Localization

 limbs
 orbit
 perineal region
 lungs
 skin (#12131163#)

Variants

 solid alveolar rhabdomyosarcoma (#8172322#, #11280599#)
 * embryonal-like alveolar rhabdomyosarcoma with t(2;20)(q35;p12) (#15120913#)

Cytogenetics

 2q35 rearrangements (PAX3 fusion genes)

• t(2;13)(q35;q14) (2q35 and 13q14)
• t(2;2)(q35;p23) (2q35 and 2p23) creating a PAX3/NCOA1 fusion gene (#15313887#)
• t(2;20)(q35;p12) (2q35 and 20p12) (#15120913#)

 1q36 rearrangements (PAX7 fusion genes)
 t(1;13)(p36;q14) (1p36 and 13q14) creating a PAX7/FOXO1A fusion gene

Molecular biology

 PAX3 fusion genes

• PAX3/FOXO1A by t(2;13)(q35;q14) (55%) (#12039929#, #12550764#)
• PAX3/NCOA1 fusion gene by t(2;2)(q35;p23) (2q35 and 2p23) (#15313887#)

 PAX7 fusion genes

• PAX7/FOXO1A (#12550764#) by t(1;13)(p36;q14) (22%) (#12039929#)

 no fusion transcript detected in 20% of the cases (#12183429#, #12039929#)

 expression of PAX3-FOXO1A and PAX7-FOXO1A identifies a very high-risk subgroup (#12039929#)

Expression profiling: #9823299#

Complications

 disseminated intravascular coagulation
 hyperfibrinolysis

See also

 rhabdomyosarcomas

• embryonal rhabdomyosarcoma
• alveolar rhabdomyosarcoma
• sclerosing rhabdomyosarcoma

References

 Heffner DK. The truth about alveolar rhabdomyosarcoma. Ann Diagn Pathol. 2003 Aug;7(4):259-63. PMID: #12913851#

 Barr FG. Gene fusions involving PAX and FOX family members in alveolar rhabdomyosarcoma. Oncogene. 2001 Sep 10;20(40):5736-46. PMID: #11607823#

 Khan J, Simon R, Bittner M, Chen Y, Leighton SB, Pohida T, Smith PD, Jiang Y, Gooden GC, Trent JM, Meltzer PS. Gene expression profiling of alveolar rhabdomyosarcoma with cDNA microarrays. Cancer Res. 1998 Nov 15;58(22):5009-13. PMID: #9823299#