Adolescent endometriosis: prevalence increases with age on magnetic resonance imaging scan.

Objective: To evaluate the prevalence on magnetic resonance imaging (MRI) of ovarian endometrioma (OMA) and deep infiltrating endometriosis (DIE) in adolescents presenting with severe dysmenorrhea.

Design: Prospective study.

Setting: Clinic.

Patient(s): A total of 345 adolescents aged 12-20 years referred to the radiologic MRI department unit between September 2019 and June 2020.

Intervention(s): Multiplanar pelvic MRI with cine MRI was performed. Data on the medical history with systematic questioning were collected for each patient before the scan.

Main Outcome Measure(s): Data on the endometriosis phenotypes (OMA and/or DIE), distribution of anatomical lesions, and adenomyosis were evaluated and recorded using a dedicated MRI spreadsheet. Myometrial contractions were systematically reported for each case. The data were correlated with the characteristics of the patients and severity of painful symptoms evaluated using a visual analog scale.

Result(s): The prevalence rates of endometriosis and adenomyosis were 39.3% (121 patients) and 11.4% (35 patients), respectively. Among the adolescents with endometriosis, 25 (20.7%) presented with OMA, and 107 (88.4%) presented with DIE. The odds ratios (confidence intervals) for each pairwise comparison between the age distributions were 2.3 (1.4-3.8) for 15-18 vs. <15 years of age and 3.3 (1.2-8.5) for 18-20 vs. <15 years of age, highlighting a predominance of cases after 18 years of age. Uterine contractions were visualized in 34.4% of cases, with no particular association with endometriosis. No clinical risk factor was identified as being particularly associated with endometriosis. Notably, the visual analog scale score was the same for cases with and without endometriosis.

Conclusion(s): Severe endometriosis phenotypes (OMA and/or DIE) can be observed in adolescents with intense dysmenorrhea, with a linear increase in prevalence over time resulting in a clear predominance after 18 years of age. Endometriosis in adolescents is a challenging clinical problem with a long delay in diagnosis. Imaging can help reduce this delay in young patients with suggestive symptoms.

Clinical Trial Registration Number: NCT05153512.