BACKGROUNDPleomorphic lipoma (PL) is a rare benign mesenchymal tumor occurring predominantly in middle-aged and elderly men. It is typically found in the subcutaneous tissue of the posterior neck, back, and shoulders. There have also been a few reported cases in the face, scalp, and upper extremities. Currently, there is no report on its occurrence in the anterior mediastinum.CASE SUMMARYHerein, we report the case of a 67-year-old woman diagnosed with PL in the anterior mediastinum. The tumor was removed by thoracoscopic surgery. There was no recurrence during the 24-mo follow-up period, and the prognosis was good. Most PL are located on the skin surface. However, they may also occur within the body, even in the mediastinum.CONCLUSIONPL occurring in the anterior mediastinum is rare, and it may be differentiated from other tumors.