Clinical characteristics
In the present study, the median age of the 31 patients with primary intrathoracic liposarcoma was 45 years (range 20–64 years), which was the same as the age of patients with primary extremity liposarcoma reported by Moreau et al. [4]. However, the mean ages of primary intrathoracic liposarcoma patients reported by the other two studies were 43 and 58 years [2, 5].
We found that the most common initial symptom of intrathoracic liposarcoma was chest tightness (13 cases, 41.9%). Additionally, 6 (19.4%) patients were asymptomatic. However, Burt et al. [3] reported that the most common symptoms of patients with mediastinal liposarcoma were chest pain, dyspnea, wheezing, cough, and weight loss. Dei et al. [6] reported that mediastinal liposarcomas were often asymptomatic until they reached an appreciable size, at which point the symptoms were caused by direct invasion or compression of the heart, great vessels, or lungs.
We also observed that the percentage of patients with tumors located in mediastinum was 77.4% (24 cases), which was much higher than that (37.5%) reported by Hahn and Fletcher [5]. Of the 24 patients with mediastinal liposarcomas, 8 (33.3%) had tumors located in the posterior mediastinum, and 16 (66.7%) in the anterior mediastinum. However, Gladish et al. [7] reported that intrathoracic soft tissue sarcomas were often found in the lungs, mediastinum, pleura, pericardium, heart, and chest wall, whereas Unal et al. [8] found that they were most frequently localized on the chest wall and lungs.
The median tumor diameter was 10.0 cm (range 1.8–32.0 cm). The World Health Organization classification of soft tissue tumors recognizes five categories of liposarcomas: well-differentiated liposarcoma/atypical lipomatous tumor, dedifferentiated liposarcoma, myxoid liposarcoma, pleomorphic liposarcoma, and mixed-type liposarcoma. The most common histological subtype was myxoid liposarcoma (13 cases, 41.9%), followed by well-differentiated liposarcoma (6 cases, 19.4%), whereas dedifferentiated liposarcoma (3 cases 9.7%) was the rarest subtype in the present study. Chen et al. [9] also reported that the most common subtypes were myxoid liposarcoma (34.8%) and well-differentiated liposarcoma (34.8%). Enzinger et al. [10] reported that 40.0%–50.0% of mediastinal liposarcoma was well-differentiated liposarcoma, and 20.0%–30.0% was myxoid liposarcoma.