Niitsu H, et al. - Researchers aimed at studying the characteristics and surgical treatment of inguinal endometriosis (IEM), which can occur in women of reproductive age via retrospectively reviewing patients who underwent groin surgery at the Hiroshima City Funairi Citizens Hospital between 2004 and 2017. They investigated 2798 patients and identified 28/2798 with the pathological diagnosis of having IEM, with 15, 10, and 3 classified as type I, II, and III respectively. All patients reported a mass (median 20 mm) and/or bulge that mainly occurred at the right inguinal region at presentation. Sixteen patients reported inguinal pain associated with menstruation at presentation. Findings suggested that a complete resection of a hernia sac or hydrocele of Nuck’s canal with subsequent pathological examination is required for women of reproductive age with an inguinal disease because IEM-type I might be underdiagnosed preoperatively.