Oncology Flashcards

Question

What nonoperative management can benefit lytic destructive lesion in adult?

Answer 1

Bisphosphonate

Answer 2

1. The goal is to predict impending fractures and prophylactically fix in an elective setting * Avoids urgent hospitalisation and severe pain associated with pathological fractures and allows for medical optimization to minimize the risk of surgery 2. Considers * Site of lesion (UE, LE, trochanteric region) * Nature of lesion (blastic, mixed, lytic) * Size of lesion (\<1/3, 1/3-2/3, \>2/3 of cortex) * Pain (mild, moderate, functional) 3. According to Mirels’ recommendations: * Score \>8 - prophylactic fixation is indicated * Score \<8 - lesion can be managed with radiation or drugs * Score = 8 - clinical dilemma * Probability of fracture is 15% and clinician should use clinical judgement 4. Sensitivity = 91%, specificity = 35% * Specificity of 35% may lead to false positives and unnecessary procedures

Answer 3

1. Avoids urgent hospitalization 2. Decreased perioperative pain 3. Allows for medical optimization 4. Technically easier surgery 5. Shorter OR time 6. Faster recovery/decreased length of stay 7. Allows for coordination with medical oncology

Answer 4

1. Immediate stability, protect the entire bone, reduce pain and increase function 2. Local tumor control * Radiation or local surgical curettage/resection of bone segment 3. Long bones * Closed IM nailing preferred * Without cement if minimal bone destruction * With cement if significant bone destruction * Plates if nonWB bone (eg. humerus) or lesion too proximal or distal for nail * Tumour prosthesis if joint involvement 4. Acetabulum * Harrington technique – threaded pins in ilium as rebar support for cemented acetabular component

Answer 5

1. Remove tumor as fast as possible 2. Be prepared for blood loss – have cement available 3. Notify anaesthesia 4. Call for blood products

Answer 6

1. Known metastatic malignancy 2. Frozen section sent at time of surgery confirming ‘carcinoma’

Answer 7

1. Recognize symptoms * “Stones, bones, abdominal moans, and psychic groans” * Confusion, malaise, fatigue\* * Abdominal pain, nausea\* 2. ECG 3. Hydration * Insert Foley * Bolus IV normal saline 1-2L, then run freely to achieve urine output of 150-200cc/h 4. Loop diuretic (eg. Lasix) * Start once intravascular volume restored 5. Medicine consult * Bisphosphonate * Calcitonin * Dialysis

Answer 8

Extra-articular resection * E.g. knee involvement is performed either by en-block resection or resection with preservation of the extensor mechanism (splitting the patella and detaching suprapatellar pouch from quads tendon and fat pad from patellar tendon)

Answer 9

1. Internal vs External * Internal – limb-sparing surgery * Hemipelvis resected, leg preserved * External – hindquarter amputatio * Hemipelvis and leg amputated 2. Important structures * Sciatic nerve * Femoral neurovascular bundle * Hip joint * \*\*\*General rule = should two of these structures require resection to obtain an adequate margin, then external hemipelvectomy should be performed 3. Flap closure options: * Anterior flap – femoral blood supply * Indicated if tumor involves buttock or internal iliac vessels * Posterior flap (classic) – internal iliac blood supply * Indicated if tumor involves external iliac or femoral vessels * Free flap

Answer 10

1. Classification - Benign active 2. Age = 5-30 3. Presentation: * Classically night pain relieved with ASA or NSAIDs * May cause a painful scoliosis * If so lesion located at the centre of the concavity of the curve 4. Location: * Most common = proximal femur 5. Imaging: * Radiographs = round, well-circumscribed intracortical lesion with radiolucent nidus, surrounding reactive sclerosis, benign periosteal reaction * Nidus is always less than 1.5cm (sclerosis may extend beyond) * CT (thin slice) = identifies radiolucent nidus (often key to diagnosis) * MRI = also can show nidus as well as adjacent edema (not needed routinely) 6. Treatment * Expectant observation and NSAIDs * Pain is self-limiting treated with NSAIDs, burns out on average in 3 years * Radiofrequency ablation (RFA) * Failure of NSAIDs * Contraindicated if adjacent to nerve roots or spinal cord * Recurrence = 10-15% * Surgical resection/currettage * Indicated if close to spinal cord/nerve root/skin, painful scoliosis, digits 7. Differential for cortical osteoid osteoma * Cortical bone abscess * Stress fracture (linear radiolucency) * Intracortical osteosarcoma * Osteoblastoma (\>2cm) 8. Differential for an intramedullary osteoid osteoma * Brodies abscess * Osteoblastoma * Bone island

Answer 11

1. Classification - Benign aggressive 2. Age = 10-30 3. Presentation * Slow, progressive dull, aching pain * Differs from osteoid osteoma in that it is less severe, not night pain, not relieved with ASA 4. Location * Most common = posterior elements of the spine * 2/3 are cortically-based, 1/3 are medullary-based 5. Imaging * Radiographs = radiolucent nidus \>2cm * Surrounding reactive sclerosis * Expansile with neocortex * CT = indicated to evaluate extent of lesion 6. Treatment * Currettage and bone grafting or en bloc resection * Not self limiting so observation not indicated 7. Differential diagnosis * Osteoid osteoma * Brodies abscess * ABC * Osteosarcoma

Answer 12

1. Classification - Benign latent (?) 2. Presentation * Incidental finding 3. Location * Most common = pelvis and proximal femur * Medullary cavity 4. Imaging * Radiographs = round focus of dense bone occasionally with radiating spiculus of bone * MRI = no surrounding edema 5. Treatment * None * Repeat radiographs if diagnosis is in doubt 6. Associated Conditions * Osteopoikilosis = hereditary multiple bone islands

Answer 13

1. Classification - Benign latent (cartilage) 2. Age = 20-50 3. Presentation * Asymptomatic, incidental finding most common * Pain may be associated with: * Lesions in small bones of hands/feet * Pathological fracture * Malignant transformation (\<1% Chondrosarcoma) 4. Location * Most common = hand * Also feet, diaphysis and metaphysis of long bones * Medullary cavity 5. Imaging * Radiographs = rings and stippled calcifications within the medullary cavity * Minimal endosteal erosion (\<50%) * Cortical expansion and thinning may be present in hands and feet (not in long bones) 6. Treatment * Observation * Intralesional currettage and bone grafting * Indications: * Large lesion at risk of recurrent fracture * Radiographs suspicious for low-grade chondrosarcoma * Serial radiographs showing change in lesion 7. Associated Conditions * Ollier disease * Spontaneous mutation * Multiple enchondromas * Associated with shortening and bowing deformities * 25-30% chance of malignant degeneration to low grade chondrosarcoma * Maffucci syndrome * Multiple enchondromas and soft-tissue angiomas * Up to 100% chance of malignant degeneration to low grade chondrosarcoma 8. DDx for solitary enchondroma * Bone infarct * Chondrosarcoma * Chondroblastoma (if affects end of bone) * GCT (if affects end of bone and no calcifications)

