Neoplasms

Question 1

Bone neoplasms

Answer 1

1. Osteosarcoma
2. Chondrosarcoma
3. Ewing Sarcoma

Question 2

Features of osteosarcoma

Answer 2

• malignant, produces osteoid
• 60% male
• bimodal age distribution, 10-25 & 40+, consider Paget’s in older patients

Question 3

Clinical features of osteosarcoma

Answer 3

• XR
• large destructive, lytic or sclerotic mass with permeative margins
• sunburst pattern due to reactive bone formation
• Codman’s triangle (space bw elevated periosteum - due to tumour - & underlying bone becoming filled)
• prognosis - 5y ~70%, mets common

Question 4

Gross morphology of osteosarcoma

Answer 4

• typically in metaphysis of long bones, occasionally in diaphysis
• fleshy, grey-white solid hemorrhage or necrotic tumour
• typically arises within medullary cavity & extends to cortex

Question 5

Microscopy of osteosarcoma

Answer 5

• high grade spindle cell tumour that produces osteoid matrix unconnected by cartilage
• neoplastic osteoid appearance - eosinophilic, homogenous glassy, irregular contours, surrounding atypical tumour cells, lace like pattern of neoplastic bone

Question 6

Variants of osteosarcoma

Answer 6

• osteoblastic osteosarcoma
• fibroblastic osteosarcoma
• chondroblastic osteosarcoma
• low grade osteosarcoma

Question 7

Features of chondrosarcoma

Answer 7

• most common malignant cartilage tumour
• 30-60y, 75% males
• rarely associated with pre-existing chondroma/osteochondroma

Question 8

Clinical features of chondrosarcoma

Answer 8

• XR
• densely calcified mass originating in ileum adjacent to the acetabulum
• ill defined margins
• characteristic dense speckled pattern of calcification highly suggestive of chondroid matrix
• perforation of cortex

Question 9

Treatment of chondrosarcoma

Answer 9

• surgery, mainly
• tumour is radioresistant, little role for chemo
• prognosis - 5y ~80%, recurrence may occur 5-10y after initial excision

Question 10

Gross morphology of chondrosarcoma

Answer 10

• affects long bones, ribs, large lobulated pearly white/light blue tumour
• often with focal calcifaction, myxoid change suggestive of malignancy
• may have areas of hemorrhage & necrosis

Question 11

Microscopy of chondrosarcoma

Answer 11

• tumour cells produce a cartilaginous matrix
• permeative infiltration of trabecular bone & marrow invasion
• no osteoid formation - distinguish from chondroblastic osteosarcoma

Question 12

Features of Ewing sarcoma

Answer 12

• primitive neuroectodermal tumour
• highly malignant
• with small, round rather uniform cells that do not form matrix

Question 13

Pathogenesis of Ewing sarcoma

Answer 13

• unique karyotypic abnormality (90%)

- t(11;22) (q24, q12)

Question 14

Gross morphology of Ewing sarcoma

Answer 14

• affects marrow of femur, tibia, humerus, fibula, pelvis, ribs, vertebra, mandible, clavicle
• may permeate cortex into soft tissue
• soft white (fish flesh) mass of almost liquid consistency

Question 15

Microscopy of Ewing sarcoma

Answer 15

• sheets of small round uniform cells w scant clear cytoplasm & small nucleoli
• may have Homer-Wright rosettes or pseudorosettes

Question 16

Clinical features of Ewing sarcoma

Answer 16

• XR
• destructive lytic tumour, onion skin appearance
• prognosis 5y 75%

Question 17

Treatment of Ewing sarcoma

Answer 17

1. Pre-op chemo
2. Surgery
3. Radiation therapy

Question 18

Differential diagnoses of Ewing sarcoma

Answer 18

• sarcoma
• carcinoma (small cell)
• lymphoma