Atypical Presentation of Pleomorphic Liposarcoma in the Intrathoracic Extrapulmonary Region

Abstract Liposarcoma (LPS) is a malignant tumor of mesenchymal origin derived from adipocytic lineage. Among its histological subtypes, pleomorphic liposarcoma (PL) represents a rare and highly aggressive variant. PL typically affects the extremities and is most often diagnosed in patients over the age of 50. Its occurrence within the thoracic cavity, especially in young adults, is exceptionally uncommon and frequently associated with pulmonary metastasis. We present the case of a 32-year-old male with no notable medical history who reported symptoms of dyspnea, left-sided posterior thoracic pain, and a non-productive cough. Radiological evaluation revealed a large extrapulmonary, intrathoracic mass originating from the left pleura, causing significant compression of the heart and left lung, leading to atelectasis, though without invasion of the pulmonary parenchyma or chest wall. Initial differential diagnoses included hemothorax, empyema, and pleural effusion based on the mass's location and radiodensity; however, drainage attempts produced only minimal fluid. Thoracotomy performed for presumed pleural decortication unexpectedly revealed a solid mass with localized pleural adhesions. Histopathological examination of the biopsied tissue confirmed a diagnosis of high-grade pleomorphic liposarcoma, characterized by extensive necrosis and the presence of pleomorphic lipoblasts. The patient was initiated on the AIM chemotherapy regimen (adriamycin/doxorubicin, ifosfamide, mesna), and further oncologic care was coordinated through a specialized treatment center. Several aspects of this case were particularly atypical, including the patient’s young age, the intrathoracic extrapulmonary tumor location, the absence of significant pulmonary invasion or distant metastasis, and the lack of identifiable genetic or environmental risk factors. Given the aggressive biology and poor prognosis associated with pleomorphic liposarcoma, treatment typically necessitates a multimodal approach, which can be especially complex due to limited data and guidelines for this rare variant. This case not only illustrates an unusual clinical manifestation of sarcoma but also highlights current therapeutic challenges and underscores the urgent need for research into targeted, subtype-specific treatment protocols.