Undifferentiated pleomorphic sarcoma is a common soft tissue sarcoma in the human body, but it is rarely reported in the oral cavity. This article aims to report a case of UPS in the mandible. An 83-year-old female patient was referred to the Department of Oral and Maxillofacial Pathology at the Faculty of Dentistry in Isfahan, Iran, with a complaint of sudden, painless swelling under her removable complete denture, which had grown gradually over three months. The size of the lesion was approximately 5cm, and there were no radiographic defects present. Neoplastic and malignant proliferation of cells, which is necessary for UPS final diagnosis, was present in the H&E microcopy evaluation. Furthermore, immunohistochemical examination proved that the lesion is an undifferentiated pleomorphic sarcoma. Because of the late diagnosis of the disease, the patient died due to lung metastasis before any treatment.  Keywords: Case report; Surgery; Undifferentiated pleomorphic sarcoma; Malignant fibrous histiocytoma.

Introduction: Oral metastases are rare,nevertheless, they must be considered in the differential diagnosis of lesions in patients with a previous history of malignancy or older adults. The clinical signs of oral metastasis typically comprise pain, dysphagia, ulceration, bleeding, and paresthesia. Soft tissue sarcomas tend to affect the extremities and retroperitoneum. The most common metastases in the oral cavity are carcinomas, and sarcomas rarely metastasize to this area. Undifferentiated pleomorphic sarcoma (UPS) is a mesenchymal malignancy that infrequently affects the head and neck site. It shows a male predilection and occurs in all age groups. The lung is the most common area of distant metastasis in undifferentiated pleomorphic sarcoma. Case Report: This report presents a 61-year-old female patient with a painful bluish-purple mass of the posterior right mandibular alveolar mucosa. She had a history of thigh UPS about four years ago. An incisional biopsy was performed, and the specimen was stained with hematoxylin and eosin. Immunohistochemical antibodies for CK, S100, desmin, myogenin, MDM2, SOX10, and caldesmon were negative and focally positive for CD68. Ki-67 index was about 70%. Conclusions: This report aimed to increase awareness of a rare lesion by describing the clinical, histopathologic, and immunohistochemical findings of metastatic undifferentiated pleomorphic sarcoma of the oral cavity.

We describe a case of intracranial malignant fibrous histiocytoma which had infiltrated pons, cerebellum and basal surface of left temporal lobe without any visible mass. The patient presented with a sudden loss of consciousness and vomiting.Clinical findings, laboratory tests, imaging and examination of the cerebrospinal fluid tended to establish the diagnosis of an infectious condition than a malignancy. Without any response to the antibiotics and with a progressive deterioration of neurologic and mental condition, the patient died after 20 days. In the autopsy, histological and immunohistochemical study of the brain revealed the diagnosis of malignant fibrous histiocytoma (MFH).

Malignant fibrous histiocytoma (MFH) is one of the most common types of soft tissue sarcomas in adults. Distant metastases are developed in 30– 40% of patients with MFH, with the most common site being the lung. However, metachronous MFH has not been reported previously in literature. This report describes a case of a 30-yearold man, who had two metachronous thigh tumors, both of which were confirmed to be MFH on histopathology and immunohistochemistry evaluations. A contemporary multidisciplinary approach to therapy including surgery, radiation and chemotherapy was advocated. Two primary sites of MFH raised the possibility of a genetic abnormality that could predispose such a patient to develop multiple primary sites of the same tumor.