Myoepithelial carcinoma with RB1 mutation: Remarkable chemosensitivity to carcinoma of unknown origin therapy

Myoepithelial carcinoma of soft tissue is a rare, malignant neoplasm that is morphologically and immunophenotypically similar to its counterpart in salivary gland. It demonstrates myoepithelial differentiation, possessing both epithelial and myogenic characteristics.