Abstract
Primary liposarcoma of the lung is extremely rare. To date, only 24 cases have been reported in the English literature. Herein, we present a case of well-differentiated pulmonary liposarcoma that was misdiagnosed as teratoma on positron emission tomography/computed tomography (CT) and contrast-enhanced CT. Radical surgery with left superior lobectomy and mediastinal lymph node dissection were performed. The patient experienced recurrence and distant metastases 33 months after surgery. He was alive at the time of writing this report (36 months postoperatively). To our knowledge, this is the first case report of pulmonary well-differentiated liposarcoma.
Primary liposarcoma of the lung is an extremely rare malignancy, accounting for approximately 0.2% of all pulmonary tumors (1). Lipomatosis and asbestosis may be pathogenic factors (2); According to the World Health Organization Classification of Soft Tissue Tumors (2020 edition), liposarcomas can be divided into five types: well-differentiated, dedifferentiated, myxoid, pleomorphic, and mixed (3); Well-differentiated liposarcoma tumors contain a large amount of fat, usually ≥ 75% of the tumor volume (4). Although well-differentiated liposarcomas have certain imaging characteristics, they still need to be differentiated from other lung tumors, especially those with fatty components such as teratomas, hamartomas, and other mesenchymal-derived tumors (5). Preoperative imaging examination is difficult to correctly diagnose, and the final diagnosis depends on the immunohistochemical results. Immunohistochemistry of well-differentiated liposarcoma was positive for Vimentin, S-100, MDM2, and CDK4 (2). The preferred treatment for primary pulmonary liposarcoma is radical resection and lymph node dissection (2, 4). Well-differentiated liposarcoma was the least invasive of the five pathological subtypes. The 5-year survival rate of well-differentiated liposarcomas is 87.1% (6) and the recurrence rate is 40-50% (7). The median survival time of patients with primary intrathoracic liposarcoma according to the well-differentiated subtypes was 174 months (8).