Answer 14

1. Classification: Benign active (?) (Cartilage) 2. Age = 10-30 3. Presentation * Pain or incidental finding 4. Location * Surface of long bones and hands 5. Imaging * Radiographs = surface lesion * Saucerization of underlying cortex with rim of sclerosis * Variable calcification 6. Treatment * Observation * Marginal exicision * Symptomatic

Answer 15

1. Classification - Benign (Cartilage) 2. Presentation * Asymptomatic, palpable immobile mass * Pain if inflamed overlying bursa, fracture of stalk, nerve compression, malignant degeneration (higher risk in sessile form) 3. Imaging * Radiographs = Sessile or pedunculated * Cortex of stalk continuous with adjacent bone * Medullary canal continuous with stalk (“corticomedullary continuity”) * Pedunculated grow away from joint 4. Treatment * Observation * Asymptomatic * Marginal resection at base of stalk including cartilage cap (delay until skeletal maturity preferred) * Indications = symptomatic, cosmetic, vascular or nerve compression 5. Associated condition * Multiple Hereditary Exostosis * Autosomal dominant mutation in EXT 1, EXT 2 * EXT-1 has more serious disease manifestations * Associated with: * Short stature * Metaphyseal widening * Primarily sessile lesions * Long bone deformities * Higher risk of malignant transformation (5-10% Chondrosarcoma) * Trevor’s disease * Osteochondroma arising from epiphysis * Most commonly located in tarsals followed by knee

Answer 16

1. Classification - Benign Aggressive (Chondroid) 2. Age = \<25 (80%) 3. Presentation * Progressive pain, limp, decreased ROM, tenderness * Benign pulmonary metastasis (\<1%) 4. Location * Most common = knee (distal femur, proximal tibia) * Also proximal humerus, proximal femur, calcaneus, flat bones * Epiphysis or apophysis, often with extension into the metaphysis 5. Imaging * Radiographs = well circumscribed lytic lesion with sclerotic rim * Stippled calcification (25-40%) * May have cortical expansion 6. Histology * ‘Chicken Wire Calcifications’ surround chondroblasts 7. Treatment * Extended intralesional curretage with bone grafting * Adjuvants include phenol or liquid nitrogen to reduce recurrence * Surgical resection of benign pulmonary metastasis when present 8. Differential diagnosis * Clear cell chondrosarcoma * Bone abscess * Osteonecrosis * Intraosseous ganglion * GCT * Osteoblastoma * Enchondroma

Answer 17

1. Classification - Benign active (chondroid) 2. Age = 10-30 3. Presentation * Pain and mild swelling * May be incidental finding 4. Location * Most common = long bones of lower extremity and pelvis * Also hands and feet * Metaphysis 5. Imaging * Radiographs = lytic, eccentric metaphyseal lesion * Thinning and expansion of adjacent cortical bone * Sharp sclerotic rim 6. Histology * Stellate cells 7. Treatment * Intralesional currettage and bone grafting 8. Differential diagnosis: * NOF * Fibrous dysplasia * ABC * Osteofibrous dysplasia (if in tibia) * GCT (if extends to epiphysis)

Answer 18

1. Classification - Benign latent (fibrous) 2. Age = 5-15 * 30% of children with open physes have NOF 3. Presentation * Asymptomatic, incidental finding * Pathological fracture 4. Location * Most common = long bones of lower extremities * Cortically based, start in metaphysis and migrate to diaphysis 5. Imaging * Radiographs = eccentric, lytic, ‘bubbly’ * Cortically based lesion with sclerotic rim * Cortex may be expanded and thinned * As patient reaches skeletal maturity the lesion ossifies and becomes sclerotic 6. Treatment * Observation * Serial radiographs should be considered for larger lesions * Intralesional currettage and bone grafting * If symptomatic and large lesion * Pathological fractures are treated as per fracture and allowed to heal * Consider intralesional currettage and bone grafting if high risk of recurrence 7. Associated conditions * Familial multifocal * Neurofibromatosis * Jaffe-Campanacci syndrome

Answer 19

1. Classification - Benign active (fibrous) 2. Age = all ages (75% seen in patients younger than 30) 3. Presentation * Asymptomatic, incidental finding * Pathological or fatigue fractures resulting in pain 4. Location * Most common = proximal femur, rib, maxilla, tibia (can affect any bone) * Medullary cavity * Monostotic (single bone) or polyostotic (more than one bone) 5. Imaging * Radiographs = central, lytic lesion * Often ground glass appearing in diaphysis/metaphysis * Surrounding sclerotic rim * May be expansile with cortical thinning * Bowing deformity in proximal femur (Shepherd’s crook) or tibia * Vertebral collapse and kyphoscoliosis 6. Histology * “Chinese letters” or “alphabet soup” appearance * Immature fibrous tissue surrounding islands of woven bone 7. Treatment * Observation * Asymptomatic * Bisphosphonate * Indicated in symptomatic polyostotic fibrous dysplasia * Internal fixation with bone grafting * Indications: * Pain * Impending/actual pathological fracture * Severe deformity * Neurological compromise (spine) * Technique – IM nail preferred over plate * Do not use cancellous autograft as it turns into dysplastic woven bone * Use cortical allograft * Osteotomies * Indication – coxa vara deformity (intertrochanteric osteotomy) 8. Associated conditions * McCune-Albright syndrome * Triad of polyostotic fibrous dysplasia, precocious puberty, café-au-lait spots (coast of Maine) * Mazabraud syndrome * Polyostotic fibrous dysplasia and multiple intramuscular myxomas * Cranial deformities and blindness with craniofacial involvement

Answer 20

1. Classification - Benign active (fibrous) 2. Age = \<10 3. Presentation * Painless swelling over anterior border of tibia * Anterior or anterolateral tibial bowing * Pseudoarthrosis in 10-30% 4. Location * Most common = anterior tibia * Cortically-based, usually diaphyseal 5. Imaging * Radiographs = eccentric, anterior tibia cortical lytic lesion surrounded by sclerosis * No periosteal reaction 6. Treatment * Observation (avoid surgery if possible) * Bracing – if deformity present * Deformity correction * Rarely needed, perform after skeletal maturity if significant deformity present

Answer 21

1. Classification - Benign aggressive (fibrous) * Extremely rare 2. Age = 10-30 3. Presentation * Pain, mass, swelling 4. Location * Any bone * Metaphysis 5. Imaging * Radiographs = lytic lesion central in the metaphysis with soap-bubbly/trabeculated appearance * May appear aggressive 6. Treatment * Wide surgical resection vs. intralesional currettage

