Soft-tissue tumor with abnormal amianthoid collagen fibers.
 Electron microscopic examination of a solitary soft-tissue tumor from the face demonstrated large areas with abnormal amianthoid collagen fibers in the neoplasm.
 The lesion was classified as a benign neoplasm of myofibroblasts and tentatively named a myofibroblastoma.
 The significance of the amianthoid collagen fibers is unknown.
 Normal native collagen fibers were found in some parts of the neoplasm.
