Fibroid of uterus. Coloured computed tomography (CT) scan showing a fibroid, a benign tumour of the uterus. It is seen at lower centre as a black, round area silhouetted against the uterus (yellow). The tumour is also pressing the bladder seen as a small blue area at bottom centre. Fibroids consist of smooth muscle bundles and connective tissue growing slowly within the uterine wall. Large fibroids, as in this case, exert pressure on the bladder causing discomfort and frequent passing of urine. Small fibroids usually require no treatment whereas large ones may be surgically removed. Hysterectomy may be performed if there are large numbers of fibroids.