myoepithelioma of soft tissue

Definition: Soft tissue myoepithelioma is a rare tumor displaying myoepithelial elements within a hyalinized to chondromyxoid stroma and lacking obvious ductal differentiation. The histogenesis is unclear and most are benign, but some behave in a malignant fashion.

Images

 myoepithelioma of soft tissue

• https://twitter.com/GregHoslerMDPhD/status/737745554961113088
• https://twitter.com/gmayhall/status/762500024341147648

In the recent WHO classification of tumors of soft tissue and bone, myoepithelioma is considered to be part of a spectrum that also embrases mixed tumor and parachordoma.

Myoepithelioma, mixed tumor and parachordoma are uncommon soft tissue tumors thought to represent morphological variants of a single tumor type.

They morphologically resemble mixed tumor of the salivary glands (also known as pleomorphic adenoma), a tumor characterized by deregulated expression of PLAG1 or HMGA2.

Immunochemistry

 IHC positivity for EMA, CK AE1/AE3, S100, calponin and SMA.

See also

 myoepithelioma

References

 Heterogeneous genetic profiles in soft tissue myoepitheliomas. Hallor KH, Teixeira MR, Fletcher CD, Bizarro S, Staaf J, Domanski HA, von Steyern FV, Panagopoulos I, Mandahl N, Mertens F. Mod Pathol. 2008 Nov;21(11):1311-9. PMID: 18604193

 Cytogenetics of a soft tissue malignant myoepithelioma.
van den Berg E, Zorgdrager H, Hoekstra HJ, Suurmeijer AJ
Cancer genetics and cytogenetics. 2004 ; 151 (1) : 87-89.
PMID: 15120917

 Hinze P, Feyler S, Berndt J, Knolle J, Katenkamp D. Malignant myoepithelioma of the vulva resembling a rhabdoid tumour. Histopathology. 1999 Jul;35(1):50-4. PMID: 10383714

 Cytogenetic analysis of a primary salivary gland myoepithelioma.
el-Naggar AK, Lovell M, Callender DL, Ordonez NG, Killary AM
Cancer genetics and cytogenetics. 1999 ; 113 (1) : 49-53.
PMID 10459346