bone neoplasms

Question 1

common presentation of bone neoplasms

Answer 1

• pain
• mass
• swelling of affected area
• fracture
• loss of function
• metastasis to lungs, bone or bone marrow

Question 2

investigations for bone neoplasms (+ rationale)

Answer 2

x-ray: mineralization and spread pattern
MRI/CT: outline tumour mass effect
bone radionuclide scan: detect spread
PET scan: check body for metastasis
biopsy: for diagnosis

Question 3

prognostic factors for bone neoplasms

Answer 3

• size of tumours (T1<8cm, T2>8cm)
• histopatho grading
• location and margin clearance
• staging
• response to chemotherapy

Question 4

types of osteogenic tumour

Answer 4

1. osteoid osteoma (benign)
2. osteoblastoma (benign)
3. osteosarcoma (malignant)

Question 5

osteosarcoma risk factors

Answer 5

male, 10-25yo, precursor lesions in older patients

Question 6

osteosarcoma x-ray presentation

Answer 6

large, destructive, lytic/blastic mass, permeative margins, breaking thru cortex to elevate periosteum, sunburst pattern due to new bone formation

Question 7

location of osteosarcoma

Answer 7

• metaphysis (growth plate) of long bones
• starts in medullary cavity and extends to cortex
• fleshy appearance (necrosis and haemorrhage)

Question 8

histological appearance of osteosarcoma

Answer 8

cytological atypia, lace-like osteoid pattern produced by eosinophilic matrix entrapping anaplastic tumour cells

Question 9

types of cartilage tumour

Answer 9

1. chondroblastoma (benign)
2. chondromyxoid fibroma / CMF (benign)
3. osteochondroma (benign)
4. chondroma (benign)
5. chondrosarcoma (malignant)

Question 10

osteochondroma presentation

Answer 10

benign cartilage-capped tumour (bone extension containing cortex and periosteum covered by a thin cartilagenous cap)

Question 11

chondroma types

Answer 11

• endochondroma (inside bone)
• subperiosteal chondroma (bone surface)
• soft tissue chondroma (inside soft tissue)

Question 12

risk factors for chondrosarcoma

Answer 12

30-60yo, male, preexisting bone tumour

Question 13

presentation of chondrosarcoma

Answer 13

malignant bone tumour that produces cartilage

large (≥8cm) and painful tumour of long bones, grows rapidly during adolescence, not chemo sensitive

Question 14

macroscopic presentation of chondrosarcoma

Answer 14

• large lobulated tumour with pearly white/light blue focal calcification
• commonly, myxoid change
• haemorrhagic necrosis
• cartilagenous matrix
• permeation of bone trabeculae
• soft tissue and marrow invasion

Question 15

histologic grading of chondrosarcoma

Answer 15

based off cellularity, nuclear changes of chondrocytes (well differentiated is grade 1, poorly differentiated is grade 3), and aggression aka metastasis

Question 16

types of giant cell rich tumours

Answer 16

giant cell tumour, giant cell reparative granuloma, pigmental villonodular synovitis, brown tumour: all usually benign

Question 17

most common presentation for giant cell rich tumours

Answer 17

30-50yo F px from oriental country, solitary tumour in long tubular bone epiphyseal/metaphyseal region

Question 18

histological presentation of giant cell tumour

Answer 18

• abundant giant cells with 50-100 nuclei per cell
• stromal cells similar to giant cells
• no osteoid formation

Question 19

pathology of fibrous dysplasia

Answer 19

gain in function mutation of GNAS1 gene causing growth of undifferentiated bone tumour (usually during skeletal development)

Question 20

types of fibrous dysplasia

Answer 20

monostotic: single bone
polyostotic: multiple bones, might be a syndrome (Mazabraud syndrome, McCune-Albright syndrome)

Question 21

histological presentation of fibrous dysplasia

Answer 21

• tan-white, gritty tissue
• curvilinear trabeculae of woven bone (looks like Chinese characters to racists) surrounded by moderately cellular fibroblastic proliferation
• bone lacks prominent osteoblastic rimming