再问一下uterine polyp

she had a pelvic ultrasound performed, which showed that her endometrium was thin. She had posterior sessile vascular polyp measuring 6 x 5 x 3 mm, as well as an endocervical polyp measuring 2.3 x 1.2 x 1 cm

Her Pap smears are up-to-date and have always been normal.

Doctor recommended hysteroscopic polypectomy.

请问这个polyp的cause是什么？普遍吗？要不要hysteroscopic polypectomy去除？

谢谢