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Self-quiz on Tumor and tumor-like processes
What is the most common source of osteoblastic metastatic carcinoma in adult females?

--70% are from Breast cancer, also common in women: thyroid, kidney, uterus
--in men: 60% from prostate, lung 25%

What fraction of mets are lytic vs blastic?
--75% lytic, 15% blastic, 10% mixed
--"blow out" pattern rare, suggests renal or thyroid primary

How can you begin to discriminate metastases from primary lesions?
--mets are most common, usu 2-4 cm in size and several of them
--primaries more likely toshow expansion of bone, periosteal response, to be over 10cm with a soft tissue mass, and to be solitary



What benign lesion can cross the growth plate, from the metaphysis to the epiphysis of a bone?
--an aneurysmal bone cyst

List the three common causes of solitary sclerotic vertebral body, aka Ivory Vertebra:
1-Hodgkin’s Lymphoma (anterior body scalloping)
2-Osteoblastic metastastic → ** Most Common
3-Paget’s Disease (cortical thickening and expansion)
Hint: Can’t differentiate end plates

What part of a bone do most lesions appear in, and why?
--the metaphysis, because it is most metabolically active and vascular

What kinds of lesions are found in the diaphysis (shaft) of a bone?
--mostly marrow related or "round cell" tumors
--multiple myeloma
--Ewing's sarcoma
--Non-Hodgkin's lymphoma



Which lesions can bridge from metaphysis to diaphysis?
--chondrosarcoma
--osteosarcoma
--multiple myeloma
--osteoid osteoma
--NOF = non-ossifying fibroma
--chondromyxoid fibroa

If you see a long lesion in a long bone, what should you suspect?
--fibrous dysplasia

Is it common to find a tumor involving a joint?
--NO. think arthritis first if joints are involved.

What are the most common tumors in bone, overall?
--mets are 25x more common than primary malignancis of bone
--70% of malignant bone tumors are mets
--80% come from breast, prostate, lung and kidney
--mets are the most common cause of a missing pedicle, ddx agenesis ("winking owl sign")

What are the most common primary sources for cancerous mets to bone?
--breast, prostate, lung, kidney, thyroid, and bowel

Where do mets go in the skeleton?
--axial skeleton (spine, 12% to pelvis, 28% to ribs & sternum), skull, 10% proximal extremities, usu proxial femur & humerus
--rarely distal to knee or elbow
--if mets are acral (past knee/elbow) then most likely originated in lung

Is multiple myeloma more common in the vertebral body or neural arch?
--vertebral body
--single lytic lesion is termed a plasmacytoma (solitary myeloma)


What malignancy demonstrates as a "cold" bone scan?
--multiple myeloma--may have bone scan with no signs at all
--this is how you DDX multiple myeloma from mets which are hot


Which is the most dense primary malignant bone tumor?
??? OSTEOSARC? osteoid osteoma?? don't know.

What are the most COMMON primary malignant bone tumors? (MOCE common, in order)
--Multiple myeloma (50-70 yo) (27% of biopsied bone tumors) M:F = 2:1
--Osteosarcoma (10-25)
--Chondrosarcoma (40-60)
--Ewing’s (10-25)

What is the common age range of primary osteosarcoma?
75% occur in 10-25yo; in older patients dt malignant degeneration of a benign process




What is the difference between sunburst and onion skin appearance?
--SUNBURST periosteal response = aka spiculated = divergent, with rays
--characteristic of osteosarcoma
--spicules of bone more irregular/coarser than hair-on-end pattern

--ONIONSKIN = lamellated, with layers, no good images available this moment
--implies a more aggressive process but is encountered in both benign and malignant disease
--most characteristic of Ewing’s tumor (Ewing’s sarcoma) but mb found in osteosarcoma, acute, osteomyelitis, stress fractures and eosinophilic granuloma in very young patients
--HAIR ON END PATTERN = uniform, fine, parallel linear shadows perpendicular to cortex
--characteristic of Ewing’s sarcoma

Which part of the bone is commonly involved in osteosarcoma?
--metaphysis of long bone, esp distal femur, proximal tibia, proximal humerus
--around the knee is most common

What is Codman’s triangle?
--wedge of regular periosteal elevation on either side of the lesion
--not good biopsy site, is made up of periosteal reaction and free of tumor cells
--common adjacent to osteosarcomas, osteomyelitis


Why is Ewing's sarcoma commonly found in the diaphysis of long bone?
--it arises from the red bone marrow
--http://imaging.birjournals.org/cgi/content-nw/full/15/4/298/F4




What is geographic appearance?
--geographic lytic: a patch that shows up darker on xray
--confined to a relatively specific area that is more or less easily defined
--likely a benign process


Which condition presents with solitary exostosis that points away from the nearest joint?
--osteochondroma



What is the radiographic difference in appearance between osteochondroma and a benign solitary expansile osteolysis (= ABC)?
--osteochondroma: bony exotosis, cortex continuous with host bone; normal trabeculae, pedunculated or sessile, cartilaginous cap may calcify, projects away from the joint, sessile produces asymmetric widening
--Benign Solitary expansile osteolysis = aneurismal bone cyst: very large, expansile, lytic & separated, markedly thin cortex, only tumor to cross the growth plate (metaphysis to epiphysis)



Compare the incidence of malignant transformation in osteochondroma and hereditary multiple exostosis.
--Osteochondroma: 1% malignant transformation
--HME: 20% malignant transformation

What is a corduroy vertebra?
--a lytic lesion with coarse vertical striations
--usu only at 1-2 vertebral bodies (osteoporosis will be at more levels)
--occurs with hemangiomas (may look like Paget’s disease, osteoporosis)

