Malignant Mixed Tumor
Senait W. Dyson, MD
David Cassarino, MD, PhD
Key Facts
Clinical Issues
Slow-growing tumor on extremities and trunk
Local recurrence; regional and distant metastasis
Wide excision with broad margin is primary treatment
Microscopic Pathology
Histologic appearances vary greatly
Composed of an epithelial and chondroid/myxoid stromal component
Epithelial component shows carcinomatous features and benign-appearing islands
Foci of highly atypical cells with hyperchromatic nuclei and numerous mitotic figures
Infiltration of surrounding tissue, vascular invasion and necrosis are helpful diagnostic features
Top Differential Diagnoses
Cutaneous mixed tumor
Biphasic synovial sarcoma
 MMT  arising in a longstanding benign mixed tumor  shows a large, asymmetrical, lobular, and infiltrative tumor invading from the dermis into the subcutaneous tissue. |
 High magnification of an epithelial area shows infiltrative cords of cells, which demonstrate marked cytologic atypia with enlarged, hyperchromatic-staining nuclei surrounding small ductal lumina  . |
TERMINOLOGY
Abbreviations
Malignant mixed tumor (MMT)
Synonyms
Malignant chondroid syringoma
Malignant apocrine mixed tumor
Definitions
Rare variant of a malignant tumor derived from adnexal ductal/gland and myoepithelial cells
CLINICAL ISSUES
