Mediastinal malignant fibrous histiocytoma developing from a foreign body granuloma

A patient with mediastinal malignant fibrous histiocytoma (MFH) apparently developing from a foreign body granuloma is reported. A 72-year-old man was admitted to our hospital complaining of generalized fatigue and palpitations. He had undergone surgery for pulmonary tuberculosis 46 years previously. Radiography and computed tomography of the chest showed a round 5-cm mass with marginal calcification in the right side of the anterior mediastinum. The mass was resected completely via median sternotomy. Intraoperative diagnosis of foreign body granuloma was made, based on gauze fragments found in the mass and intraoperative pathologic findings suggesting benign granulation tissue. The postoperative histopathologic diagnosis was myxoid MFH. To our knowledge, mediastinal MFH developing from a foreign body granuloma has not been reported previously.