Last revised by Dr MT Niknejad on 28 Sep 2021

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 10.

Leiomyosarcomas can potentially occur anywhere where there is smooth muscle. Commonly described sites include the following:

Other sites include

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 12
  • 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.

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Cases and figures

  • Case 1: uterine leiomyosarcoma
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  • Case 2: uterine leiomyosarcoma
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  • Case 3: of small bowel
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  • Case 4 : lung metastases from a leiomyosarcoma
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  • Case 5: uterine leiomyosarcoma
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