Answer 22

1. Classification - 2. Age = \<20 3. Presentation * Solitary disease (EG) * Pain, swelling * Hand-Schuller-Christian disease * Chronic, disseminated form with visceral involvement * Triad = multiple lytic skull lesions, diabetes insipidus, exopthalmus * Letterer-Siwe disease * Infantile, fatal 4. Location * Most common = skull, ribs, clavicle, scapula, vertebrae, long bones, pelvis * Can occur in any bone 5. Imaging * Radiographs = ‘the great mimicker’ * Diaphyseal lesions = classically punched out lytic lesions * Cortex may be thinned or destroyed * May have periosteal reaction (can be geographic or permeative) * Vertebral plana, kyphosis * Cranial lesions = multiple punched out lytic lesions 6. Histology * Mixed inflammatory cell infiltrate * Langerhans cells = indented nuclei (‘coffee bean’) * Stain with CD1a * On electron microscope = Birbeck granules (‘tennis racket’) * Eosinophils = pink cytoplasm * Giant cells are present 7. Treatment * Observation – solitary lesions * Corticosteroid injections (intralesional) – solitary lesions * Low dose irradiation * Reserved for lesions in the spine or lesions not amenable to injection or surgery * Bracing * Prevents kyphosis in vertebra plana (90% effective) * Chemotherapy * Reserved for Hand-Schuller-Christian disease * Intralesional currettage and bone grafting * Risk of impending fracture or articular involvement

Answer 23

1. Classification - Benign active (cystic) 2. Age = \<20 3. Presentation * Most common = pathologic fracture 4, Location * Most common = proximal humerus, proximal femur, ilium, calcaneus * Medullary cavity 5. Imaging * Radiographs = central, lytic, well-demarcated metaphyseal lesion * Expansion and thinning of the cortex * Expansion is no wider than the physis * ‘Fallen Leaf Sign” – pathognomonic * Pathologic fracture where a cortical fragment falls into the base of the lesion * Start adjacent to physis (active) then progress towards diaphysis (latent) * Trabeculated appearance after multiple fractures * MRI = bright on T2, dark on T1 6. Treatment * Observation – asymptomatic lesions * Pathological fracture: * Proximal humerus – nonop * ~15% of lesions fill in with native bone after fracture * Intralesional injection of methylprednisolone * Indicated for active lesions, may require multiple injections * Intralesional currettage, bone grafting and ORIF * Indicated in proximal femur fractures at high risk of pathological fracture or re-fracture * Symptomatic latent cysts that have not responded to injections

Answer 24

1. Classification - Benign aggressive (cystic) 2. Age = \<20 (75%) 3. Presentation * Most common = pain, swelling * Pathological fracture * Neurological symptoms with spine involvement 4. Location * Most common = knee (distal femur, proximal tibia) * Also pelvis, posterior elements of spine * Metaphysis, eccentric 5. Imaging * Radiographs = expansile, eccentric, lytic lesion with soap-bubbly appearance * **Neocortex** * Can expand wider than the width of the physis * MRI = fluid-fluid levels (separation of serum from blood products) 6. Histology * Blood-filled cysts without a true endothelial lining * Lining contains giant cells and spindle cells * “Snakes and blood” 7. Treatment * Extended intralesional currettage and bone grafting * Consider adjuvants phenol and liquid nitrogen * If pathological fracture, treat fracture nonoperative first then currettage (unless spontaneous resolution of ABC) 8. Associated conditions * Arises from other tumours 30% of cases * GCT, chondroblastoma, CMF, NOF, osteoblastoma, FD * Telangiectactic osteosarcoma – radiographic and histological differential 9. Differential diagnosis * UBC * CMF * GCT * Telangiectatic osteosarcoma

Answer 25

1. Classification - Benign aggressive 2. Age = 30-50 3. Presentation * Pain and swelling * Pathological fracture 4. Location * Most common = knee (distal femur, proximal tibia) * Distal radius, proximal humerus, proximal femur, sacral ala, pelvis * Vertebral body when spine involved * Metaphysis, epiphysis, apophysis * Eccentric 5. Imaging * Radiographs = eccentric, lytic lesion located in metaphysis/epiphysis * Often extending to subchondral bone * Expands bone * **Neocortex** ****6. Histology * Scattered giant cells on background of mononuclear stromal cells (neoplastic cells) 7. Treatment * Extensive intralesional currettage and bone grafting or cement * Consider adjuvants phenol or liquid nitrogen * 10-15% recurrence * Adjuvants (PMMA) decrease recurrence compared to bone graft * If cement used WB can be immediate * En bloc resection and reconstruction * Denosumab (controversial) * Assoc complications: * Increased recurrence, arthralgia, headache, nausea, fatigue, pain, anemia, hypercalcemia and osteonecrosis in jaw * Radiation * Lung metastasis (2%) * Thoracotomy, radiation, chemo, or observation * 10-15% die due to mets 8. Associated conditions * Malignant transformation to high grade sarcoma (\<1%) * Secondary ABC

Answer 26

1. Stage IA = low grade, intracompartmental 2. Stage IB = low grade, extracompartmental 3. Stage IIA = high grade, intracompartmental 4. Stage IIB = high grade, extracompartmental 5. Stage III = metastatic disease A = confined to bone, no soft tissue involvement B = penetration of the cortex with a soft tissue mass

Answer 27

1. Classification - Malignant 2. Age = most common 2nd decade (late peak in 6th decade) 3. Presentation * Constant pain (day/night), unrelieved by analgesics * Swelling, decreased ROM, limp, weakness * Pathological fracture (10%) 4. Location * Most common = knee (distal femur, proximal tibia) * Also proximal humerus, pelvis, proximal femur * Typically, medullary cavity 5. Imaging * Radiographs = mixed blastic and lytic non-geographic lesion * Sun-burst periosteal reaction * Codman’s triangle * Soft-tissue mass * MRI full-length bone involved = assess for skip lesions, neurovascular involvement, soft tissue mass * Bone scan = primary lesion very hot * Evaluate for skip lesions * CT chest = order at presentation and assess for lung mets 6. Histology * ‘Lacelike pattern’ of osteoid formed by malignant cells (atypia, abnormal mitotic figures, high nuclear to cytoplasmic ratio) 7. Staging * Enneking * Most common = Stage IIB (high grade, extracompartmental, no metastasis) 8. Treatment * Neoadjuvant chemotherapy * Restage (MRI local, CT chest, bone scan, radiographs) * Surgery * •Limb-sparing surgery with wide-margin resection and reconstruction (preferred) * Reconstructive options include tumour prosthesis, intercalary allograft, APC, rotationplasty * Amputation * Indications: * Pathological fracture * Encasing neurovascular bundle * Poor response to chemotherapy * Adjuvant chemotherapy 9. Prognosis * 70% 5 year survival for localized osteosarcoma in an extremity * 25% 5 year survival for localized pelvic osteosarcoma * Poor prognostic factors * Advanced tumour stage (most important) * Metastatic disease is poor prognostic factor * Most common site = lung (61%), bone (16%) * Response to neoadjuvant chemotherapy * \>90% tumour necrosis associated with increased survival * Skip lesions * Occur in 10%, similar prognosis as lung metastasis * Inadequate surgical margins * Vascular involvement * Elevated LDH, ALP * Expression of VEGF, P-glycoprotein * Expression of multi-drug resistance (MDR) * Axial/pelvic involvement 10. Associated conditions * Retinoblastoma tumour suppressor gene (RB1) carriers * Paget disease * Prior radiation * Rothmund-Thomson syndrome

