Metastatic undifferentiated pleomorphic sarcoma causing intraoperative stroke.

Malignant Fibrous Histiocytoma was historically the most commonly diagnosed soft tissue sarcoma of adults. In 2002, the World Health Organization declassified malignant fibrous histiocytoma as a formal diagnostic entity. They recommended renaming the disease "Pleomorphic Undifferentiated Sarcoma". Current thoughts about the origin of this tumor are being debated. We report a case of a dedifferentiated liposarcoma that metastasized to the lung within one year. The histologic morphology of the metastasis was more aggressive than the primary lesion, and was consistent with a pleomorphic undifferentiated sarcoma. Following surgical resection of the metastatic pulmonary lesion, the patient never fully regained consciousness. He expired the day following his surgery. At autopsy, the patient was found to have died from a massive hemorrhagic stroke involving almost the entire left cerebrum. Tumor emboli from the pulmonary metastasis were seen in the left middle cerebral artery, causing the cerebral infarct. The embolic lesion was consistent with a pleomorphic undifferentiated sarcoma. This case illustrates the evolution that soft tissue sarcomas can undergo as they metastasize and become increasingly undifferentiated, and confirms the surgical risk of resecting such lesions.