| Interlacing bundles of smooth muscle fibres, which may be interspersed by varying amounts of fibrous connective tissue |
| Bundles of fibers may form whorls because of their fasicular arrangement in varying planes |
| Nuclei are typically spindle shaped with blunt ends and quite vesicular |
| Mitotic figures are uncommon |
| Rare cells may exhibit nuclear pleomorphism |
| Necrosis and invasion are absent |
| Mucinous degeneration, hyalinization or fibrosis, and adipocytes can be seen, but these features are usually focal and more likely seen in larger lesions |
| Occasionally leiomyomas have a prominent fibroblastic or myxoid component. |