Answer 28

1. Classification - Malignant 2. Age = 20-45 3. Presentation * Painless mass of long duration * May have limited joint ROM, limp, pain 4. Location * Most common = posterior distal femur (75%) * Also proximal tibia, proximal humerus * Surface of metaphysis 5. Imaging * Radiographs = dense/ossified, lobulated mass arising from the cortex * MRI full length bone = assess for skip lesions, soft tissue involvement, marrow involvement * Bone scan = lesion will be hot * Assess for skip lesions * CT chest = assess for lung mets 6. Treatment * Wide local surgical resection * No chemo or radiation 7. Differential diagnosis * Parosteal osteoma * Melorheostosis * Sessile osteochondroma * Fracture callus * Myositis ossificans

Answer 29

1. Classification - Malignant * Extremely rare 2. Age = 15-25 ' 3. Presentation * Pain 4. Location * Most common = femoral or tibial diaphysis * Cortical/periosteal (no medullary canal involvement) 5. Imaging * Radiographs = sunburst periosteal reaction * Underlying cortex may be saucerized (no medullary involvement) * CT chest = assess for lung mets * Bone scan = hot 6. Treatment * Same as intramedullary osteosarcoma * Neoadjuvant Chemo * Restage * Wide margin resection * Adjuvant Chemo

Answer 30

1. Classification - Malignant * Rare 2. Age, presentation = similar to intramedullary osteosarcoma * Most common 2nd decade (late peak in 6th decade) * Constant pain (day/night), unrelieved by analgesics * Swelling, decreased ROM, limp, weakness * Pathological fracture (10%) 3. Location * Proximal humerus, proximal femur, distal femur, proximal tibia 4. Imaging * Radiographs = purely lytic lesion * Expansile, occasionally obliterates cortex * MRI = fluid-fluid levels, extensive edema 5. Histology * Differentiates from ABC * Gross = “bag of blood” * Atypical mitosis 6. Treatment * Same as intramedullary osteosarcoma * Neoadjuvant Chemo * Restage * Wide margin resection * Adjuvant Chemo

Answer 31

1. Classification - Malignant 2. Arises from: * Pagets * Fibrous dysplasia * Bone infarct * Chronic osteomyelitis * Osteogenesis imperfecta * Irradiation 3. Prognosis * Very poor (as per CORR)

Answer 32

1. Classification - Malignant 2. Age = 20-80 (most common \>40) 3. Presentation * Pain * Swelling, limp, decreased ROM * Pathologic fracture 4. Location * Distal femur, proximal tibia, proximal humerus * Metaphysis 5. Imaging * Radiographs = lytic lesions, often with cortical destruction and soft tissue mass * Variable periosteal reaction * MRI = characterize lesion 6. Histology * Spindle cells arranged in herringbone pattern 7. Treatment * Similar to intramedullary osteosarcoma * Neoadjuvant Chemo * Restage * Wide margin resection * Adjuvant Chemo

Answer 33

1. Classification - Malignant 2. Age = 40-75 3. Presentation * Pain of prolonged duration * Slow growing firm mass * Pathological fractures 4. Location * Most common = pelvis, proximal femur, scapula 5. Imaging * Radiographs * Low grade = similar appearance to enchondroma * High grade = cortical destruction and soft tissue mass * Dedifferentiated = low grade lesion with superimposed high grade destructive area * MRI = assess for cortical destruction, marrow involvement, soft tissue involvement 6. Histology * Low grade = bland appearance, few mitotic figures * High grade = hypercellular cartilaginous lesion with atypical cells that permeate the bone trabeculae 7. Treatment * Intralesional currettage or wide resection = grade I * Wide surgical resection = grade II, III, dedifferentated and pelvic * \*\*\*NOTE – chemotherapy and radiation are generally not effective 8. Associated conditions * Ollier’s * Mutliple hereditary exostosis * Osteochondroma * Enchondroma * Maffucci’s 9. Subtypes * Clear cell chondrosarcoma * Epiphysis * Confused with chondroblastoma * Histology shows extensive clear cytoplasm * Treatment is wide surgical resection * Mesenchymal chondrosarcoma 10. Prognosis * Secondary chondrosarcoma is better than primary * Result is low grade chondrosarcoma * Dedifferentiated chondrosarcoma is the worst

Answer 34

1. Classification - Malignant 2. Age = 5-25 * Median age 15, \>50% adolescents 3. Presentation * Pain * Often fever (20-28% - mistaken for infection) * Swelling, limp, decreased ROM * Palpable mass (34%) * Pathologic fracture (15%) * Delayed presentation/diagnosis common 4. Location * Pelvis, distal femur, proximal tibia, diaphysis of femur, proximal humerus * Presents equally in flat and long bones * Diaphysis 5. Imaging * Radiographs = ill-defined, motheaten, permeative lytic bone destruction * Periosteal reaction (onion skin or sunburst) * MRI = assess for soft tissue and marrow involvement * Soft tissue component in 80% * Bone scan = hot * CT chest = assess for lung mets 6. Histology * Small round blue cells * Immunohistochemical staining positive for CD99 (95%), MIC-2 7. Genetics * t(11:22) [11:22 chromosomal translocation] * Spontaneous translocation * Produces EWS/FLI1 identified by PCR 8. Bone Marrow Biopsy * Done because Ewing’s sarcoma can metastasize via the marrow 9. Treatment * Neoadjuvant chemotherapy (4-8 cycles) * Limb-sparing surgery with wide-margin resection and reconstruction (preferred) * Consider amputation for: * Extremely large tumours involving NV structures * Unmanageable or displaced pathologic fracture * Lesions in the foot or ankle * Adjuvant chemo * Radiation (instead of surgery) for inoperable or metastatic disease * Adjuvant radiation * Reserved for positive margins 10. Prognosis * 80% 5 year survival for localized extremity * 63% 10y survival * 39% 5 year survival for metastasis * 32% 10y survival * Most commonly to lung and bone * Poor prognostic factors * Metastatic disease (most important) * Especially nonpulmonary mets and distant mets * Large tumour (\>8cm, \>100-200mL) * Pelvic tumour * Chemotherapy response (\<90% necrosis) * Older age (\>14) * Male (More common than female 1.5:1) * Elevated LDH (\>200) * Relapse within 2y

