RESUMEN
Hemorrhagic pleural effusion (PE) is common in clinical practice. According to the guidelines, the etiological diagnosis of PE should focus on the identification of common diseases. In most cases, the etiology of PE can be determined by clinical history, physical examination, laboratory and imaging examinations, and pleural biopsy or video-assisted thoracic surgery (VAST). We reported a rare case of a 32-year-old woman with recurrent unilateral hemorrhagic pleural effusion (highly correlated with menstrual cycle) and chest pain that was diagnosed as thoracic endometriosis syndrome (TES) by pathological biopsy and immunohistochemistry. Later she underwent surgery combined with hormone therapy. During the follow-up, the right PE decreased, and she had no chest pain. Therefore, women of reproductive age with regular unilateral bloody pleural effusions should be alert to TES.