Malignant Soft Tissue Tumors in Children

Soft tissue masses are frequently seen in children. Although most are benign or reactive, soft tissue sarcomas (STS)-both rhabdomyosarcoma (most common) and non-rhabdo STS, do occur in the extremities. Appropriate evaluation of extremity soft tissue tumors often includes a biopsy as the clinical and imaging features may not be enough to establish a definitive diagnosis. Much needs to be done for improving the treatment of these rare but often devastating sarcomas. Given the small numbers of these cases seen at various centers, collaborative efforts should be made to further our understanding and improve the management of these challenging cases.

Key points

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Soft tissue sarcomas (STS) in children are rare and may have overlapping clinical and imaging features with more common benign tumors and reactive processes, thus making them a diagnostic challenge.
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Soft tissue sarcomas, unlike bone sarcomas, often present as painless masses.
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Soft tissue sarcomas grow in a centrifugal fashion and usually have well defined margins, thus making the differentiation from benign soft tissue lesions challenging.
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Many STS have characteristic chromosomal abnormalities.
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Rhabdomyosarcomas (RMS) are the most common pediatric soft tissue sarcoma in the 0 to 14 age group and account for more than 50% of STS in this age group.
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Alveolar RMS and non-RMS STS are more common in the extremities.
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Treatment of RMS is a combination of chemotherapy, surgery, and radiation (as needed), whereas treatment of non-RMS STS is primarily surgery.