3 chondrosarcomas and how are they tx?

A
  • Grade 1 have 5-year of 80-90%; drops to 43% for grade 3
  • Tx is by wide surgical excision
40
Q

Ewing Sarcoma is a malignant bone tumor characterized by what?

A

Primitive round cells without obvious differentiation

41
Q

Ewing sarcoma is most often seen in which age group and has a predilection for which ethnicity?

A
  • 80% arise in pt’s <20 y/o with slightly more males affected
  • Striking predilection for whites, while blacks/asians rarely affected
42
Q

Where in bones does Ewing Sarcoma arise and which bones are most often affected?

A
  • Arise in the diaphysis of long tubular bones; in the medullary cavity
  • Especially the femur and flat bones of the pelvis
43
Q

How does Ewing Sarcoma typically present?

A
  • Painful enlargin mass; frequently tender, warm, and swollen
  • Some have systemic findings that mimic infection –> including fever, ↑ ESR, anemia, and leukocytosis!
44
Q

Plain radiographs of Ewing Sarcoma will show what; what is characteristic of the periosteal rxn of these tumors?

A
  • Destructive lytic tumor w/ permeative margins that extends into surrounding soft tissues
  • Produces layers of reactive bone deposited in an onion-skin like fashion
45
Q

Which translocation and fusion gene product is characteristic of Ewing Sarcoma?

A

t(11;22) –> EWS-FL11 gene

46
Q

What does the presence of Homer-Wright rosettes in Ewing Sarcomas indicate?

A

A greater degree of neuroectodermal differentiation

47
Q

What is the treatment and 5-year survival with Ewing Sarcomas?

A
  • Tx w/ neoadjuvant chemotherapy followed by surgical excision with or without radiation
  • 5-year survival of 75% and long-term cure in 50%
48
Q

What is an important prognostic finding associated with tx of Ewing Sarcoma?

A

Amount of chemotherapy-induced necrosis

49
Q

Which bone tumor composed of multinucleated osteoclast-type giant cells is benign, but locally aggressive?

A

Giant Cell Tumor

50
Q

The neoplastic cells of Giant Cell Tumors express high levels of what?

A

RANKL –> promoting proliferation and differentiation of osteoclasts

51
Q

Where do Giant Cell Tumors most often arise?

A
  • Epiphyses, may extend into metaphysis
  • Majority around knee (distal femur and prox. tibia)
52
Q

Why are giant cell tumors so highly destructive?

A

RANKL from neoplastic cells with loss of feedback btw osteoblasts and osteoclasts that normally regulates process of bone remodeling

53
Q

What is the treatment, recurrence rate and prognosis for Giant Cell Tumors?

A
  • Tx with curettage —> 40-60% will recur locally
  • 4% will metastasize to lung, may regress and seldom fatal
54
Q

Aneurysmal bone cyst (ABC) frequenlty arises in which bones?

A
  • Metaphysis of long bones
  • Posterior elements of vertebral bodies
55
Q

Signs and sx’s of Aneurysmal bone cyst (ABC)?

A
  • Most common = pain + swelling
  • If involves vertebrae, can compress nerves –> neurologic sx’s
56
Q

How do aneurysmal bone cyst (ABC) appear radiographically?

A
  • Eccentric, expansile lesion w/ well-defined margins
  • Most being completely lytic, often w/ thin shell of reactive bone at the periphery
57
Q

CT and MRI of aneurysmal bone cyst (ABC) may demonstrate what?

A

Internal septa and characteristic fluid-fluid levels

58
Q

The spindle cells of aneurysmal bone cyst (ABC) frequently demonstrate which mutations?

A

Cr. 17p13 rearrangement —> USP6 overexpression

59
Q

Unusually dense calcified matrix called “blue bone” is seen in some cases of what bone tumor?

A

Aneurysmal bone cyst (ABC)

60
Q

Morphology of aneurysmal bone cyst (ABC)?

