IntroductionAbnormal uterine bleeding is more frequent in adolescence. Although, most commonly, it has a non-structural etiology, it may be due to any cause described.Clinical caseA 12-year-old adolescent, with no relevant personal history, menarche 1 month before, was observed in the emergency department for severe menstrual bleeding with progressive worsening, and hemodynamic repercussion in need of transfusion support. Physiological ovulatory dysfunction associated with possible previously unknown coagulopathy was considered to be the most likely diagnosis and medical treatment was initiated. Without response, the patient was submitted to sedated observation and uterine aspiration, which ultimately led to the diagnosis of a Burkitt Lymphoma.DiscussionAlthough structural causes, and particularly malignancy, whether gynecological or not, are a rare cause of abnormal uterine bleeding in this age group, they must be considered, thus enhancing the fastest and most appropriate treatment.