Difference between revisions of "Soft tissue lesions"

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Soft tissue lesions (view source)

Revision as of 20:03, 7 March 2011

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→‎Skeletal muscle tumours: split-out RMS
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=Skeletal muscle tumours=
=Skeletal muscle tumours=
==Rhabdomyoma==
{{Main|Rhabdomyoma}}
==Rhabdomyosarcoma==
==Rhabdomyosarcoma==
*Often abbreviated ''RMS''.
*Abbreviated ''RMS''.
===General===
*Most common paediatric sarcoma.
*~6% of all childhood cancer.
 
Histological subdivision:
#Alveolar rhabdomyosarcoma.
#*Usually young adults/adolescents.
#*Early mets common.
#Embryonal rhabdomyosarcoma.
#*Usual <10 years old.
#*Typically locally invasive.
 
Molecular and histologic subdivision:
#Translocation-positive alveolar RMS.
#Translocation-negative alveolar RMS.
#Embryonal RMS.
 
Notes:
*Translocation-negative alveolar RMS shares characteristics with ''embryonal RMS''.
 
===Microscopy===
Alveolar rhabdomyosarcoma:
*Alveolus-like pattern:
**Fibrous septae lined by tumour cells.
***Space between fibrous sepate may be filled with tumour: ''solid variant of alveolar rhabdomyosarcoma''.
*Eccentric nucleus (???).
*Cytoplasm - dense pink staining on H&E (if well differentiated).
*Usu. nuclear pleomorphism +++.
*Mitoses common.
 
===Molecular diagnostics===
====Alveolar rhabdomyosarcoma====
Common translocations (~80%):
*t(1,13).
**PAX7/FKHR fusion gene.
*t(2,13).<ref>URL: [http://www.ncbi.nlm.nih.gov/omim/606597 http://www.ncbi.nlm.nih.gov/omim/606597]. Accessed on: 18 August 2010.</ref>
**PAX3/FKHR fusion gene.


Several uncommon translocations exist.
{{Main|Rhabdomyosarcoma}}
Comes it two main flavours:
*Alveolar rhabdomyosarcoma.
*Embryonal rhabdomyosarcoma.


===IHC===
The histology may be that of a [[small round cell tumour]].
*Desmin (best marker).
*Actin.


=Chondro-osseous tumours=
=Chondro-osseous tumours=
Michael
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