Undifferentiated Pleomorphic Sarcoma Metastatic to the Orbit

Undifferentiated pleomorphic sarcoma is a malignancy of mesenchymal origin, which was previously known as malignant fibrous histiocytoma. It is known to occur on rare occasion as a primary orbital tumor, but no known cases of metastatic orbital involvement have been reported since 2002, when the reclassification of these tumors took place. The authors report a patient who presented with a metastasis to the left orbit 2 years after undergoing treatment of a high-grade undifferentiated pleomorphic sarcoma of the right thigh. Histopathology of the orbital mass was similar to the primary tumor biopsy prior to neoadjuvant chemotherapy and radiation. The appearance was markedly altered in the subsequent excisional tissue, which showed treatment changes. Immunohistochemistry and genetic testing also supported the metastatic nature of the orbital lesion. The patient's tumor progressed rapidly despite systemic targeted therapy and orbital exenteration was performed. At 2 years follow up, the patient remained without evidence of tumor recurrence in the socket.