Summary
Malignant Mixed Tumor - Myoepithelial tumor. These soft tissue tumors are a rare malignant tumor, whose origin is currently considered to be myoepithelial. These tumors have a predilection for the extremities.
Complete Information on this Tumor
Malignant mixed tumor is thought to be the most malignant type of myoepithelial tumors, which range from low-grade or benign, high grade and highly malignant. These soft tissue tumors are a rare malignant tumor, whose origin is currently considered to be myoepithelial. These tumors have a predilection for the extremities. Based on reports, approximately 40% of these tumors occur in the lower limb, around 35% in the upper limb, 15% in the head neck and 10% in the trunk.
Patients present with a soft tissue mass. Approximately two thirds of the masses are cutaneous, and one third are deep. The size of the mass depends on the delay in seeking treatment and location. Reported sizes range from 1 to 20 cm with a mean of approximately 5 cm. Males and females are equally affected. Patients ranged from age 3 to age 83, with a mean of 38.
The tumors ranged from low-grade to high grade, depending on the degree of cytological atypia and abnormal cytomorphology. Low-grade tumors are considered to be myoepithelioma, whereas high-grade tumors are classified as myoepithelial carcinoma (when the epithelioid or spindle cells predominate), or malignant mixed tumor (when cytologically malignant cartilage or bone is present).
Immunohistochemistry shows universal reactivity for epithelial markers such as keratins or epithelial membrane antigen.