Desmoid tumours are not common but have a distinct resemblance to fibrosarcomata. Their clinical appearance and progress should be recognised since failure to distinguish them from sarcomata could result in extensive and unnecessarily mutilating operations. Three cases of extra-abdominal desmoid tumours are reported. Two of the patients had tumours arising from multicentric foci in the same limb. The disappearance of the tumours in two patients after the menopause, and the variation in the tumours during the menstrual cycle in the third patient, add weight to the theories about endocrine control.