Myoepithelial Carcinoma of Soft Tissue, from the CureRays guide library.

Myoepithelial carcinoma is a rare soft-tissue cancer arising from specialized 'myoepithelial' cells; it is treated mainly with wide surgery and radiation, with the tumor's appearance under the microscope guiding how aggressively it is managed.

What it is.

Myoepithelial carcinoma of soft tissue is a rare cancer that develops from myoepithelial cells — specialized cells that normally sit around glands and help squeeze out their secretions. In soft tissue it usually appears as a deep mass in the limbs, limb girdles, or trunk, and it can occur in both adults and children. It belongs to a family that ranges from benign myoepithelioma to malignant myoepithelial carcinoma, and pathologists tell them apart by how abnormal the cells look. Many of these tumors carry a rearrangement of a gene called EWSR1. Behavior varies: some are relatively indolent while others recur or spread to lymph nodes, lungs, or bone, so treatment is individualized around complete surgical removal, frequently combined with radiation, and long-term follow-up.

How radiation treats it.

Radiation damages the DNA inside cancer cells so they can no longer divide. For myoepithelial carcinoma of soft tissue, radiation works alongside surgery: given before or after the operation, it treats the microscopic cells that extend beyond the visible tumor and lowers the chance of the cancer returning at the original site, especially for higher-grade or larger tumors. For isolated areas of spread in the lung or bone, focused techniques such as SBRT can control disease without another operation. Modern planning concentrates the dose on the target and spares healthy tissue, and proton therapy can further protect sensitive nearby structures. Radiation is painless during delivery, given over a planned course, and external-beam treatment leaves no radioactivity in the body.

The ways we can treat it.

Pre- or post-operative external-beam radiation. Shaped beams treat the tumor bed and a margin to destroy microscopic cells beyond the visible tumor, reducing local recurrence.

Proton therapy (selected sites). When the tumor lies near the spine, pelvis, or other sensitive organs, protons focus the dose on the target while sparing nearby tissue.

Stereotactic body radiation (SBRT). Delivers a few high, focused doses to an isolated spot of lung or bone spread to control it without surgery.

Questions we hear often.

Is every myoepithelial tumor a cancer? No. These tumors range from benign myoepithelioma to malignant myoepithelial carcinoma. Pathologists distinguish them by how abnormal the cells look. The benign forms are cured by removal, while the carcinoma can recur or spread and needs more comprehensive treatment.

How is it treated? The main treatment is wide surgery to remove the tumor with a margin of healthy tissue. Radiation is added before or after surgery for high-grade, large, or close-margin tumors, and chemotherapy is considered for aggressive or widespread disease, especially in children.

Does it behave differently in children? It can. Childhood soft-tissue myoepithelial carcinomas may act more aggressively than in adults, so they are managed at pediatric sarcoma centers where chemotherapy is used more often as part of a coordinated plan.

This guide is informational only. It is not medical advice — please confirm anything here with your care team.