Introduction
In children, ovarian mature teratomas (OMTs) are usually benign (1). These benign germ cell tumors (GCTs) are characterized by differentiated tissue types originating from 2 to 3 germ cell lineages – the ectoderm, mesoderm and endoderm (2). OMTs represent the most common benign neoplasms among pediatric GCTs, reported in 70% of females under 30 years of age and making up 30% to 50% of all pediatric adnexal lesions (3-10). Even if unilateral OMTs are the most frequent situation at diagnosis, OMT can present as multifocal on ipsi- or contralateral ovaries. Treatment relies on surgery with the aim of obtaining complete tumor resection without recurrence. Nevertheless, the ovarian parenchyma must be preserved when preoperative work-up is consistent with a diagnosis of a benign lesion such as OMT (7). Imaging, particularly MRI plays key role in collecting evidence for the benign nature of the lesion, such as the presence of fat, liquid and calcifications (7, 11). When lesions have large volumes (above 20 cm3 or 8 cm), notable vascularization, intratumoral septations, papillary projections, heterogeneity or solid tissue echogenicity, ascites, or nodal/distant metastasis, the OMT diagnosis should be questioned, and the specialist should be alerted to a potential malignant tumor (2, 6, 9, 11-13). Differential diagnosis also includes other benign lesions, such as epithelial tumors, which account for 30% of benign ovarian tumors (10). The challenge for the decision-making process is that malignant nonsecreting GCTs, such as dysgerminoma or, less frequently, sex-cord stromal tumors, such as granulosa juvenile cell tumors, may present similar features to those of OMTs. Tumor markers (alpha-fetoprotein (AFP), human chorionic gonadotropin (HCG), inhibin B, anti-Müllerian hormone (AMH), calcemia) and hormonal dosages in cases of pseudopuberty or dysmenorrhea are key to ruling out malignant lesions (3, 12, 14, 15). In case of doubt, upfront total oophorectomy (TO) is a secure option, avoiding any spillage of an unrecognized malignant component and avoiding recurrence due to incomplete resection after OSS (14). Ovarian-sparing surgery (OSS) should, however, be highly considered because of the risk of fertility impairment with a cumulative estimated risk of recurrence of 10% to 20% (8, 16).
To better consider the possibility of proposing ovarian-sparing surgery, we report a nationwide cohort of pediatric OMTs and analyze the risk factors for a second event.