pseudomyogenic hemangioendothelioma

Pseudomyogenic hemangioendothelioma is an extremely rare soft tissue tumor, also named as epithelioid sarcoma-like hemangioendothelioma, which occurs more frequently in young adult males. It was originally recognized as a variant of epitheloid sarcoma, however it is now concluded as a distinctive, rarely metastasizing endothelial neoplasm.

Morphologically, the tumor cells show diversity, composed of large spindle cells and round cells, both with abundant eocinophilic cytoplasm, mimicking rhybdomyoplasts and epitheloid cells respectively.

The tumor cells show diffuse strong expression of Factor VIII, Fli-1, INI-1, vimentin, MDM2, and CDK4, local expression of CD31, AE1/AE3, EMA and P63, and no expression of CD34, S-100, actin-sm, desmin, MyoD1, and HMB45.

Main differential diagnosises:

 epithelioid sarcoma
 malignant peripheral nerve sheath tumor
 rhabdomyosarcoma.

Pseudomyogenic hemangioendothelioma may be confused with a variety of soft tissue neoplasm histologically. A report indicates a relative indolent behavior of this tumor. (26315812)

Open references

 Pseudomyogenic hemangioendothelioma/epithelioid sarcoma-like hemangioendothelioma of the lower limb: report of a rare case. Fan C, Yang L, Lin X, Wang E. Diagn Pathol. 2015 Aug 28;10(1):150. doi : 10.1186/s13000-015-0384-z PMID: 26315812 (Free)