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'''Rhabdomyosarcoma''', often abbreviated ''RMS'', is a malignant tumour of skeletal muscle. | {{ Infobox diagnosis | ||
| Name = {{PAGENAME}} | |||
| Image = Alveolar_rhabdomyosarcoma_-_very_high_mag.jpg | |||
| Width = | |||
| Caption = Alveolar rhabdomyosarcoma. [[H&E stain]]. | |||
| Synonyms = | |||
| Micro = +/-rhabdomyoblasts (eccentric nucleus, moderate amount of intensly eosinophilic cytoplasm, striations - not common); alveolar RMS: alveolus-like pattern (classic); embryonal RMS: [[small round cell tumour]] | |||
| Subtypes = embryonal (spindle cell subtype, botryoid), alveolar (translocation-positive, translocation-negative), undifferentiated | |||
| LMDDx = [[small round cell tumours]] - esp. [[small cell carcinoma]] and (large cell) [[lymphoma]]s | |||
| Stains = | |||
| IHC = desmin (best marker) +ve, actin +ve, myogenin +ve, CD56 +ve (common), synaptophysin -ve/+ve, chromogranin -ve/+ve, cytokeratins -ve/+ve | |||
| EM = sarcomeric like structures - typically in U-shaped cells | |||
| Molecular = alveolar RMS (~85% of cases): t(2,13) PAX3/FKHR fusion gene ''or'' t(1,13) PAX7/FKHR fusion gene | |||
| IF = | |||
| Gross = | |||
| Grossing = | |||
| Site = [[soft tissue]] - skeletal muscle site (alveolar RMS), non-skeletal muscle site (embryonal RMS) | |||
| Assdx = | |||
| Syndromes = [[DICER1 syndrome]] for ''embryonal rhabdomyosarcoma'' | |||
| Clinicalhx = alveolar RMS: young adult or adolescent; embryonal RMS: typically <10 years old | |||
| Signs = | |||
| Symptoms = | |||
| Prevalence = not common | |||
| Bloodwork = | |||
| Rads = | |||
| Endoscopy = | |||
| Prognosis = | |||
| Other = | |||
| ClinDDx = other soft tissue tumours | |||
| Tx = | |||
}} | |||
'''Rhabdomyosarcoma''', often abbreviated '''RMS''', is a [[malignant]] tumour of skeletal muscle. | |||
==General== | ==General== | ||
*Most common paediatric sarcoma. | *Most common paediatric [[sarcoma]]. | ||
**Classically in the head and neck region.<ref name=pmid10465231>{{Cite journal | last1 = Rosenthal | first1 = TC. | last2 = Kraybill | first2 = W. | title = Soft tissue sarcomas: integrating primary care recognition with tertiary care center treatment. | journal = Am Fam Physician | volume = 60 | issue = 2 | pages = 567-72 | month = Aug | year = 1999 | doi = | PMID = 10465231 | URL = http://www.aafp.org/afp/1999/0801/p567.html }}</ref> | **Classically in the head and neck region.<ref name=pmid10465231>{{Cite journal | last1 = Rosenthal | first1 = TC. | last2 = Kraybill | first2 = W. | title = Soft tissue sarcomas: integrating primary care recognition with tertiary care center treatment. | journal = Am Fam Physician | volume = 60 | issue = 2 | pages = 567-72 | month = Aug | year = 1999 | doi = | PMID = 10465231 | URL = http://www.aafp.org/afp/1999/0801/p567.html }}</ref> | ||
*Most common sarcoma in [[Li-Fraumeni syndrome]].<ref name=PST14feb11> | *Most common sarcoma in [[Li-Fraumeni syndrome]].<ref name=PST14feb11>Thorner, Paul S. 14 February 2011.</ref> | ||
*~6% of all childhood cancer. | *~6% of all childhood cancer. | ||
| Line 12: | Line 43: | ||
#*Usually young adults/adolescents. | #*Usually young adults/adolescents. | ||
#*Early mets common. | #*Early mets common. | ||
#* | #*Usually arises in regions with skeletal muscle. | ||
