Myoepithelial carcinoma of soft tissue

1What is known

The reference series is 101 myoepithelial tumors of soft tissue, of which 40 were malignant. Patients were 3 to 83 years old, with a mean of 38. Tumors measured 0.7 to 20 cm. Forty-one were in the lower limbs, 35 in the upper limbs, 15 in the head and neck and 10 in the trunk¹.

In soft tissue, a tumor with at least moderate cytologic atypia is classified as malignant. Benign tumors recur in up to 20% and do not metastasize. The carcinoma recurs or metastasizes in up to 40 to 50%².

2Outcomes

Of 31 malignant tumors with follow-up, averaging 50 months, 13 recurred locally, 10 metastasized and four patients died of the disease¹. In 24 adults treated at one sarcoma unit, 13 relapsed (54.2%), 3 locally and 10 with metastases³.

In children, of 23 followed, 52% developed metastases and 43% died, at a median of nine months⁴. See the page on children.

3Genetics

EWSR1 was rearranged in 45% of 66 myoepithelial tumors from outside the salivary glands⁵. Known partners include PBX1, PBX3, POU5F1, ZNF444, ATF1 and KLF15⁵⁶⁷. A subset of malignant tumors lose INI1².

A 2026 study argues that malignant soft-tissue tumors with EWSR1 or FUS fusions are sarcomas, not carcinomas, and found the shortest survival in the SS18::POU5F1, EWSR1::PBX3 and EWSR1::KLF15 groups⁷.

4Treatment reports

Complete surgical resection is the mainstay for localized disease. Of 24 adults, nine received systemic treatment, one had a partial response (to doxorubicin), and median progression-free survival on first-line chemotherapy was 9.3 months. The authors encourage enrollment in trials³.

5The literature

Papers naming the disease that mention this form in title or abstract, by year. Assigned by keyword⁸.

Browse all of them in the directory. See the published cases.

6Most cited papers

7Newest papers

8References