Answer 35

1. Classification - Malignant 2. Age = \>40 3. Presentation * Insidious onset of low back or sacral pain * Bowel/bladder symptoms * 50% palpable on rectal exam * Motor/sensory deficits rare (occur below S1) 4. Location * Sacrococcygeal region (50%) * Spheno-occipital region (35%) * Spine (15%) * Central, always has an anterior component * Metastasizes late (lung) 5. Imaging * Radiographs = difficult to assess due to overlying bowel gas * CT = midline bone destruction with soft tissue mass * Calcifications may be present in soft tissue * MRI = lesion bright on T2 6. Histology * Transrectal biopsy contraindicated * Physaliferous cell (signature cell) contains vacuoles and appears bubbly * Keratin positive (differentiated from chondrosarcoma) 7. Treatment * Wide surgical resection * Radiation * Reserved for inoperable tumours, positive margins, local recurrence 8. Differential diagnosis * Chondrosarcoma * Plasmacytoma * Metastasis * Osteomyelitis * Lymphoma

Answer 36

1. Classification - Malignant 2. Age = 20-40 3. Presentation * Pain and tenderness to anterior tibial border * Occasional tibial deformity or mass * History of preceding trauma common 4. Location * Most common = tibial diaphysis (90%) * Intracortical or intramedullary 5. Imaging * Radiographs = multiple well circumscribed lucent defects (soap-bubbly appearance) * No periosteal reaction 6. Histology * Nests of epithelial cells in a benign fibrous stroma 7. Genetics * Controversial whether evolves from osteofibrous dysplasia 8. Treatment * Wide margin surgical resection * Reconstruction often with intercalary allograft * \*\*\*Note – late mets to lung, bones, lymph nodes * Requires long term followup 9. Differential diagnosis * Osteofibrous dysplasia * Fibrous dysplasia * NOF * Osteomyelitis

Answer 37

1. Classification - Systemic (Marrow) 2. Age = \>40 3. Presentation * Bone pain * Pathologic fractures * Cord compression * Recurrent infections 4. Location * Most common = skull, spine, long bones 5. Imaging * Radiographs = multiple, punched out lytic lesions throughout skeleton * No surrounding sclerosis * Skeletal survey to look for additional lesions (bone scan cold) 6. Labs * SPEP, UPEP * Anemia, hypercalcemia, elevated creatinine, elevated ESR * "CRAB" * Calcium high * Renal insufficiency * Anemia * Bone lesions 7. Histology * Plasma cells with eccentric nuclei * Chromatin arranged in ‘clockface’ * Immunohistochemistry = CD38+ 8. Treatment * Chemotherapy (mainstay) * Stem cell transplant - not curative but increases survival * Bisphosphonates – decreases number of bone lesions, bone pain and lowers serum calcium * Surgical stabilization – pathological or impending fractures * Treatment similar to metastatic disease * IM devices preferred * Protect full length of bone

Answer 38

* Plasma cell tumour in a single skeletal location * Progresses to multiple myeloma in 50% of cases * Negative SPEP/UPEP/bone marrow aspirate Treatment * Radiation alone

Answer 39

1. Classification - Systemic (marrow) 2. Age = 35-55 3. Presentation * B symptoms = fever, weightloss, night sweats * Constant pain unrelieved with rest * Large tender, warm soft tissue mass * Pathologic fracture (25%) 4. Location * Most common = femur, spine, pelvis, ribs 5. Imaging * Radiographs = lytic, permeative lesions * Often subtle bone destruction * Soft tissue mass * Multiple sites is common * Ivory vertebrae * CT chest, abdo, pelvis = required for staging * MRI = extensive marrow involvement with soft tissue mass * PET scan = useful for staging and followup 6. Histology * Small round blue cell * Immunohistochemical staining = CD20+, CD45+ 7. Treatment * Chemotherapy * Radiation * Reserved for persistent disease * Surgery * Only for pathological fractures 8. Prognosis * 70% 5 year survival for disseminated disease

Answer 40

1. Classification - Benign (fat) 2. Age = 40-60 3. Presentation * Superficial lipoma – soft, painless, mobile mass * Deep lipoma – usually intramuscular, fixed, painless 4. Location * Superficial * Upper back, shoulders, arms, buttocks, proximal thigh * Deep * Thigh, shoulder, calf 5. Imaging * XR * Radiulucent area within radiodense skeletal muscle * MRI * Isointense with fat on all sequences * T1 = bright * T2 = intermediate * Fat suppressed = suppresses 6. Histology * Mature fat cells 7. Treatment * Observation * Marginal resection * Indicated when symptomatic, growing rapidly

Answer 41

ALT vs WDL * Tumours with identical histology but differ in anatomic location and clinical outcomes * Precancerous * Risk of malignant transformation depends on location and lesional duration ALT * Location * Extremity based or superficial trunk * Most common = thigh * Deep to fascia * ~25% of deep lipomatous masses are ALT * Population * Middle age, peak 50-60s * M=F * Presentation * Deep, large, painless, enlarging mass * Imaging * MRI * Similar to lipomas (isointense to fat) * Differentiated by: * Deep to fascia * Larger (\>10cm) * Thick fibrous septae (\>2cm) * Post-gad enhancement * Histology * In contrast to lipoma: * Pleomorphism * Nuclear atypia * Hyperchromatic stromal cells * Genetics * MDM2 amplification (distinguishes from lipoma) * CDK4 also amplified * Treatment * Marginal excision * Wide excision decreases local recurrence but may be overly morbid for benign tumour * Adjuvant therapies not beneficial * Prognosis * 100% survival * 10% local recurrence (range 8-50%) * Avg 6-8y after surgical excision * 52% re-recurrence * 0-5% risk of malignant dedifferentiation WDL * =ALTs in anatomical locations not amenable to complete surgical resection * Location * Retroperitoneum * 50% of lipomatous masses are WDLs and 45% are dedifferentiated liposarcomas * Mediastinum * Paratesticular * Presentation * Larger than ALTs prior to symptoms/diagnosis * Pain, neuro symptoms, GI bleeding possible * Imaging * CT C/A/P * Required for retroperitoneal masses for planning and staging * Treatment * Wide surgical excision * ~50% of patients require organ removal to achieve en bloc resection * Debulking surgeries for recurrent retroperitoneal tumours have a role in prolonging survival * Prognosis * Mortality rate \>80% * Avg 6-11y to death * Lack metastatic potential but incurable * 10-20% risk of malignant dedifferentiation

