Bone and Soft Tissue Flashcards
Giant Cell Rich Lesions of Bone
GCT of Bone (G34W mutation)
Primary ABC (USP rearranged)
Non-Ossifying Fibroma
Central and peripheral giant cell granuloma of jaw
Brown tumour of hyperparathyroidism
Chondroblastoma (K36M mutation)
Giant cell rich osteosarcoma
Risk Stratification in Solitary Fibrous Tumour
Age of patient (< or > 55 yo)
Tumour size (5, 10, 15cm cut offs)
Mitotic count (per 10 HPF)
Presence of necrosis (< or >10%)
Score for each parameter which are then added to give a total score (low, intermediate or high risk of metastasis)
Staging and Grading of Soft Tissue Sarcomas
Unlike other organ systems staging of soft tissue sarcomas is largely determined by grade.
No agree upon grading system but AJCC 8th ed uses FNCLCC system (other main system is NCI).
Not all soft tissue sarcomas are staged or graded:
e. g. DFSP and WDLPS are of intermediate malignancy and low grade by definition.
e. g. Ewing sarcoma, Angiosarcoma, Malignant rhabdoid tumour, DSRCT are all high grade by definition
e. g. ESMC, ASPS, ES, LGFMS and clear cell sarcoma not graded as grade does not predict outcome
FNCLCC system is based on:
Tumour differentiation score (depends on how closesly rumour resembles normal tissue of origin, table in CAP)
Mitotic activity (10 HPF or per 1 mm2)
Necrosis (< or > 50% tumour cell necrosis)
Each parameter is assigned a score then the scores are summed to give an overall grade (Grade 1 = low grade, Grade 2 & 3 = high grade)
AJCC Staging System is based on:
Site (H&N, trunk, extremites, retroperitoneum)
Size of tumour
Extent of involvement
Synoptic Reporting of Soft Tissue Sarcomas
Clinical:
Pre resection therapy and what type
Specimen:
Procedure, tumour focality, tumour site, tumour size
Histologic type (WHO)
Histologic Grade (FNCLCC)
Mitotic Rate
Necrosis
Treatment Effect
Lymphovascular Invasion
Margins
Regional lymph nodes (if included)
Distant Metastases (if applicable)
EWSR1 Rearranged Tumours
Ewing Sarcoma (FLI1, ERG)
Extraskeletal myxoid chondrosarcoma (NR4A3)
Clear cell sarcoma (ATF1, CREB1)
Clear cell carcinoma of salivary gland (ATF1)
Angiomatoid fibrous histiocytoma (ATF1, CREB1)
Desmoplastic small round cell tumour (WT1)
Soft tissue myoepithelial tumour (POU5F1, PBX1)
FUS Rearranged Tumours
Angiomatoid fibrous histiocytoma (ATF1)
LGFMS (CREBL2/3)
Sclerosing epithelioid fibrosarcoma (CREB3L2)
Myxoid liposarcoma (DDIT3)
Gene Rearrangements in Fatty Tumours
ALT / WDLPS / DDLPS (MDM2 amplification)
Myxoid liposarcoma (DDIT3 - EWSR1 or FUS)
Spindle cell lipoma (RB deletion)
Lipoblastoma (PLAG1)
Sarcomas that Metastasis to Lymph Nodes
SCARE
Synovial sarcoma
Clear cell sarcoma
Angiosarcoma
Rhabdomyosarcoma
Epithelioid sarcoma
MDM2 Amplified Tumours
ALT / WDLPS / DDLPS
Low grade central osteosarcoma
Parosteal osteosarcoma
Intimal sarcoma
USP6 Rearranged Tumours
Primary ABC
Giant cell lesion of the small bones
Nodular fasciitis
Myositis ossificans
Fibroosseous pseudotumour of digits
Cellular fibroma of tendon sheath
Molecular Changes in Bone Tumour
Osteochondroma: EXT1, EXT2 loss of function mutations
Enchondroma: IDH1, IDH2 mutations
Osteoid osteoma & OB: FOS, FOSB rearrangements
NOF: KRAS, FGFR1, NF1 alterations
Desmoplastic fibroma: CTNNB1, APC mutations
GCT of bone: H3 G34M mutation, RANKL overexp.
Chondroblastoma: H3 K36M mutation
ABC: USP6 rearrangement
LCH: BRAF V600E
Fibrous dysplasia: GNAS activating mutations
LG central & Parosteal OS: MDM2 amp, CDK4 (chr 12)
LG central CS: IDH1 / 2
LG peripheral CS: EXT1 / EXT2
Ewing Sarcoma: EWSR1 rearrangements
PMT: FGF gene rearrangements
Mesenchymal CS: HEY1-NCOA2 fusion
Syndromes Associated with Chondroid Tumours
Olliers (multiple enchondromas)
Mafucci (enchondromas & haemangiomas)
Multiple hereditary exostoses
Risk Factors for Osteosarcoma in Adults
Paget disease of the bones
Radiotherapy to the bones
Herediatry conditions: Hereditary retinoblastoma, Li-Fraumeni syndrome
Epiphyseal Bone Tumours
Chondroblastoma
Giant cell tumour of bone
Clear cell chondrosarcoma
Can also consider: ABC, UBC, osteomyelitis
Osteolytic Lesions in <30 y/o
Infection / osteomyelitis
Chondroblastoma
Chondromyxoid fibroma
Enchondroma
ABC
Fibrous dysplasia
Non-ossifying fibroma