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Chapter 5: Leiomyosarcoma and Smooth Muscle Sarcomas
This is a tumor of smooth muscle (or its precursors) and can arise anywhere in the body. Leiomyosarcoma is one of the most common types of sarcoma. Common initial sites for this tumor are the uterus, small intestine or stomach, or the wall of a blood vessel in the abdomen, extremity, or skin. These sarcomas have a highly variable behavior, but when they metastasize they characteristically travel to the lungs and less commonly to the liver, bone, and soft tissues.
Alternative diagnostic termsNone
Common anatomical locationsLower and upper extremities, retroperitoneum, abdomen/pelvis, and trunk.
Pathology commentFascicles of eosinophilic spindled cells with blunt-ended nuclei showing variable pleomorphism; immunolabeling for SMA, desmin, and/or caldesmon.
SourceBridge JA, Dry SM, Fröhling S. Leiomyosarcoma. In: WHO Classification of Tumors Editorial Board. Soft tissue and bone tumors [Internet]. Lyon (France): International Agency for Research on Cancer; 2020 [2024 Dec 29]. (WHO Classification of Tumors Series, 5th ed.; vol. 3). Available from: https://tumourclassification.iarc.who.int/login?redirecturl=%2Fchapters%2F33
For diagnosis or treatmentAny center listed in the Sarcoma Centers Directory »
Patient advocacyAny organization with an established program for patient triage, support, and education. See Patient Advocacy Directory »
Diagnostic-specific organizations:National Leiomyosarcoma FoundationLeiomyosarcomaThe Cynthia Soloman Holmes Foundation
Clinical trialsSARC Clinical Trials – NoneFind clinical trials worldwide »
Common anatomical locationsMost common in the deep soft tissues of the lower extremity.
Pathology commentFascicular proliferation of variably atypical eosinophilic spindle cells, which show mitotic activity; dense inflammatory infiltrate, most often lymphoid or histiocytic/xanthomatous, but the composition is variable; immunopositivity for smooth muscle antigens.
SourceBridge JA, Fletcher CDM, Mertens F. Inflammatory leiomyosarcoma. In: WHO Classification of Tumors Editorial Board. Soft tissue and bone tumors [Internet]. Lyon (France): International Agency for Research on Cancer; 2020 [2024 Dec 29]. (WHO Classification of Tumors Series, 5th ed.; vol. 3). Available from: https://tumorclassification.iarc.who.int/chapters/33.
For diagnosis or treatmentAny center listed in the Sarcoma Center Directory »
Alternative diagnostic termsPending
Common anatomical locationsPending
Pathology commentPending
SourcePending