myoepithelial tumors of soft tissue
Like their counterpart in the salivary glands, primary myoepithelial tumors of soft tissue often have a multinodular architecture and are composed of epithelioid, clear, spindle, and/or plasmacytoid cells, frequently arranged in cords or trabeculae in a myxoid or hyalinized stroma.
The cytologic heterogeneity of these tumors is a characteristic feature: the majority of our cases (93%) were composed of more than one myoepithelial cell type, similar to prior studies.
A much higher proportion of myoepithelial tumors in soft tissue could be malignant than those in the salivary gland.
Overall, 46% of the cases in a series were classified as malignant, and interestingly, those arising in children were more likely to be malignant than those in adults (62% vs. 42%, P=0.01).
Although approximately half of salivary gland myoepithelial carcinomas arise in association with a benign mixed tumor or myoepithelioma, this finding is rare in myoepithelial carcinomas of soft tissue: a benign precursor was identified in only 2 of the 40 malignant cases (5%) in Hornick and Fletcher’s series and in 2 of our 29 cases (7%).
Myoepithelial tumors
Myoepithelial tumors have been first described in the salivary glands. Then, they have been recognized in the breast, upper aerodigestive tract and skin, and can arise primarily in soft tissue, albeit infrequently.
See also
myoepithelial carcinoma of the soft tissue
salivary myoepithelial tumors
References
Gleason BC, Fletcher CD. Myoepithelial carcinoma of soft tissue in children: an aggressive neoplasm analyzed in a series of 29 cases. Am J Surg Pathol. 2007 Dec;31(12):1813-24. PMID: #18043035#