A 58-year-old female patient came to the antenatal clinic complaining of bloody light-red discharges from the genital tracts. Menopause is 12 years. Gynaecological examination revealed age involution of externalia and vagina; uterine cervix was unchanged, there were scant bloody discharges from uterine cervix, uterus was of normal size; uterine appendages were not palpable; parametria were free. What is the most likely diagnosis?