Peutz–Jeghers syndrome was first described by a Dutch physician, Jan Peutz, in 1921. It is an inherited syndrome characterized by intestinal hamartomatous polyps, which can cause obstruction, and mucocutaneous hyperpigmentation. This rare syndrome brings a 15-fold increase in the risk of intestinal as well as gynecologic tumors, especially ovarian cancer. We present a 49-year-old women with a huge adnexal mass and already diagnosed Peutz–Jeghers syndrome. Although the sampling of the endometrium, which was done before the surgery, was normal, cervical adenocarcinoma (adenoma malignum) was diagnosed after the operation, and complementary radical trachelectomy was conducted to complete the therapy. In conclusion, Peutz–Jeghers syndrome patients are at an increased risk of genital tract tumors. It should be kept in mind that a clinical examination could be insufficient to diagnose all the tumoral components of the disease.