Target therapy with celecoxib in pediatric recurrent desmoid tumors. A case report

Summary

We present a pediatric case of a mediastinal desmoid tumor in which CTNNB1 mutation was detected, a genetic mutation which predicts sensitivity to celecoxib, a COX-2 inhibitor.We present the case of a 6 year old girl with a recurrent mediastinal desmoid tumor.Surgical resection was conducted due to the high risk of hemodynamic impairment.The histopathological study confirmed the diagnosis of desmoid-type fibromatosis.Close follow-up was performed with thoracic MRI, identifying tumor recurrence at 18 and 24 months after diagnosis, which are surgically resected. A somatic mutation in CTNNB1 (c.121A>G; p.T41A) is identified. Target treatment with celecoxib and sorafenib was administered. Secondary effects associated to sorafenib appear and treatment with sorafenib is interrupted. Celecoxib in monotherapy is maintained. After 2 years of treatment, the patient remains in complete remission. The generation of therapeutic guidelines is complex. Spontaneous regression has been described in a 20-30% of the cases, recommending “watch and wait strategies”.In symptomatic cases or with risk of functional impairment, surgical or systemic treatment must be considered. If there is a known molecular target such as CTNNB1,target therapy with NSAIDs (i.e. celecoxib) is recommended. Our case demonstrates the efficacy of celecoxib in monotherapy. The identification of molecular targets through genetic study is highly advisable,especially in unresectable, progressive or recurrent desmoid tumors.Treatment with celecoxib in monotherapy could be a secure and effective therapeutic alternative