Primary pulmonary undifferentiated pleomorphic sarcoma: A rare malignant lung tumor.

Undifferentiated Pleomorphic Sarcoma (UPS) is a common soft tissue sarcoma that can develop in various organs, but lung involvement is usually due to metastasis. UPS originating primarily in the lungs is called primary pulmonary undifferentiated pleomorphic Sarcoma (PPUPS) and is exceptionally rare. It is a high-grade pleomorphic neoplasm with no identifiable lines of differentiation. Thus, it is essentially a diagnosis of exclusion that requires extensive clinical, radiographic and histopathological evaluation. Herein we report the case of a 49-year-old gentleman who presented with anemia and weight loss and was found to have a large right lung mass. The lesion was diagnosed as PPUPS after detailed histopathological, immunohistochemical and molecular analysis and exclusion of a possible extrapulmonary origin.