#Embryonal rhabdomyosarcoma. | #Embryonal rhabdomyosarcoma. | ||
#*Usual <10 years old. | #*Usual <10 years old. | ||
#*Typically locally invasive. | #*Typically locally invasive. | ||
#* | #*Usually arises in regions '''without''' skeletal muscle. | ||
Less common types:<ref name=pmid12110339>{{Cite journal | last1 = Hicks | first1 = J. | last2 = Flaitz | first2 = C. | title = Rhabdomyosarcoma of the head and neck in children. | journal = Oral Oncol | volume = 38 | issue = 5 | pages = 450-9 | month = Jul | year = 2002 | doi = | PMID = 12110339 }}</ref> | Less common types:<ref name=pmid12110339>{{Cite journal | last1 = Hicks | first1 = J. | last2 = Flaitz | first2 = C. | title = Rhabdomyosarcoma of the head and neck in children. | journal = Oral Oncol | volume = 38 | issue = 5 | pages = 450-9 | month = Jul | year = 2002 | doi = | PMID = 12110339 }}</ref> | ||
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==Microscopic== | ==Microscopic== | ||
===Alveolar rhabdomyosarcoma=== | ===Alveolar rhabdomyosarcoma=== | ||
Features:<ref name=PST14feb11 | Features:<ref name=PST14feb11/> | ||
*Alveolus-like pattern -- '''key low-power feature'''. | *Alveolus-like pattern -- '''key low-power feature'''. | ||
**Fibrous septae lined by tumour cells. | **Fibrous septae lined by tumour cells. | ||
| Line 57: | Line 88: | ||
Other features: | Other features: | ||
*Nuclear pleomorphism - common. | *[[Nuclear pleomorphism]] - common. | ||
*Mitoses - common. | *Mitoses - common. | ||
| Line 65: | Line 96: | ||
DDx: | DDx: | ||
*[[Alveolar soft part sarcoma]]. | *[[Alveolar soft part sarcoma]]. | ||
*Skeletal muscle regeneration.<ref name=pmid9762546>{{Cite journal | last1 = Guillou | first1 = L. | last2 = Coquet | first2 = M. | last3 = Chaubert | first3 = P. | last4 = Coindre | first4 = JM. | title = Skeletal muscle regeneration mimicking rhabdomyosarcoma: a potential diagnostic pitfall. | journal = Histopathology | volume = 33 | issue = 2 | pages = 136-44 | month = Aug | year = 1998 | doi = | PMID = 9762546 }}</ref> | |||
Images | ====Images==== | ||
<gallery> | |||
Image:Alveolar_rhabdomyosarcoma_-_intermed_mag.jpg | Alveolar RMS - intermed. mag. (WC) | |||
Image:Alveolar_rhabdomyosarcoma_-_very_high_mag.jpg | Alveolar RMS - very high mag. (WC) | |||
</gallery> | |||
www: | |||
*[http://path.upmc.edu/cases/case489.html Alveolar RMS - several images (upmc.edu)]. | |||
===Embryonal rhabdomyosarcoma=== | ===Embryonal rhabdomyosarcoma=== | ||
Features:<ref name=PST14feb11 | Features:<ref name=PST14feb11/> | ||
*Randomly arranged small cells. | *Randomly arranged small cells. | ||
*[[Myxoid]] matrix. | *[[Myxoid]] matrix. | ||
| Line 127: | Line 160: | ||
*Actin. | *Actin. | ||
*Myogenin. | *Myogenin. | ||
For [[head and neck pathology|head and neck]] RMS:<ref name=pmid18487991>{{Cite journal | last1 = Bahrami | first1 = A. | last2 = Gown | first2 = AM. | last3 = Baird | first3 = GS. | last4 = Hicks | first4 = MJ. | last5 = Folpe | first5 = AL. | title = Aberrant expression of epithelial and neuroendocrine markers in alveolar rhabdomyosarcoma: a potentially serious diagnostic pitfall. | journal = Mod Pathol | volume = 21 | issue = 7 | pages = 795-806 | month = Jul | year = 2008 | doi = 10.1038/modpathol.2008.86 | PMID = 18487991 }}</ref> | |||
*CD56 +ve. | |||
*Synaptophysin -ve/+ve (seen in 12 of 37 cases<ref name=pmid18487991/>). | |||