Answer 42

1. Classification - Benign (vascular) 2. Age = \<30 * Most common soft tissue mass in kids 3. Presentation * Pain 4. Location * Most common = lower extremities 5. Imaging * Radiographs = phleboliths or calcifications * Adjacent bony erosion may be present * US = helps to differentiate type of lesion * MRI = increased signal intensity on T1 and T2 * “Bag of worms” 6. Treatment * Observation, NSAIDs, compression stockings * Most lesions * IR embolization or sclerotherapy * Reserved for large, painful lesions failing non-op treatment

Answer 43

1. Classification - Benign (nerve) * Benign encapsulated tumor on surface of peripheral nerves composed of Schwann cells 2. Age = 20-50 3. Presentation * Usually asymptomatic * Pain associated with stretch or activity * Positive tinel sign 4. Location * Flexor surfaces of extremities, pelvis 5. Imaging * MRI * T1 = low signal * T2 = high signal * Target sign * Low signal intensity surrounded by high intensity on T2 * Enhances with gadolinium * Nerve may be seen entering and exiting the schwannoma * ‘Split fat sign’ * Fine fat deposition around the lesion and is usually seen as a tapered rim of fat signal adjacent to the proximal and distal ends of the lesion on T1-weighted coronal or axial images * Split fat is produced as a mass grows and normal intermuscular fat is displaced and effaced around the lesion 6. Histology * Verocay body – pathognomonic * Two rows of aligned nuclei in a palisading formation 7. Treatment * Observation – asymptomatic lesions * Marginal excision with nerve fibre preservation – symptomatic

Answer 44

1. Classification - Benign (Reactive/Fibrous) 2. Age = 20-40 3. Presentation * Rapidly enlarging mass over 1-2 weeks (usally 1-2cm in size) * Painful in ~50% 4. Location * Volar forearm, back, chest, head, neck 5. Imaging * MRI = nodularity, usually small * Extension along fascial planes * Enhances with gadolinium 6. Treatment * Marginal resection

Answer 45

1. Classification - Benign (Mesechymal/Mucoid) 2. Age = 40-70 3. Presentation * Painless mass (20% painful) 4. Location * Most common = thigh, buttock, shoulder, upper arm * Often close to neurovascular structures 5. Imaging * MRI = homogenous * T2 = high signal * T1 = low signal * Within muscle groups 6. Histology * Minimal cellularity, no atypia * Cells suspended in abundant mucoid material 7. Treatment * Marginal excision 8. Associated conditions * Mazabraud syndrome * Multiple intramuscular myxomas in same general area as fibrous dysplasia

Answer 46

1. Classification - Benign (Fibrous) * Locally invasive 2. Age = 15-40 3. Presentation * Painless mass * Hard, fixed and deep 4. Location * \>50% are extra-abdominal = shoulder, chest, back, thigh * \<50% are intra-abdominal = pelvis, mesentery 5. Imaging * MRI = T1 - low signal * T2 = low-medium signal * Infiltrative within muscle * Usually 5-10cm in size * Enhances with gadolinium 6. Histology * Bland fibroblasts with abundant collagen * No tumour capsule, often infiltrates into adjacent tissue 7. Treatment * Wide surgical resection * Indicated if resectable * Adjuvant radiation (high risk of recurrence) * Chemotherapy/tamoxifen * Reserved for inoperable lesions 8. Associated conditions * Dupuytrens * Ledderhose disease (plantar fibromatoses) * Gardener syndrome * Familial adenomatous polyposis

Answer 47

1. Classification - Benign (Synovial) 2. Age = 30-50 3. Presentation * Pain, clicking, decreased ROM * Warmth, erythema, tenderness depending on joint * Slow progression of symptoms 4. Location * Most common = hip and knee * Also shoulder and elbow 5. Imaging * Radiographs = variable depending on stage (not visible initially until calcify) * Stippled calcification * MRI = lobular appearance 6. Histology * Gross = hundreds of osteocartilaginous loose bodies * Nodules are hyaline cartilage * Chondrocytes have mild atypia 7. Treatment * Observation = Mild symptoms * Open or arthroscopic synovectomy = symptomatic * May help prevent degenerative changes

Answer 48

1. Classification - Benign (synovial) 2. Age = 30-50 3. Presentation * Recurrent atraumatic hemarthrosis = hallmark * Diffuse form = pain, swelling, effusion, erythema, decreased ROM * Focal form = mechanical symptoms * Extra-articular form * Giant cell tumour of tendon sheath * = small, painless, superficial soft-tissue nodule 4. Location * Most common = knee (80%) * Also hip, shoulder, ankle * Extra-articular form = giant cell tumour of tendon sheath * Most common = hand/wrist 5. Imaging * Radiographs = may show cystic erosions on either side of joint with sclerosis * MRI = T1 and T2 - low signal intensity * “Blooming artifact” * Signal loss on gradient echo sequences * May show extra-articular extension 6. Histology * Gross = frond-like papillary projections * Mononuclear stromal cell infiltrate within the synovium * Hemosiderin-laden macrophages and multinucleated giant cells 7. Treatment * Arthroscopic and open synovectomy * Indicated in symptomatic disease * Marginal excision * Indicated in giant cell tumour of tendon sheath * TKA * Indicated in advanced disease with secondary degeneration * Radiation * Reserved for multiple recurrences

Answer 49

1. Classification - Benign (reactive) 2. Age = 15-35 3. Presentation * Pain, tenderness, swelling, decreased ROM after injury * Followed by mass increasing in size over several months then growth stops and becomes firm 4. Location * Most common = quadriceps, brachialis, gluteal 5. Imaging * Radiographs = initially, irregular, fluffy densities in the soft tissue * Followed by peripheral mineralization and radiolucent centre * MRI = rim enhancement with gadolinium seen within first 3 weeks * CT = defines ossified lesion, looks like an egg-shell 6. Histology * Periphery = mature lamellar bone * Intermediate = poorly defined trabeculae with osteoblasts, fibroblasts and mitoses * Centre = immature, loose, fibrous tissue 7. Treatment * Observation * Self limited process * Size decreases after 1 year * Surgical excision * Indicated only after mature (~6-12 months) and symptomatic

