Liposarcoma of pleural cavity with recurrence as malignant fibrous histiocytoma

The case of a 54-year-old male, with a massive right pleural liposarcoma weighing over 3200 g, is presented. The tumor was found by light and electron microscopy to be of well-differentiated and pleomorphic subtypes, and it apparently represents the sixth reported case of liposarcoma primary to the pleura. Two years after excision of the primary tumor, it recurred as a neoplasm with histologic and ultrastructural features characteristic of malignant fibrous histiocytoma. The histogenetic and pathologic implications of the above findings are discussed, and the literature regarding intrathoracic liposarcoma and malignant fibrous histiocytoma is reviewed.