Sarcoma is rare malignant tumors that develop from mesenchymal cells. Metastasis to the oral cavity is a rare occurrence. Undifferentiated Pleomorphic sarcoma(UPS), formerly known as Malignant fibrous histiocytoma(MFH), is rare spindle cell neoplasm that can have poorly prognosis with metastasis and local recurrence. This report describes a case of a 77-year-old man who was diagnosed with Undifferentiated Pleomorphic Sarcoma of the chest wall and underwent adjuvant radiation therapy after surgical resection. Although there was success of wide excision, two years later, he presented with metastasis to the several organs including tongue. We retrospectively analyzed results of Next Generation Sequencing(NGS), and we figured out RB1 gene mutation. Until now targeted therapy of RB1 gene mutation is not established. Surgeon needs to consider metastatic tumors through identifying patients’ chief complaints and past medical & dental history. We need to research through NGS, and take a step closer to find targeted therapy for tumors.

Undifferentiated pleomorphic sarcoma (UPS) in the mandible region is a rare malignant neoplasm. We encountered the case of a patient who had been diagnosed with deep benign fibrous histiocytoma (DBFH) prior to surgery, but the final biopsy revealed the presence of tumor tissues in the resected margin, which indicated a UPS. Therefore, radiotherapy was conducted post-operatively, but the tumor recurred approximately 3 years later and a second surgery was performed. The difference between the initial and final diagnoses was considered to be due to the characteristics of the tumor, as it involved both benign and malignant components. DBFH and UPS can occur in young women. DBFH can transform to a malignancy and UPS may also appear as a benign tumor during early biopsy. Hence, attention should be paid to diagnosis and treatment methods, and ongoing close observation is required.

Primary sarcoma of the breast is extremely rare and it is a diagnosis of exclusion, notably metaplastic carcinomas and malig-nant phyllodes tumors. We present a case of 53-year old Korean female with undifferentiated pleomorphic sarcoma with CD10 expression. It was a high grade tumor composed of spindle cells, and immunohistochemical analysis revealed negati- vity for cytokeratins and CD34, but focal positivity for actin, diffuse positivity for CD10 and vimentin. These results led to the diagnosis of undifferentiated pleomorphic sarcoma. This case represents a rare variant of primary breast sarcoma which imposes a diagnostic difficulty, and highlights the importance of CD10 expression.

Undifferentiated high grade pleomorphic sarcoma of the thyroid gland is very rare. A 70-year-old woman was referred to our hospital for evaluation of a rapidly growing mass in the right lobe of the thyroid gland. At the first visit, she had no symp-toms. Fine-needle aspiration cytology revealed an atypia of undetermined significance. She revisited our hospital after 17 days. At that time the mass had become more enlarged and she complained of dyspnea. The next day, surgery was performed and the diagnosis was undifferentiated high grade pleomorphic sarcoma of the thyroid. The patient died 119 days after sur-gery.