Background: Pleomorphic liposarcoma (PLS) is a very rare type of primary pulmonary sarcoma. Clinical data about these tumors are limited, and optimal treatment has not yet been defined. Case Report: A 32-year-old male presented with pain and heaviness over the right chest. Contrast-enhanced computed tomography (CECT) of the chest showed a heterogeneous hypodense pleural-based mass and a mediastinal mass. The patient was treated with chemoradiotherapy, followed by excision and adjuvant chemotherapy. Seven months after completion of treatment, he presented with an abdominopelvic mass and soft tissue peritoneal deposits. The mass was resected, and second line chemotherapy resulted in a partial response. The patient was routinely followed. Six months after completion of the second round of chemotherapy, CECT showed multiple soft tissue deposits in the right lumbar region, right hemipelvis, and presacral region with no evidence of pulmonary disease. Chemotherapy elicited a partial response. Three years from the date of diagnosis, the patient was alive with stable disease. Conclusion: This case is unique because of the rare primary site of PLS presentation and the rare presentation of peritoneal metastasis. Citing such cases would help us to define adequate treatment protocols for this aggressive tumor.