Desmoid Tumours in Familial Adenomatous Polyposis: Review of 17 Patients from a Portuguese Tertiary Center

Introduction: Desmoid Tumours (DT) are benign tumours with an estimated incidence of 2-4 per million per year. Between 7-16% of them are associated with Familial Adenomatous Polyposis (FAP) and are mostly parietal or intra-abdominal. They are a challenge in relation to their unpredictable natural course, associated complications and difficult treatment. Aim: The aim of the present study was to review the occurrence, management and follow-up of DT on FAP patients treated consecutively at a tertiary care center. Materials and Methods: A retrospective review of clinical data from patients treated consecutively between 1993 and 2014. Patients' data was gathered from clinical records. Data collection included the following variables: demographic data, genotype, FAP phenotype, data on FAP related surgery, DT diagnosis, location, size and number, DT treatment, patients' status and follow-up data. Results: The study population consisted of 17 patients from 9 families; with a mean age of 41 years, mostly women (59%) and most with a mutation either on codon 232 or 554. Most tumours had an intra-abdominal component (59%) with a mean size of 5cm. Fifteen patients were first treated with pharmacotherapy (Non-steroidal Anti-inflammatory Drugs (NSAIDs) and Tamoxifen). Five patients (29%) underwent surgery, 4 of them for complications of intra-abdominal tumours and 1 patient for abdominal wall tumours. Two patients underwent chemotherapy in relation to aggressive intra-abdominal disease. The mean follow-up time since diagnosis of DT was 123 months. Overall, 2 patients had remission, 11 patients had regression or stabilized disease, and 2 patients had progression. One patient died due to surgical complications. Conclusion: Diagnosis of DT is based on clinical symptoms, without the need for screening, although imaging plays an important role once diagnosis is suspected. The treatment approach is conservative on most patients, leaving surgery for DT related complications. The follow-up of patients with DT is also based on clinical symptoms.