A
  • Multiple blood-filled cystic spaces separatd by thin, tan-white septa
  • Septa are composed of plump, uniform fibroblasts, multinucleated osteolcast-like giant cells, and reactive woven bone
61
Q

What are fibrous cortical defects (aka metaphyseal fibrous defects); where and in whom do they arise; defining characteristics?

A
  • Extemely common arising in 30-50% of children >2 y/o
  • Arise eccentrically in metaphysis of distal femur and prox. tibia
  • Almost 1/2 are bilateral** or **multiple
62
Q

How does fibrous cortical defect differ from nonossifying fibroma?

A
  • Fibrous cortical defects: typically small, about 0.5cm in diameter
  • Nonossifying fibroma: larger, up to 5-6cm in size; usually not detected until adolescence or adulthood
63
Q

What is the characteristic morphology of the fibroblasts and macrophages seen in both fibrous cortical defect and nonossifying fibroma; what other finding is commonly present?

A
  • Cytologically bland fibroblasts arranged in storiform (pin-wheel) pattern***
  • Macrophages may take form of clustered cells w/ foamy cytoplasm or multinucleated giant cells
  • Hemosiderin is commonly present
64
Q

What are the characteristic findings on radiograph of fibrous cortical defects and nonossifying fibromas?

A

Eccentric lobulated radiolucency surrounded by thin rim of sclerosis

65
Q

What is the typical behavior and prognosis of fibrous cortical defects?

A
  • Most have limited growth potential and undergo spontaneous resolution within several years
  • Few progressively enlarge –> nonossifying fibroma may present w/ pathologic fracture or require biopy and curettage to exclude other tumor types
66
Q

What is fibrous dysplasia and what has it been likened to?

A
  • Benign tumor likened to localized developmental arrest
  • ALL components of normal bone present, but they do not differentiate into mature structures
67
Q

Which 2 syndromes are associated with fibrous dysplasia and what is seen in each?

A
  • Mazabraund syndrome: fibrous dysplasia (usually polyostotic) + soft tissue myxomas
  • McCune-Albright disease: unilateral bone lesions w/ café-au-lait skin pigmentations + endocrine abnormalities; esp. precocious puberty
68
Q

Fibrous dysplasia is due to mutations in what; what other pathology is this gene mutated in?

A
  • Somatic gain-of-function mutation during development in GNAS1
  • Leads to constitutively active GS-protein
  • This gene is also mutated in pituitary adenomas
69
Q

Characteristic morphology of fibrous dysplasia includes what?

A

Curvilinear shapes of the trabeculae of woven bone mimic Chinese characters and bone lacks prominent osteoblastic rimming

70
Q

Monostotic fibrous dysplasia most often occur when and affects which bone; presenting sx’s?

A
  • Early adolescence and equally in boys and girls; typically asymptomatic
  • The femur, tibia, ribs, jawbones, calvarium, and humerus = most commonly affected
71
Q

Monostotic fibrous dysplasia is seen on radiographic imaging as what?

A

Ground glass appearance and well-defined margins

72
Q

Polyostotic fibrous dysplasia appears when, affects which bones, and produces what problems?

A
  • Slightly earlier than the monostotic form
  • Femur > skull > tibia > humerus > ribs > fibula > radius > ulna > mandible > vertebrae
  • Propensity to involve shoudler and pelvic girdles –> severe, progressive disease w/ crippling deformities and fractures
73
Q

What is a rare complication of polyostotic fibrous dysplasia?

A

Malignant transformation —> sarcoma

74
Q

Which cancers in adult most frequently metastasize to the bone?

A

Prostate + breast + kidney + lung

75
Q

Which cancers in children most frequently metastasize to the bone?

A

Neuroblastoma + Wilms tumor + Osteosarcoma + Ewing sarcoma + Rhabdomyosarcoma

76
Q

Skeletal metastases are typically multifocal, but carcinomas from which 2 sites may present with solitary lesions?

A

Kidney and thyroid carcinomas

77
Q

Metastases from which site produces a blastic (bone forming) pattern?

A

Prostatic adenocarcinoma