Development of endometriosis and adenomyosis at long-term follow-up of women without abnormal findings at initial ultrasound examination.

Objectives: Investigate if women with symptoms suggestive of endometriosis and no abnormal ultrasound findings at initial examination develop endometriosis lesions or adenomyosis visible at ultrasound examination at long-term follow-up.
Methods: One hundred women were included in this prospective cohort study performed at the Ultrasound Unit, Department of Obstetrics and Gynecology, Skåne University Hospital, Malmö, Sweden. An experienced ultrasound examiner performed transvaginal ultrasound examinations according to the International Deep Endometriosis Analysis (IDEA) group consensus protocol at five-yearlong-term follow-up. Direct and indirect features of adenomyosis were evaluated in accordance with the revised definitions of Morphological Uterus Sonographic Assessment (MUSA).
Results: Endometriosis lesions at follow-up were found in eight women (8%, 95%CI 3.5-15.2%): endometrioma in seven women (7%, 95%CI 2.9-13.9%) and deep endometriosis in four women (4%, 95%CI 1.1-10.0%). Features of adenomyosis were observed in 13 women (13%, 95% CI 7.1-21.2%): direct features in six women (6%, 95%CI 2.2-12.6%) and only indirect features in seven women (7%, 95%CI 2.9-13.9%).
Conclusions: Despite no prior signs of endometriosis and adenomyosis at initial ultrasound examination, endometriosis lesions were found in 8% and direct features of adenomyosis in 6% at long-term follow-up of women with symptoms suggestive of endometriosis and adenomyosis. These findings demonstrate that endometriosis lesions and adenomyosis visible at ultrasound develop during the five years period.