Leiomyosarcomas are extremely rare malignant neoplasms that originate from smooth muscle cells and may be considered the malignant counterpart of a leiomyoma. They are classified as a soft tissue tumor and account for ~8% of malignant soft tissue tumors .
Leiomyosarcomas can potentially occur anywhere where there is smooth muscle. Commonly described sites include the following:
- uterus: uterine leiomyosarcoma: most common (account for up to one-third of uterine sarcomas )
- retroperitoneum: retroperitoneal leiomyosarcoma; most common non-uterine site
- stomach : gastric leiomyosarcoma
- esophagus : esophageal leiomyosarcoma
- small intestine: leiomyosarcoma of the small intestine
- liver: hepatic leiomyosarcoma
- bone : primary leiomyosarcoma of bone
- venous structures
- central nervous system: primary intracranial leiomyosarcoma
Other sites include
- spermatic cord: spermatic cord leiomyosarcoma
- pulmonary artery: primary pulmonary artery leiomyosarcoma
Morphological imaging features would be invariably dependent on the site (refer to individual articles). Generally, they tend to be large masses, especially with abdominopelvic lesions.
- generally heterogeneous
- commonly demonstrate central low attenuation representing necrosis
- calcification exceedingly rare
The tumor frequently demonstrates cystic foci. Signal characteristics include
- T1: isointense to muscle
- T2 non-fat suppressed: intermediate to hypointense to neighboring fat
- T2 FS: predominantly hyperintense
For a meaningful differential, it is necessary to consider site-specific tumors.