A Desmoplastic Fibroblastoma that Developed in the Anterior Mediastinum

Abstract Background:Desmoplastic fibroblastoma (also known as collagenous fibroma) is a benign, slowly growing soft tissue tumor. Most desmoplastic fibroblastomas develop in the limbs, neck, or trunk. A mediastinal origin is quite rare.Case presentation:A 32-year-old female was referred to us for the diagnosis and treatment of an anterior mediastinal tumor. The tumor was 80 mm in the largest diameter and was located on the pericardium. No invasion was evident. She underwent resection of the tumor via video-assisted thoracoscopic resection. The tumor was totally encapsulated, and its pedicle was on the pericardium. The resected specimen was very rigid, making it difficult to remove from the intercostal space. Histologically, the tumor was composed of a paucicellular dense collagenous tissue. Mitosis was rarely observed, and cellular atypia was not evident, suggesting that the tumor was benign. We diagnosed the tumor as a desmoplastic fibroblastoma by morphology and immunohistochemistry.Conclusions:Desmoplastic fibroblastoma of the mediastinum is a rare disease. Preoperative diagnosis is difficult. Early surgical resection is suitable for diagnosis and treatment planning.