Answer 50

1. Classification - Malignant * Hetergenous group of \>50 types which behave in a similar fashion according to their size, location and grade 2. Age = \>15 (80%) 3. Presentation * Painless enlarging mass * Nontender, firm, well-circumscribed * Constitutional symptoms and lymphadenopathy are uncommon 4. Location * Most common = extremities (60%) * Mets = most commonly lung 5. Imaging * Radiographs = generally nonspecific and nondiagnostic * MRI = enhance with gadolinium, usually respect fascial boundaries * CXR and CT chest = required for staging * CT chest/abdo/pelvis and Bone scan = for myxoid liposarcoma 6. Histology * Core needle biopsy required for indeterminate lesions * Indetermine lesion = MRI cannot diagnose * Determinate lesion = MRI diagnostic * Includes lipomas, hemangiomas, ganglion and synovial cysts, myositis ossificans, and PVNS * Grow in a centripital fashion surrounded by a pseudocapsule * ‘Pushing tumor’ rather than ‘infiltrating tumor’ * Appearance depends on type of sarcoma 7. Staging * AJCC (American Joint Committee on Cancer) * Primary tumour (T) * TX – primary tumour cannot be assessed * T0 – no evidence of primary tumour * T1 - \<5cm * T1a – superficial * T1b – deep * T2 - \>5cm * T2a – superficial * T2b – deep * Regional lymph nodes (N) * NX – cannot be assessed * N0 – no lymph node mets * N1 – lymph node mets * Distant metastasis (M) * M0 – no distant mets * M1 – distant mets * Histological grade (G) * G1 – well differentiated * G2 – moderately well differentiated * G3 – poorly differentiated * G4 – dedifferentiated 8. Treatment * Wide surgical resection with cuff of normal tissue (\>1cm) * Radiation * Pre-operative – lower dose (~50Gy) over ~5 weeks with surgery ~4 weeks after completion * Higher wound complication (35% vs. 17%) * Post-operative – higher dose (~66Gy) * More fibrosis and joint contractures * Chemotherapy * Reserved for high grade, large tumours and mets * 3 soft tissue sarcomas are chemo sensitive: * Embryonal rhabdomyosarcoma * Ewing’s soft tissue sarcoma of bone * (synovial sarcoma) * Surgical resection of lung mets 9. Prognosis * Low grade = 90% 5 year survival * High grade = 50% 5 year survival * Metastasis = 15% 5 year survival * Poor prognostic factors: * Masses \>5cm * Masses deep to fascia * Histologic high-grade * Malignant tumor ulceration * Radiation-induced STS * Bony invasion * Older patient age * Lymph node involvement and mets * Positive margins * Risk factor for local recurrence but not shown to affect survival

Answer 51

SCARE * Synovial sarcoma * Clear cell sarcoma * Angiosarcoma * Rhabdomyosarcoma * Epitheloid sarcoma

Answer 52

1. Classification - Malignant (fibrogenic) * Previously MFH - Malignant Fibrous Histiocytoma 2. Age - 30-80 * Most common soft tissue sarcoma in adults 55-80 3. Presentation * Most common = slow growing, painless mass * May present with fever * May have history of trauma that draws attention to the mass * Painless soft tissue mass may be palpable * Lack of ecchymosis suggests an encapsulated mass * Differentiates from hematoma, which typically presents with ecchymosis after trauma * Neurovascular * Mass effect may cause neurovascular symptoms 4. Location * Lower \> upper extremities \> retroperitoneum 5. Imaging * MRI = T1 - low signal intensity (isointense with muscle) * T2 - high signal intensity 6. Histology * Gross * Nodular, gray-white * 3 subtypes * Pleomorphic (80-85%) * Giant cell (10%) * Inflammatory (\<10%) * Spindled, histiocytic, and multinucleated eosinophilic giant cells * Cells arranged in storiform (cartwheel) pattern arranged around small vessels * Atypia and mitoses present 7. Treatment * Wide surgical resection & radiation therapy * Standard of care in most cases * Radiation is an important adjunct to surgery decreasing local recurrence * 50 Gy pre-op and 66 Gy postop is standard dose for soft-tissue sarcomas * Chemotherapy may be administered in some cases * 50-60% 5-year survival * Amputation * Indication * If unable to resect tumor with negative margins * Resection would result in irreversible damage to major nerves * Patient comorbidities limit potential for recovery after limb-sparing surgery * Good prognosis in absence of metastatic disease

Answer 53

1. Classification - Malignant (fat) * 2nd most common soft tissue tumour (behind UPS) 2. Subtypes * Dedifferentiated liposarcoma * Result of malignant transformation of ALT/WDL * 18% of liposarcomas * Myxoid liposarcoma * Continuum from low-grade well-differentiated myxoid tumours to high grade poorly differentiated round cell tumours * \<20% of liposarcomas * Most common in lower extremity * 2/3 in deep thigh * Can metastasize to sites other than lung including retroperitoneum (mets to fat) * CT chest/abdo/pelvics required for staging * Pleomorphic liposarcoma * 5-15% of liposarcomas * Older patients (\>60) * 2/3 in extremities * Most deep to fascia, 25% subcutaneous 3. Imaging * MRI * Heterogeneous * T1 = hypointense * T2 = hyperintense * Post-gad = heterogeneous enhancement * CT Chest * To assess for lung mets * Myxoid liposarcoma requires CT C/A/P 4. Histology * Dedifferentiated * Discrete areas similar to UPS/fibrosarcoma adjacent to ALT/WDL * Myxoid * Lipoblasts within myxoid stroma * Lipoblast (signet ring-type cell) is a hallmark of liposarcomas * Pleomorphic * Lipoblasts in background of high-grade pleomorphic sarcoma * Lipoblasts differentiate from UPS 5. Genetics * Dedifferentiated = MDM2 and CDK4 amplification * Myxoid = t(12;16) translocation --\> FUS-DDIT3(CHOP) 6. Treatment * Well differentiated = marginal resection * Intermediate and high grade = treat as soft tissue sarcoma * Wide surgical resection with cuff of normal tissue (\>1cm) * Radiation - Pre (~50Gy) or postop (~66Gy) * Chemotherapy for high grade, large tumours and mets * Myxoid * Responsive to chemo and radiation * Especially if high round cell component * Particularly useful in reducing tumour size 7. Prognosis * Dedifferentiated * Local recurrence \>40% * ~100% in retroperitoneum * Distant mets in 15-20% * Most common = lungs, then liver * 5y mortality = 30% * Anatomic location best predictory of outcome * Retroperitoneal is the worst * Myxoid * Depends on % of high grade/round cell component * Low grade has \<10% metastatic risk * High grade has \<35% metastatic risk and mortality rate * Poor prognostic factors * \>10cm * \>25% round cell component * Age\>45 * Spontaneous necrosis * Pleomorphic * Metastatic rate \<50% * 5y survival = 60% * Superficial tumours have better prognosis * Local recurrence \<10% * 0% mets * Poor prognostic factors * Large * Retroperitoneal * Older patient

