Uterine polyp. Light micrograph of a section through a polyp (centre) of the endometrium, the mucous membrane that lines the uterus (womb) of the female reproductive system. A polyp is a growth that is usually benign (non-cancerous). No surgical intervention is needed if it causes no symptoms, but some forms can turn malignant (cancerous), and are removed regardless of symptoms. Magnification unknown.