Leiomyosarcomas (LMS) 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 tumour and account for ~8% of malignant soft tissue tumours 10.

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

Other sites include

Morphological imaging features would be invariably dependent on 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

May frequently demonstrate cystic foci within. Signal characteristics include 

  • T1: isointense to muscle 
  • T2 non-fat suppressed: intermediate to hypointense to neighbouring fat 
  • T2 FS: predominantly hyperintense 

For a meaningful differential it is necessary to consider site-specific tumours.

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Article information

rID: 10870
Synonyms or Alternate Spellings:
  • Leiomyosarcoma (LMS)
  • Leiomyosarcomas
  • Leiomyosarcomata

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Cases and figures

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    Case 1: uterine leiomyosarcoma
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    Case 2: uterine leiomyosarcoma
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    MR enterography 
    Case 3: of small bowel
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