Giant Mediastinal Mature Cystic Teratoma During Pregnancy: A Case Report

Mature mediastinal teratomas are rare, benign germ cell tumors that are typically asymptomatic. Their presentation during pregnancy is extremely uncommon, and acute manifestations with respiratory compromise are exceptional. We report the case of a 19-year-old primigravida at 16.5 weeks of gestation presenting with progressive dyspnea, severe pleuritic pain, and a massive pleural effusion. Imaging revealed a giant anterior mediastinal mass. Tumor markers, including alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (β-hCG), were elevated, raising concern for malignancy. Due to the critical mass effect on maternal respiratory function, urgent surgical resection via left thoracotomy was performed. Histopathology confirmed a mature cystic teratoma. The patient recovered well, continued her pregnancy under specialized surveillance, and delivered at 37.1 weeks of gestation without complications. This case highlights that timely surgical intervention in a multidisciplinary setting is the definitive treatment for symptomatic mediastinal teratomas in pregnancy.