Fact-sheet: Leiomyosarcoma
Updated on 08/25/2026 at 1:16 PM
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Definition
Leiomyosarcomas are rare malignant neoplasms arising from smooth muscle cells.
They can be considered as the malignant evolution of a leiomyoma.
They account for approximately 8% of malignant soft tissue tumors.
They can potentially be found in any structure containing smooth muscle cells. The main sites of involvement are:
- uterine leiomyosarcoma: the most common
- retroperitoneal leiomyosarcoma: the most frequent extra-uterine location
- leiomyosarcoma - gastrointestinal
More rarely, the following may be found:
- vascular leiomyosarcoma: 5 times more common in venous locations (including leiomyosarcoma of inferior vena cava) than arterial
- cutaneous leiomyosarcoma
Clinical features
Clinical presentation depends on the location of the lesion.
CT
Contrast-enhanced CT acquisition
The lesion:
- is generally heterogeneous
- frequently shows a central area of necrosis
- calcifications are extremely rare
Staging workup to look for secondary lesions.
MRI
The tumor frequently presents cystic foci.
Signal characteristics include:
- T1: isointense to muscle
- T2: intermediate to hypointense relative to adjacent fat
- T2 FatSat: predominantly hyperintense
- T1 with gadolinium: heterogeneous enhancement related to areas of necrosis
Management
The main treatment is oncologic surgery seeking clear margins (R0).
A good prognosis can be achieved for small lesions managed promptly, with a low risk of metastasis.