Uterine smooth muscle tumours that cannot be diagnosed unequivocally as benign or malignant should be termed 'smooth muscle tumours of uncertain malignant potential' (STUMP). Since there are no unequivocal morphological and ancillary criteria to differentiate this group of tumours, we present a case of a 49-year-old woman with a combined, benign and borderline lesion, which could have different clinical management strategies, and discuss the diagnostic issues.