대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Localized Fibrous Tumor of the Pleura

Radiologic Findings

Chest radiographs and CT scans show a well-defined soft tissue mass arising in the pleural space of the superior portion of the right major fissure. The margin at the junction of the mass with the pleura tapers smoothly. Two differential diagnoses include localized fibrous tumor of the pleura and loculated pleural effusion ("phantom tumor"). However, contrast-enhanced CT scans show mild enhancement of the mass, favoring the possibility of localized fibrous tumor of the pleura.

Brief Review

The term "localized benign (or malignant) fibrous tumor of the pleura (LFTP)" is preferred because histologically these tumors do not contain epithelial cells but derive from a submesothelial mesenchymal cell with fibroblastic differentiation. Localized fibrous tumor of the pleura is rare tumor of mesodermal origin representing less than 5% of all neoplasia involving the pleura. The tumors are discovered incidentally on routine chest radiography, and there is no sex predilection and no evidence of a relationship in asbestos exposure.
Approximately 70 to 80% of these tumors arise from visceral pleura, with the remainder arising from the parietal pleura. A small number are intrapulmonary in location. Most are pedunculated. Large areas of hemorrhage or necrosis are more suggestive of malignant behavior. In Briselli and colleague's review, the best predictor of a good prognosis was the presence of pedicle. Clinically, LFTP occurs in both sexes and in all age groups but predominantly affects persons more than 50 years.
Approximately 50% of patients are asymptomatic, and 40% of symptomatic patients complain chest pain, cough and dyspnea. Extrathoracic manifestations include hypertrophic osteoarthropathy in 4 - 35% and hypoglycemia. Hypoglycemia, noted in less than 5% of patients, is usually associated with very large tumor and is thought to be due to glucose consumption by the mass.
Radiologically, a small to medium-sized tumor appears as a solitary, sharply delineated, often lobulated nodule or mass of variable size from 1 to 39 cm, and forms obtuse angle with the chest wall. Large tumors can appear as opacification of a portion of one hemithorax, and often forms acute angle with the chest wall as the mass is pedunculated or becomes larger than the pleural origin. LFTP exist in the costal compartment of pleura, within an interlobar fissure, along pleural surface of mediastinum, along the diaphragmatic pleura and rarely within the lung parenchyma. These tumors predominate in the middle and lower half of the chest. A pedunculated LFTP can change position and appearance with respiration or with a change in position. Calcification has been reported in 7% of tumors. Pleural effusion was present in 8 - 17 % of cases but is more likely to be associated with malignant tumors than the benign.
On CT scans, LFTPs are well-delineated, often lobulated soft-tissue attenuation mass in close relation to the pleural surface or fissure, and absence of chest wall invasion. The margin at the junction of the mass with the pleura usually tapers smoothly. Calcifications are noted in large tumors and related to the areas of necrosis. The tumors have rich vascularization and shows intense and homogeneous enhancement. Non-enhancing areas on CT scans correspond to necrosis, myxoid degeneration, or hemorrhage within the tumor. Identification of pedicle is a clue to the diagnosis. CT findings that suggest a malignant fibrous tumor include a diameter larger than 10 cm, central necrosis, and ipsilateral pleural effusion.
Local recurrence has been reported in up to 16% of cases, but malignant transformation is unusual.

References

Ferretti GR, Chiles C, Choplin RH, Coulomb M. Localized benign fibrous tumor of the pleura. AJR 1997;169:683-686.

England DM, Hochholzer L, Mccarthy MJ. Localized benign and malignant fibrous tumors of the pleura. A clinicopathologic review of 223 cases. Am J Surg Pathol 1989;13:640-658.

Muller NL. Imaging of the pleura. Radiology 1993;186:297-309.

Kuhlman JE, Singha NK. Complex disease of the pleural space: radiographic and CT evaluation. Radiographics 1997;17:63-79.

Desser TS, Stark P. Pictorial essay: Solitary Fibrous Tumor of the Pleura. Journal of Thoracic Imaging 1998;13:27-35.

Dedrick CG, Mcloud TC, Shepard JO, et al. Computed tomography of localized pleural mesothelioma. AJR 1985; 144: 275-280.

Briselli M, Mark EJ, Dickersin GR. Solitary fibrous tumors of the pleura: eight new case and review of 360 cases in the literature. Cancer 1981;47:2687-2689.

Lee KS, Im JG, Choe KO, et al. CT findings in benign fibrous mesothelioma of the pleura: pathologic correlation in nine patients. AJR 1992;158:983－986.

Keywords

Pleura, Benign tumor,