malignant ectomesenchymoma

(muh-LIG-nunt EK-toh-meh-ZEN-keh-MOH-muh) A rare, fast-growing tumor of the nervous system or soft tissue that occurs in children and young adults. Malignant ectomesenchymomas may form in the head and neck, abdomen, perineum, scrotum, or limbs. Also called ectomesenchymoma.