Giant mediastinal lipoma with bilateral hemithoracic extension in a young woman: a case report

Background Mediastinal lipomas are rare benign tumors that usually remain asymptomatic until they reach a considerable size. Giant mediastinal lipomas can cause progressive respiratory symptoms and present diagnostic challenges by mimicking malignant lipomatous tumors. Case presentation We report a 33-year-old Iranian woman presenting with progressive dyspnea for one year. Chest radiography and contrast-enhanced CT revealed a giant, well-encapsulated fat-density mass in the anterior mediastinum, measuring approximately 214 × 123 × 159 mm, extending to the diaphragmatic level and into the contralateral hemithorax, without invasive features. The patient underwent complete surgical excision via median sternotomy. Intraoperatively, a large encapsulated fatty mass with minimal adhesions and no signs of invasion was identified. Histopathological examination confirmed a benign lipoma composed of mature adipocytes. The postoperative course was uneventful, with complete resolution of symptoms. Conclusions Giant mediastinal lipomas are rare but should be considered in the differential diagnosis of fat-containing mediastinal masses. Cross-sectional imaging plays a pivotal role in diagnosis, while complete surgical resection provides definitive treatment with excellent outcomes.