1. CONTRIBUTION OF CHROMOSOME BANDING AND MOLECULAR CYTOGENETIC ANALYSES FOR THE DIAGNOSIS OF SOFT TISSUE AND BONE TUMORS OVER A 6-YEAR-PERIOD
Manuel Teixeira, MD, PhD
Head of Department of Genetics
Carlos Lopes, MD, PhD
Department of Pathology
Portuguese Oncology Institute, Porto, Portugal

4. Differential diagnosis: Small round cell tumors
Tumor type
Cytogenetics
Genes
Ewing’s sarcoma/PNET
t(11;22)(q24;q12)
t(21;22)(q22;q12)
FLI1/EWS
ERG/EWS
Alveolar rhabdomyosarcoma
t(2;13)(q35;q14)
t(1;13)(p36;q14)
PAX3/FKHR
PAX7/FKHR
Desmopl. small round cell t.
t(11;22)(p13;q12)
WT1/EWS
Neuroblastoma
del(1p), hsr, dmin
MYCN
Non-Hodgkin lymphoma
Typical changes
IG/V, TCR/V

5. Ewing’s sarcoma/PNET
3’EWS
5’EWS

6. Alveolar rhabdomyosarcoma with PAX7-FKHR Bone marow; no primary tumor found

7. Differential diagnosis: Lipomatous tumors
Tumor type
Cytogenetics
Lipoma
12q13~15 changes
6p changes
13q deletions
Atypical lipoma/WD liposarcoma
+r/mar
Lipoblastoma
8q11~13 changes
Fusocellular lipoma
16q13~qter deletions
 Hybernoma
11q13~21 changes
 Liposarcoma
- myxoid/round cell
t(12;16)(q13;p11)
- pleomorphic
Complex changes

8. Atypical lipoma/Well-differentiated liposarcoma
Ampl. MDM2/CDK4
5’CHOP
3’CHOP

9. Myxoid/round cell liposarcoma
5’CHOP
3’CHOP

10. Differential diagnosis: Fusocellular sarcomas
Tumor type
Cytogenetics
Synovial sarcoma
t(X;18)(p11;q11)
Fibrosarcoma
Complex karyotype
Malign. perypheral nerve sheath t.

11. Synovial sarcoma
5’SYT
3’SYT

12. Types of genetic findings and their relevance for differential diagnosis
Apr Mar. 2007
N=163/614

13. Patients with a pathognomonic genetic finding

14. Desagreement rate in patients with a pathognomonic genetic finding
2 ERMS
Extraskel. myxoid chondrosarcoma
2 lipomas, 2 myxoid
lipos; 1 MSFT
Small cell osteos.
1 myxoid lipos;
1 sarcoma NOS

15. Patients with informative but not pathognomonic genetic findings

16. Patients with informative genetic findings decisive for differential diagnosis

17. Patients with informative genetic findings compatible with morphologic diagnosis

18. Patients with informative genetic findings not compatible with morphologic diagnosis

19. Conclusions
42% of the tumors with genetic changes presented a pathognomonic chromosome alteration
Additional 25% of the tumors with genetic changes had an informative result for differential diagnosis
In 16% of the tumors presenting a pathognomonic chromosome change, the initial morphologic diagnosis was changed as a result of the cytogenetic finding
The tumor types that benefited most from the cytogenetic data for their correct diagnosis were alveolar rhabdomyosarcoma, well differentiated liposarcoma, synovial sarcoma, Ewing’s sarcoma, and myxoid liposarcoma

20. Thanks!