Sporadic desmoid tumors in the pediatric population: A single center experience and review of the literature.

BACKGROUND/PURPOSE: We present our long experience with desmoid tumors in children.

METHODS: Data were retrospectively collected from 17 children/adolescents treated for sporadic desmoid tumors at a tertiary pediatric hospital in 1988-2016. There were 10 girls and 7 boys aged 1-17years. Tumor sites included head and neck, trunk, extremity, and groin. Eight patients underwent radical resection, with complete remission in 7 and local relapse in one which was treated with chemotherapy. Four patients underwent incomplete surgical resection, three with adjuvant chemotherapy. Five patients underwent biopsy only and chemotherapy. Two of the 9 chemotherapy-treated patients also had intraarterial chemoembolization. Chemotherapy usually consisted of vincristine and actinomycin-D with or without cyclophosphamide or low-dose vinblastine and methotrexate. Two patients also received tamoxifen.

RESULTS: After a median follow-up of 3.3years, 10 patients were alive in complete remission, 5 had stable disease, and 2 had reduced tumor size. Five-year overall survival was 100%, and event-free survival, 87.5%. Ten were screened for CTNNB1 mutations. CTNNB1 gene sequencing yielded mutations in 5/10 samples tested: 3 T41A, 2 S45F. There was no association of CTNNB1 mutation with clinical outcome or prognosis.

CONCLUSION: Pediatric desmoid tumors are rare, with variable biologic behavior and morbidity. Treatment requires a multidisciplinary approach.

LEVEL OF EVIDENCE: LEVEL IV, treatment study.