Benign bone lesions Flashcards by Seth Wardyn

Small discrete, painful benign bone lesions

osteoid osteoma

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Typical age of osteoid osteoma

5-25

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Most common location for osteoid osteoma

Lower extremity: proximal femur>proximal tibia

Spine: thoracic and lumbar regions, posterior elements, side of concavity in scoliosis (painful in adolescents)

Hand: proximal phalanx

Foot: talar neck

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What is attributed to pain of OO

PGE2 and Cox expression

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Prognosis of OO

pain resolves and lesions spontaneously resolves after 5-7 years

in spine early resection leads to resolutions of scoliosis in <11yos

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Presentation of OO

constant and progressive, worse at night and with ETOH, relieved by NSAIDS

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Appearance on imaging

intensly reactive bone (thickened bone and fibrovascular tissue) around radiolucent nidus (central nodule of woven bone and osteoid with osteoblastic rimming)

<2 cm (if larger think osteoblastoma)

Bone scan: hot area of uptake in nidus, low uptake in reactive zone “double density sign”

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long bone osteomas need to be differentiated from what

stress fracture, osteomyleitis, Ewings sarcoma

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Posterior spinal elements of lesion concerning for OO need to be diff from what

ABC, osteoblastoma

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Treatment of osteoid osteoma

1st line: observation, NSAIDS (also spine w/o scoliosis)

Percutaneous radiofrequency ablation, MR guided high intensity US - failure of medical management

Surgical resection with currettage - not amendable to above (close to skin or nerve), spine lesions with painful scoliosis

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What is most common benign bone tumor in hand

enchondroma

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What is an enchondroma

2nd most common benign cartilage lesion

chondroblasts escape physis

benign hyaline cartilage

asymptomatic (if symptomatic think sarcoma), sometimes pathologic fracture in hand

observation vs curettage and grafting

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What is a periosteal chondroma

painful lesion in cortex of proximal humerus (small lytic area)
10-20yo
Painful due to irritation of tendons
Marginal excision including underlying cortex

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Ollier’s Disease

multiple enchondromatosis, skeletal dysplasia (short, bowing)

10-15% of malignant transformation

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Mafucci’s Disease

Multiple enchondromatosis and soft tissue hemangiomas

highest rate of malignant transformation (50+)

high rate of visceral malignancy

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What is an osteochondroma

most common benign bone tumor

young patients 10-30

arises from cartilage of perichondral ring

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Typical size of cartilage cap of osteochondroma

<1cm, if bigger then suggestive of malignant lesion

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Treatment of osteochondroma

observation, but may remove if issue

Should not grow after skeletal maturity (if does think chondrosarcoma)

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Multiple Hereditary Osteochondral Exostosis

Multiple osteochondroma (sessile or pedunculated)

skeletal abnormalities (coxa valga, tethering of radius with bowing or tethering of fibula)

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Genes for Multiple hereditary exostosis

EXT1,2,3 tumor suppressor genes (affects prehypertrophic chondrocytes causing decreased heparin sulfate production)

Loss of Indian Hedgehog Protein

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What is a chondroblastoma

lytic lesion in epiphyseal or apophyseal area of bone in early teenager

treatment curettage and bone grafting

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What do you see on XR and histo for chondroblastoma

Flecks of calcification on XR, abuts articular surface

chondroblasts with “chicken wire calcification” and cobblestone appears

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What do chondroblastomas stain postive for

S100

What do chondroblastomas and GCT have in common

can present with mets to lung

Also lesion may present with areas of secondary ABC

"Popcorn stippling" bone lesion

enchondroma

Similiar to osteoid osteoma but >2cm and painful, lytic in spine, blastic in extremities

Osteoblastoma lacks peripheral bony reaction (diff. from OO) Curettage and grafting, radiation if unresectable

middle aged, eccentric lytic lesion in metaphysis of in distal femur, distal tibia, distal radius; extends to subchondral surface, metaphyseal side of physis in kids, Cmyc or P53

Giant cell tumor multinucleated giant cells

Treatment of giant cell tumor of bone

curettage and local adjuvent treatment (PMMA/freeze/phenol/argon) could try bisphosphonates (N containing, inhibit farnesyl pyrophospate synthase on osteoclast) Denosumab (prolia) antibody against RANKL, decreases size of lesion

