[Desmoid tumors in an adolescent girl with familial adenomatous polyposis].

Desmoid tumors (DT) are rare and nonmetastasizing fibroblastic neoplasms, characterized by local invasiveness. They occur sporadically or arise in the context of familial adenomatous polyposis (FAP; 5-10% of cases). Most cases develop sporadically in young adults, but some cases also occur in children. We report the case of an adolescent girl with FAP and DT, and we discuss the therapeutic strategies. An adolescent girl with FAP underwent surgery at the age of 14 years with total proctocolectomy. She had a neo-mutation in the APC gene at codon 1068, which is not usually associated with DT. Three years later, she had painful defecations. Imaging showed two abdominal DT. After a multidisciplinary team meeting, the patient was refused for surgery, and medical treatment with antihormonal agents and nonsteroidal anti-inflammatory drugs was started. Imaging 18 months later showed DT stabilization, but the patient had difficulties to control chronic pains, which required morphine treatment, hypnotic sessions, and transcutaneous electric nerve stimulation. This case highlights the importance of DT screening in patients with FAP, mainly after surgery, regardless of their age and genetic mutation. Progress remains to be made in determining DT risk factors and in developing treatment. DT are still difficult to cure because of their potential for local invasion and local recurrence, and need to be managed by a multidisciplinary team.