Answer 54

1. Classification - Malignant (fibrogenic) * Same as MFH - Malignant Fibrous Histiocytoma 2. Age - 30-80 3. Presentation * Most common = slow growing, painless mass * Symptomatic when \>10cm 4. Imaging * MRI = deep seated inhomogeneous mass 5. Histology * Fasiculated growth pattern * Spindle-shaped cells with scant cytoplasm and indistinct borders * Cells separated by interwoven collagen fibers * Tissue may be organized in herringbone fashion 6. Treatment * wide local resection with perioperative radiation indications * Add radiation if tumor is \> 5 cm (5000 cGy before resection and 2000 cGy after resection) * Local adjuvant treatment * Phenol or cryotherapy

Answer 55

1. Classification - Malignant (fibrogenic cutaneous) 2. Age - 20-50 3. Presentation * Most common = slow growing, painless mass * Composed of firm irregular nodules * May have dark red or blue discoloration 4. Location * Trunk \> proximal extremities \> head/neck 5. Imaging * Radiographs * CXR to screen for lung mets in high-risk cases * i.e. recurrence or suspicion for a fibrosarcoma variant of DFSP * MRI * Preop assessment in larger or atypical lesions and recurrent disease * Ultrasound * Monitoring of local DFSP or regional lymph node metastasis * PET * Monitoring of metastatic disease 6. Histology * Biopsy required for diagnosis * Classically = uniform fibroblasts arranged in storiform pattern around an inconspicuous vasculature * Bednar variant has scattered melanin-containing dendritic cells * Fibrosarcomatous variant has a characteristic herringbone pattern 7. Genetics * Mutations associated with t(17;22) * Encodes for PDGF-beta chain (PDGFB)/collagen type I alpha 1 (COL1A1) fusion protein 8. Treatment * Imatinib * 65% response rate * No response in patients who lack the t(17,22) mutation * Indicated in adult patients with unresectable, recurrent, and/or metastatic DFSP * Inhibits PDGF-receptor tyrosine kinase * Wide surgical resection +/- adjuvant radiation therapy * Adjuvant radiation therapy is useful in patients with positive margins or in whom adequate wide excision alone may result in major cosmetic or functional deficits * 15.7% recurrence for lesions on the body * 51.8% recurrence rate for lesions on the head/neck 9. Prognosis * Local recurrence is common * Distant metastasis is rare (\< 5%) * Lung is the most common site * Occurs via hematogenous spread * Usually preceded by multiple local recurrences * Worse prognosis: * Regional lymph node involvement * Fibrosarcomatous progression DFSP variant * Histologic features: high number of mitotic figures, increased cellularity, DNA aneuploidy, TP53 gene overexpression, and the presence of fibrosarcomatous changes * Age \> 50 years old

Answer 56

1. Classification - Malignant * Unknown origin - not synovial 2. Age = 15-40 3. Presentation * Slow growing mass, 50% have pain 4. Location * Arises near joints but rarely involves a joint * Most common = knee, shoulder, arm, elbow, foot * Most common malignant sarcoma of the foot * Can metastasize to regional lymph nodes * Lung mets still more common 5. Imaging * Radiographs = calcification in ~20% * MRI = indeterminate * T1 = low signal * T2 = high signal 6. Histology * Biphasic appearance with two cell types * Spindle cells * Epithelial cells 7. Genetics * t(X;18) chromosomal translocation * SYT-SSX1, 2, or 4 fusion protein 8. Treatment * Same as soft tissue sarcoma * Wide surgical resection with cuff of normal tissue (\>1cm) * Radiation - Pre (~50Gy) or postop (~66Gy) * Chemotherapy for high grade, large tumours and mets

Answer 57

* Most common soft tissue sarcoma of the hand/wrist * CA125 highly expressed in tumour * Firm, painless nodule often confused with RA nodule, granuloma, or skin cancer

Answer 58

Has ability to produce melanin

Answer 59

1. Classification - Malignant (mesenchymal) * Most common soft tissue sarcoma in children 2. 4 subtypes * Embryonal – occurs in infants and young children * Alveolar – occurs in adolescents and young adults * t(2;13) translocation * Botryoid – occurs in infants and young children * Pleomorphic – occurs in adults (40-70) 3. Histology * Immunohistochemistry postive for desmin, myoglobin, MyoD1 4. Treatment * Pleomorphic = as for soft tissue sarcoma * Wide surgical resection with cuff of normal tissue (\>1cm) * Radiation - Pre (~50Gy) or postop (~66Gy) * Chemotherapy for high grade, large tumours and mets * Pediatric rhabdomyosarcoma = chemotherapy and wide surgical excision

Answer 60

• 50% associated with NF-1 * Patients with NF-1 have 5% risk of malignant transformation • Treat as soft tissue sarcoma * Wide surgical resection with cuff of normal tissue (\>1cm) * Radiation - Pre (~50Gy) or postop (~66Gy) * Chemotherapy for high grade, large tumours and mets

Answer 61

1. Classification - Benign (Bone/periosteum) 2. Age = presents before age 40 3. Presentation * Pain, decreased ROM, contractures * Fibrosis of skin common with tense, erythematous, indurated skin 4. Location * Most common = lower extremities 5. Imaging * Radiographs = cortical hyperostosis * ‘Dripping candle wax appearance’ * May flow across joints 6. Treatment * Analgesics * Hyperostotic bone resection with contracture release * Reserved for severe contractures, limited mobility, and pain

Answer 62

1. Classification - Benign peripheral nerve sheath tumour 2. Population - Patients with NF 3. Presentation * May be painful * Firm, possibly tender * + Tinel's sign at mass * Mobile in transverse plane but not longitudinal plane 4. Imaging * MRI * Enhancing heterogeneous lesion * Target sign on T2 * Circumferential high signal (myxoid) around centre of low signal (nerve fibres) * Serial MRI used for monitoring for degeneration to malignancy * To differentiate from Schwannoma: * Schwannoma are eccentric to nerve fibres * Solitary neurofibromas are central to nerve fibres 5. Genetics * Associated with inactivation of NF1 tumor suppressor gene (17q11.2) * Loss of expression of protein neurofibromin * Neurofibromin negatively regulates RAS-mediated pathway * Loss of neurofibromin leads to increased RAS activity * Affects RAS-dependent MAPK activity which is essential for osteoclast function and survival * Rapid hyperplasia of nonmyelinating Schwann cells into neurofibromas after NF1 inactivation * Recruits perineural cells, fibroblasts, mast cells, endothelial cells 6. Treatment * Observe if asymptomatic * Surgical resection if symptomatic * May require nerve grafting 7. DDx * MPNST (malignant peripheral nerve sheath tumor or neurofibrosarcoma) * 5% of patients with NF, 10-25% lifetime risk * Symptoms include painful, enlarging soft tissue mass * Usually from plexiform neurofibroma * 10% of plexiform neurofibromas transform into MPNST * Associated with loss of expression of CDKN2A or TP53 genes in non-myelinating Schwann cells (that also have biallelic inactivation of NF1) * Poor prognosis * Widespread metastasis * High rate of local recurrence