*Chromogranin A -ve/+ve (seen in 8 of 36 cases<ref name=pmid18487991/>). | |||
*Wide-spectrum cytokeratin -ve/+ve. | |||
*CAM5.2 -ve/+ve. | |||
For [[urinary bladder]] RMS in adults: | |||
*Myogenin +ve. | |||
*Desmin +ve. | |||
*Keratins -ve.<ref name=pmid21762516>{{Cite journal | last1 = Bing | first1 = Z. | last2 = Zhang | first2 = PJ. | title = Adult urinary bladder tumors with rhabdomyosarcomatous differentiation: clinical, pathological and immunohistochemical studies. | journal = Diagn Pathol | volume = 6 | issue = | pages = 66 | month = | year = 2011 | doi = 10.1186/1746-1596-6-66 | PMID = 21762516 }}</ref> | |||
**Keratin positive tumours are considered ''rhabdomyosarcomatous sarcomatoid carcinoma'' or ''sarcomatoid carcinoma with rhabdomyosarcomatous differentiation''. | |||
===Subtyping via IHC=== | ===Subtyping via IHC=== | ||
PST proposes<ref name=PST14feb11 | PST proposes<ref name=PST14feb11/> the following (presumably based on Makawitz et al.<ref name=pmid18788888>{{cite journal |author=Makawita S, Ho M, Durbin AD, Thorner PS, Malkin D, Somers GR |title=Expression of insulin-like growth factor pathway proteins in rhabdomyosarcoma: IGF-2 expression is associated with translocation-negative tumors |journal=Pediatr. Dev. Pathol. |volume=12 |issue=2 |pages=127–35 |year=2009 |pmid=18788888 |doi=10.2350/08-05-0477.1 |url=}}</ref>): | ||
{| class="wikitable sortable" style="margin-left:auto;margin-right:auto" | {| class="wikitable sortable" style="margin-left:auto;margin-right:auto" | ||
| '''IHC''' | | '''IHC''' | ||
| Line 163: | Line 209: | ||
==[[Electron microscopy]]== | ==[[Electron microscopy]]== | ||
Features: | Features: | ||
*Sarcomeric like structures - | *Sarcomeric like structures - usually in "bent" cells; cells that are U-shaped. | ||
==Molecular diagnostics== | ==Molecular diagnostics== | ||
| Line 178: | Line 224: | ||
*t(1,13) vs. t(2,13) -- t(1,13) usually: younger age, extremity lesion, localized disease, better survival. | *t(1,13) vs. t(2,13) -- t(1,13) usually: younger age, extremity lesion, localized disease, better survival. | ||
*Several uncommon [[translocations]] exist. | *Several uncommon [[translocations]] exist. | ||
*'''Important''' for [[urinary bladder]] lesions in adults: the presence of a translocation is more-or-less required for the diagnosis of RMS.<ref name=pmid21762516>{{Cite journal | last1 = Bing | first1 = Z. | last2 = Zhang | first2 = PJ. | title = Adult urinary bladder tumors with rhabdomyosarcomatous differentiation: clinical, pathological and immunohistochemical studies. | journal = Diagn Pathol | volume = 6 | issue = | pages = 66 | month = | year = 2011 | doi = 10.1186/1746-1596-6-66 | PMID = 21762516 }}</ref> | |||
**It is suggested that keratin negative tumours without molecular testing to corroborate the impression of RMS be referred to as ''rhabdomyomatous tumours''.<ref name=pmid21762516/> | |||
===Embryonal rhabdomyosarcoma=== | |||
*Chromosome 11p loss of heterozygosity.<ref name=pmid17652054>{{Cite journal | last1 = Gallego Melcón | first1 = S. | last2 = Sánchez de Toledo Codina | first2 = J. | title = Molecular biology of rhabdomyosarcoma. | journal = Clin Transl Oncol | volume = 9 | issue = 7 | pages = 415-9 | month = Jul | year = 2007 | doi = | PMID = 17652054 }}</ref> | |||
Note: | |||
*Not used for diagnosis. | |||
==See also== | ==See also== | ||