Desmoid tumours exhibit fibroblastic proliferation and arise from fascial or musculoaponeurotic structures. Despite their benign microscopic appearance, and their negligible metastatic potential, the propensity of desmoid tumours for local infiltration is potentially significant in terms of deformity, morbidity and mortality due to pressure effects and obstruction of vital structures and organs. The rarity of desmoid tumours, coupled with the variability in their clinical course, renders these lesions a vexing entity, and makes demonstration of the efficacy of any specific intervention difficult. Failure to recognize the potential for malignant behaviour in this tumour renders desmoids susceptible to inadequate treatment. This distinct pathological entity is reviewed with a specific focus on aetiology and treatment. (C) 2001 Harcourt Publishers Ltd.Desmoid tumours exhibit fibroblastic proliferation and arise from fascial or musculoaponeurotic structures. Despite their benign microscopic appearance, and their negligible metastatic potential, the propensity of desmoid tumours for local infiltration is potentially significant in terms of deformity, morbidity and mortality due to pressure effects and obstruction of vital structures and organs. The rarity of desmoid tumours, coupled with the variability in their clinical course, renders these lesions a vexing entity, and makes demonstration of the efficacy of any specific intervention difficult. Failure to recognize the potential for malignant behaviour in this tumour renders desmoids susceptible to inadequate treatment. This distinct pathological entity is reviewed with a specific focus on aetiology and treatment. (C) 2001 Harcourt Publishers Ltd.