Is spinal hemangioma commonly solitary or polyostotic?
--Solitary




Which is the most common benign bone tumor of the spine?
--hemangioma (for the entire body it is the osteochondroma)

Is a bone island (endostoma, enostosis) symptomatic?
--No, usu asymptomatic; any bone except skull
--benign, slow growing focus of compact bone
--consists of cartilage cells found where cartilage is not expected


Which condition demonstrates pain worst at night and easily relieved by aspirin?
--osteoid osteoma (benign)
--benign skeletal neoplasm of unknown etiology that is composed of osteoid and woven bone
--nidus of less than 2 cm
--distinct clinical picture of dull pain that is worse at night
--mb jt pain w/ periarticular lesion
--may cause synovitis
--S/Sx: skin temperature increase, sweating, tender
--epiphyseal lesion-->abn growth
--radiolucent nidus surrounded by poss reactive sclerosis in cortex
--center mb partially mineralized or osteolytic or entirely calcified
--Dx: (1) sharp round/oval lesion (2) < 2 cm (3) homogeneous dense center (4) 1-2 mm peripheral radiolucent zone


Which part of the bone is usually involved with osteoid osteoma?
--Can occur in any bone, most common in the cortex but also cancellous, subperiosteal
--50% in femur/tibia, esp prox femur
--20% phalanges
--10% in spine mostly neural arch

What is the appearance of the tumor matrix in enchondroma?
--(mc in phalanges, benign, loc in metaphysis, rare-->malig if solitary)
--stippled matrix calcification and endosteal scalloping
--geographic lytic
--expansile with a thinned cortex, endosteal scalloping
--metaphyseal- diaphyseal, most central
--50% show calcification

--no periosteal rxn, no soft tissue mass


Why is it common to observe a short limb with enchondroma?
--enchondromas are common, usu benign, intra-osseous cartilagious tumors that develop close to growth plate cartilage
--pathological fractures near joint result in limb shortening
--most common tumor of the hands and feet
--achondroplasia is mc skeletal dysplasia characterised by short limb dwarfism
--the mutation that causes achondroplasia affects cartilaginous growth plate in growing skeleton
--enchondromas cause complications includin progressive vertebral fusion even in children, known as Copenhagen syndrome

What is multiple enchondromatosis called?
--Ollier’s Disease (& Maffucci’s syndrome but also has soft tissue hemangiomas/phleboliths)
--multiple enchondromas located in the metaphyseal regions of tubular bones
--usu dxd in childhood
--pts w/ Ollier's dz have increased risk of secondary chondrosarcoma
--risk is about 25% by age 40 yrs;
--mc: bilateral involvement, w/ predominance on one side,frequently involve the short tubular bones of hands and feet as well as long bones of upper and lower extremities
--palpable masses, angular deformity & growth disturbances-->leg length discrepancies
--diaphyseal lesions or metaphyseal lesions which do not cross the growth plate until closure-->severe limb length deformities and angular deformities will develop




What is the most common location of fibrous cortical defect?
--lower extremity (90% in tibia or fibula)
--humerus
--ribs
--ilium
--usu in the cortex (looks soap bubbly to me but not what notes say)



What is a fallen fragment sign?
--bit of cortex drops into simple bone cyst after pathologic fx
--2/3 of simple bone cysts fx
--if it doesn’t fall down, called a trap door sign
--not common but quite characteristic of a simple bone cyst


Which benign bone tumor is named according to its appearance rather than its histological composition?
--ANEURYSMAL BONE CYST
--cystic, blood filled cavity

Describe the radiographic difference between an enchondroma, simple bone cyst, aneurysmal bone cyst and osteochondroma
--Endochondroma – Small round or oval cystic defects in metaphysis, typically with stippled matrix calcification and endosteal scalloping; discrete islands of cartilage surrounded by layers of bone, occur within bone. Long lesions are likely to be painful. Periosteal chondromas occur next cortex under periosteum.
--Simple Bone Cyst – Oblong, central, expansile, radiolucent subepiphyseal osteolytic lesion in metaphysis. At times the partial internal septations may fracture and inferiorly migrate (“fallen fragment” sign); may be fluid filled; clinically silent unless fractured.
--Aneurysmal bone cyst – osteolytic with soap bubble appearance, in metaphysis, can cross growth plate, widely expansile defect of the cortex with cortical buttressing at the region of expansion from the host bone and very thin corticies at the outer edge of the lesion. Cavities are filled with extravasated blood. Pain & swelling. These may be secondary to trauma or concurrent to other tumors. See in clavicle.
--Osteochondroma – Sessile or pedunculated (“coat hanger” exostosis or “cauliflower cap”) cartilage capped bony outgrowth that is continous with underlying bone; abN outgrowth of lateral portion of the growth plate; affects epiphyseal growth.

Is giant cell tumor painful?
--Yes


Is Paget's disease monostotic or polyostotic?
--polyostotic (more than one bone involved)

List the radiographic features of Paget's disease in a long bone
--plain film usu diagnostic; bone scan can identify additional sites
--bone density may increase or decrease
--coarsened (thickened, less distinct) trabeculae

--thickened cortex (less distinct)

--bone expansion
--subarticular extension
--pseudofractures (ie stress fractures through the bone)
--deformities
--skull: osteoporosis cirumscripta; cottonwool appearance

--spine: picture frame vertebra (endplates are thickened/cortex thickened) & ivory vertebra
--pelvis: brim or rim sign (obliteration of Kohler’s teardrop)
--femur and tiba: blade of grass or candle frame appearance; V lesion; saber shin deformity; shepard’s crook (thickened, bowing femur)

--pathologic fracture, most transversely orientated

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