대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Dedifferentiated Liposarcoma

Radiologic Findings

Chest PA and lateral view show diffuse increased opacity of left lower hemithorax. Left cardiac border is obliterated, and no mediastinal shifting is noted. Enhanced chest CT scans with mediastinal window show a large heterogeneous mass in left lower hemithorax that has two distinct components. Anterior scanty enhanced portion shows soft tissue density with calcification and fat attenuated lesion. The other posterior portion shows heterogeneous enhanced soft tissue density. Left pleural effusion is also noted. Left lower lobe and left lingular segment are partially collapsed due to mass. Coronal and sagittal reconstruction views (first and second figures in this page) show the entire nature of 2 components of mass.
The gross specimen demonstrates a gray-white firm tumor tissue. Cut surface shows focal ill-defined yellowish fat like tissue with multiple foci of necrosis (third figure in this page). Photomicrographs (x40, H-E stain) show interlacing bundles of anaplastic spindled cells (fourth figure in this page) with frequent mitotic figures. Also well-differentiated neoplastic adipose tissues are seen at another photograph (fifth figure in this page), with scattered anaplastic lipoblasts and intervening fibrosis.

Brief Review

Primary sarcomas of the lung constitute only 3% of lung tumors, and liposarcomas are one of the rarest varieties, with only 11 cases reported in the radiologic literature. Although most primary thoracic liposarcomas occur in the mediastinum, sporadic cases involving the lung, pleura, and chest wall have also been described. Possible pathogenetic factors include malignant degeneration of a pulmonary lipoma and pleuropulmonary asbestosis. Primary liposarcoma of the lung has no significant sex predilection, with a reported patient age range of 9-59 years.

Several distinct histologic types of liposarcomas have been described. Well-differentiated liposarcomas resemble lipomas, and myxoid or pleomorphic liposarcomas contain a little or no fat in the most cases. Dedifferentiated liposarcomas have a well-differentiated liposarcoma component juxtaposed with high-grade, nonlipogenic sarcoma component.

Other fat-containing lesions such as pulmonary lipoma, harmatoma, and lipoid pneumonia may be included in the differential diagnosis.

References

1. Ana Gim?ez, Tom? Franquet, Rosa Prats, Pilar Estrada, Jordi Villalba, Silvia Bagu? Unusual Primary Lung Tumors: A Radiologic뻇athologic Overview. Radiographics 2002;22:601-619

2. Munk P, Lee M, Janzen D, Connell D, Logan P, Poon P, Bainbridge T. Lipoma and Liposarcoma: Evaluation Using CT and MR imaging. AJR 1997;169:589-594

3. Strak P, Eber CD, Jacobson F. Primary intrathoracic malignant mesenchymal tumors: pictorial essay. J Thoracic Imaging 1994;9:148-155

Keywords

Lung, Malignant tumor,