LAUSR

Rationale: During the surgical procedure, endometrial cells can be seeded into the wound edge of the uterine wall, developing into scar endometriosis. Due to the extremely low incidence, estimation of its prevalence is still unavailable. Even rarer might be the scar endometriosis in uterine cavity, to our best knowledge, a situation has not been reported yet. Patient concerns: A 37-year-old woman complained of heavier and prolonged menstruation as well as pelvic pain during menses for more than 4 months. An endometrial cyst in diameter of 6 cm in uterine cavity was revealed by transvaginal ultrasound. Her surgical history was significant for 1 caesarean section and 1 abdominal myomectomy through transverse incision of lower uterine segment. Diagnoses: Space-occupying lesions in uterine cavity, moderate anemia and scar uterus. Interventions: The hysteroscopy was performed and a multilocular cyst full of chocolate-like fluid was removed. Pathological examination confirmed endometrial glands in the removed cyst tissue. Outcomes: During the follow-up visits at 1 and 6 months after surgery, the patient denied any special discomfort. Her postoperative transvaginal ultrasound showed an enlarged uterus with no lesion in uterine cavity. To achieve a better surveillance, a 3-year period of follow-up after surgery at a 6-month interval was suggested. Lessons: Intrauterine endometriosis should be considered in patients of pelvic surgery history with pelvic pain, menstrual disorder, and intrauterine cystic mass.