[An autopsy case of malignant mesenchymoma of the diaphragm]

An autopsy case of a huge tumor in the right thorax is reported. A 71-year-old man complained of dyspnea and died after three months of hospitalization. The tumor, consisting of a circumscribed mass measuring 24 X 24 X 8 cm and weight 3.7 kg, originated from the right diaphragm and had no metastasis. Histologically, the tumor comprised multiple mesenchymal elements of fibrosarcoma, rhabdomyosarcoma, osteosarcoma and chondrosarcoma, and there was no distinct border between these different components. This tumor fulfills the criterion of malignant mesenchymoma (Stout). The histogenesis of the tumor is discussed with a survey of literature.