Advances in the Diagnosis and Management of Neonatal Sarcomas

Epidemiology

The exact prevalence of soft tissue lesions during infancy is not known. However, the estimated annual incidence of all soft tissue sarcomas is 5.9 per 100,000 persons of all age groups and is 1.6 per 100,000 in children less than 1 year of age.⁵ To estimate the incidence of neonatal sarcoma subtypes, we queried the 9 registries from the Surveillance, Epidemiology, and End Results public access database available from 1975 to 2017 for all patients diagnosed at less than 12 months of age.⁶ Of

Diagnostic considerations

The diagnostic workup for a neonatal soft tissue mass typically includes radiographic imaging and either surgical tissue sampling or excision. Radiographic findings are often nonspecific, making it difficult to distinguish benign from malignant tumors. Selecting the optimal imaging modality to evaluate a neonatal mass requires a careful consideration of both logistical and safety concerns specific to this young age group. Ultrasound examination lacks ionizing radiation and has the advantages of

Advances in the management of benign soft tissue tumors

Benign soft tissue tumors constitute an important consideration within the differential diagnosis of neonatal soft tissue masses. Although benign, this group of tumors will usually also require an interdisciplinary team of sarcoma specialists for optimal management. Adequate diagnostic tissue is necessary to differentiate benign from malignant tumors, and the choice and extent of the initial surgery can impact treatment options and outcomes. Therefore, early engagement of an experienced

Desmoid-type fibromatosis

Desmoid-type fibromatosis (aggressive fibromatosis), commonly called desmoids, are also locally aggressive fibroblastic tumors. They are slow growing lesions that often present as a painless infiltrating mass.³⁸ Approximately 30% of desmoid tumors occur in the first year of life. Most cases are sporadic and involve mutations in the β-catenin gene CTNNB1.⁵ However, 2% of desmoid tumors have germline loss of the APC gene causing familial adenomatous polyposis, which is an autosomal-dominant

Extrarenal rhabdoid tumors

Because extrarenal rhabdoid tumors are the third most prevalent malignant sarcoma occurring in neonates (see Fig. 1B, see Table 2), this NRSTS warrants specific review. Rhabdoid tumors are highly malignant pediatric tumors of uncertain etiology. They were first described in the kidney but are now recognized to also arise in other locations. When primary to the central nervous system, they are referred to as atypical teratoid or rhabdoid tumors and, when occurring in nonrenal and non–central

Summary

Because of the rarity and heterogeneity of neonatal sarcomas, performing robust clinical trials specifically in this age group is not feasible. However, as a result of cooperative international networks, our understanding of neonatal sarcomas and therapeutic approaches continue to improve. For example, the use of radiotherapy in neonates was once discouraged owing to the long-term side effects. However, as the result of collaborative trials, we now know that suboptimal local control measures

Recent advances and best practices

Conflicts of interest

The authors have no conflicts of interest to declare.

Ethical statement

The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Acknowledgments

This work was supported by a V Foundation Scholar Award [V2018-028] (MDD).