How should teriperatide be given

Forteo, synthetic PTH daily to prevent resorption of bone, receptor on osteoblast if continuous will cause resorption of bone

What must be ordered with Giant Cell Tumor

CT chest: mets to lung

Teenage with expansive, eccentric lytic lesion with bony septae, seen in calcaneous or metatarsals*

ABC, can be in posterior elements of spine Curettage and grafting

What is differntial for ABC lesions

telangiectatic osteosarcoma

Gene translocations of ABC lesion

t(16;17) upregulation of USP6

Young kid with fallen fragment sign in proximal femur or humerus

Unicameral bone cyst observation but may aspirate and inject with steroid if risk of fracture, curettage and bone graft "active if adjacent with physis" latent if not

How to treat UBC with fracture

treat fracture conservatively then deal with UBC

Intrameduallary smoke up chimney sign

Bone infarct same risk factors as osteonecrosis observation

young kid lytic lesion with periosteal reaction, skull, ribs, long bones, spine, kidney bean shape nuclei with eosinophils

Eosinophilic granuloma (langerhand histiocytosis), racquet shaped organelle in EM Treatment curettge and grafting, radiation if very symptomatic

Staining for Eosinophilic granuloma

CD1a

older person, lytic and blastic lesions, usually show skull radiograph, stages, elevated alk phos, hydroxyproline, urinary N telopeptide

Pagets disease lytic lytic and blastic, blastic, burnt out

What else can be associated with Pagets

High output cardiac failure tibia/femur bowing, hip/knee osteoarthritis

Hallmark of pagets disease on histo

mosaic pattern of bone

Genetics of Pagets disease

AD, SQSTM1 - codes for RANK

Treatment of Pagets

Fosamax (bisphosphonates) 2nd line calcitonin (if total joint, cement and pretreat with calcitonin)

infant with unilateral tibial varus, lucency medial cortex of metphysis

focal fibrocartilagenous dysplasia histo: layers of collagenic fibrous tissue resolves on own

Old person with long standing Pagets, no longer responsive to treatment, destruction of bone

high grade osteosarcoma or fibrosarcoma chemo, surgery chemo

Patient with cystic or lytic lesion usually around hip, may be expansile, Ground glass appearance, histo "C and Os

Fibrous dysplasia Tx observation, if symptomatic curettage and internal fixation

Fibrous dysplasia has high expression of what and with what mutation

FGF-23 GS alpha protein (GNAS) on 20q13, affects cAMP pathway, unable to produce normal lamellar bone

Findings of McCune-Albrights syndrome

polystotic fibrous dysplasia, cause of Maine cafe-au-lait spots and endocrinopathy Bisphosphonates can help with pain

kid with lytic lesion of tibia causing anterolateral bowing, histo rimming osteo blasts and fibrous tissue

osteofibrous dysplasia, tx observation *dont confuse with fibrous dysplasia or adamantinoma (nests of epitheliod cells and needs resection)

bubbly eccentric lesion on xray, usually in metaphysis, histo swirling fibrous tissue with giant cells

non-ossifying fibroma tx: observation, may leave Giant Bone Island May be seen with Jaffe-Campancci sydrome (visual problems, MR, cafe-au-lait lesions

lesions with bubbly appearance on xray

NOF, ABC, UBC - NOF may have hemosiderin pigmentation

Osteoid osteoma

Osteoid osteoma distinct demarcation between nidus and reactive bone Nidus: immature osteoid trabeculae (woven bone) with sharp boarder of osteoblastic rimming Reactive zone: surrounding sclerotic border

Pathophysiology of enchondroma

chondroblasts and fragments of epiphyseal cartilage escape from physis, displace into metaphysis and proliferate

Associated conditions with enchondroma

Olliers disease (multiple enchondromatosis), enchondromas throughout long bones Maffucci's syndrome - multiple enchondromas and soft-tissue angiomas, enchondromas markedly expand the bone, angio are round calcified phelboliths, high rate of malignant transformatin

Workup of enchondroma

xray - popcorn stippling, arcs, whorls, rings, minimal erosion, may have cortical expasion in hands and feet or lytic appearance skeletal survay and bone scan in polystotic disease suspected core needle biopsy if bone scalloping or lysis