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Radiology > CHEST
Localized Fibrous Tumor of the Pleura
Article Last Updated: Aug 2, 2007
AUTHOR AND EDITOR INFORMATION
Section 1 of 12  
Author: Moulay Meziane, MD, Head, Section of Thoracic Imaging, Department of Radiology, Cleveland Clinic Foundation
Moulay Meziane is a member of the following medical societies: Radiological Society of North America
Coauthor(s):
Omar Lababede, MD, Consulting Staff, Department of Regional Diagnostic Radiology, Cleveland Clinic Foundation
Editors: Kitt Shaffer, MD, PhD, Director of Undergraduate Medical Education, Associate Professor, Department of Radiology, Cambridge Health Alliance; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; W Richard Webb, MD, Chief of Thoracic Imaging, Professor, Department of Radiology, University of California at San Francisco; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Eugene C Lin, MD, Consulting Staff, Department of Radiology, Virginia Mason Medical Center
Author and Editor Disclosure
Synonyms and related keywords:
LFTP, benign mesothelioma, fibrous mesothelioma, localized mesothelioma, diffuse mesothelioma, malignant mesothelioma, subpleural fibroma, submesothelial fibroma, pleural fibroma, pleural fibromyxoma, solitary fibrous tumor, localized fibrous pleural tumor, lung tumor, pleural tumor, pleural neoplasm, lung cancer, diffuse pleural tumor, localized pleural tumor
Background
Most pleural neoplasms are metastatic in origin. Primary tumors of the pleura can be categorized as diffuse or localized. Diffuse malignant mesothelioma is more common, related to asbestos exposure, and associated with a poor prognosis. Localized mesothelioma, called localized fibrous tumor of the pleura (LFTP), is a less common neoplasm of controversial histogenesis and is unrelated to asbestos exposure.
LFTPs exist in benign and malignant forms. Only rarely is the localized fibrous tumor invasive or does it cause local recurrence after resection. The ratio of benign to malignant tumors is 7:1. The diagnosis of LFTP is important because the tumor is potentially resectable for cure despite its typically large size. In many cases, resection can repeatedly be used to treat recurrence, although usually with increasing difficulty.1
Pathophysiology
The etiology of LFTPs is unknown. No association exists with smoking or asbestos exposure. Although some studies indicate that LFTPs are mesothelial in origin, other reports suggest that they originate from primitive submesothelial mesenchymal cells that are distinct from diffuse malignant mesothelioma. Histologically, the lesions are usually composed of spindle-shaped cells and variable fibrous stroma. Occasionally, oval or polygonal cells may be present. Areas of myxoid degeneration, hyalinization, necrosis, or hemorrhage can be present, especially with large masses. The malignant variant of the LFTP has high cellularity and nuclear pleomorphic mitotic activity. Hemorrhage and necrosis are more frequent in the malignant form. Grossly, an LFTP is a firm soft-tissue mass that is usually larger than 5 cm in diameter. The tumor can arise anywhere in the chest along the pleura, although it appears more commonly from the visceral pleura than it does from the parietal pleura. Lesions can arise from the interlobar fissures. The tumor is often attached by a short pedicle. In 1 study, approximately 50% of tumors were found to have pedicles, and 50% were broad based. Intrapulmonary lesions are reported but are exceedingly rare. LFTPs are solitary in the overwhelming majority of cases; the presence of synchronous lesions is extremely rare.
Frequency
United States
LFTP is a rare disease.
Mortality/Morbidity
Resectability has been shown to be the single most important determinant of the patient's clinical outcome.
Race
No racial predilection has been described.
Sex
Males and females are affected in almost equal numbers.
Age
LFTPs can affect all age groups, but they are most often seen in people who are in their sixth or seventh decade.
Clinical Details
Most patients are asymptomatic, and the lesion is discovered incidentally on chest radiographs. When present, symptoms are usually related to the local mass effect of large lesions or to the associated paraneoplastic phenomena. Symptomatic patients may report dyspnea, cough, or vague chest or shoulder discomfort. Paraneoplastic manifestations have been reported in LFTP, including hypertrophic pulmonary osteoarthropathy and hypoglycemia. Hypertrophic pulmonary osteoarthropathy was reported in 4-35% of patients in some series, and it was found to be associated with LFTP more frequently than with lung cancer. Hypoglycemia has been less frequently associated with LFTP; it has been reported in 5% of patients and could be related to insulinlike growth factor type 2 [IGF-2]. The tumor may become large, occupying much of the hemithorax.
Preferred Examination
Usually, LFTP is incidentally discovered on chest radiographs. Findings from computed tomography (CT) scanning and magnetic resonance imaging (MRI) can suggest the diagnosis of LFTP. However, histopathologic examination is needed for a definitive diagnosis.
Limitations of Techniques
Chest radiographic findings are nonspecific, and the lesion can sometimes be obscured by associated pleural effusion. CT scans and magnetic resonance images may show characteristic findings that are suggestive of LFTP but that are not always pathognomonic. The pleural origin of large lesions can be difficult to detect, especially on chest radiographs and even on CT scans and magnetic resonance images.
Lung Cancer, Non-Small Cell
Mesothelioma, Malignant
Other Problems to Be Considered
Sarcoma
Elevated hemidiaphragm
Loculated pleural effusion
Pleural metastases
Pleural desmoid
Findings
In most patients, the lesion is detected as an incidental finding on chest radiographs.
- The lesion appears on the chest radiograph as a well-circumscribed, homogeneous soft-tissue mass that is related closely to the pleura.
- The lesion can arise anywhere along the pleura and can even be seen in the pulmonary fissures or along the mediastinal or diaphragmatic pleura.
- The margins with lung parenchyma are well defined in most patients.
- In 2% of patients, the lesion is somewhat ill defined; in 2% of patients, the lesion is completely obscured by pleural effusion.
- The angle with the chest wall or mediastinum is either acute or obtuse. The obtuse angle is seen more often in small lesions, indicating the pleural origin of the lesion.
- Large tumors may present as an opaque hemithorax.
- Pleural effusion was reported in 17% of patients, especially in patients with the malignant variant of LFTP.
Degree of Confidence
Chest radiographic findings are nonspecific; however, a change in the position of the lesion with respiration or gravity is particularly suggestive of a pedunculated LFTP.
False Positives/Negatives
The lesion may mimic a mass of parenchymal or mediastinal origin, and large lesions may simulate an elevated diaphragm.
Findings
- Typically, an LFTP appears as a smoothly marginated, soft-tissue–attenuating mass abutting the pleura, with a round or lobulated contour.
- Areas of low attenuation can be seen within the lesion, especially when it is large.
- Unlike other pleural lesions, the angle between the mass and the pleura is most often acute. However, it can be obtuse, especially in small masses.
- The lesion is usually 1.5-25 cm in size.
- A small, ipsilateral pleural effusion can be seen.
- The lesion displaces the adjacent mediastinum and lung parenchyma, resulting in atelectasis.
- On contrast-enhanced CT scans, the lesion enhances more than the soft tissue does, because of its rich vascularization. Nonenhancing areas within the mass are correlated with the presence of necrosis, hemorrhage, or degeneration.
- Calcification is not common, but it can be seen.
- The detection of a pedicle or a change in the lesion's position is suggestive of an LFTP.
- The malignant form of LFTP cannot be confidently differentiated from the benign form by imaging. However, malignant lesions are typically larger than 10 cm and are more likely to be associated with central necrosis and a large pleural effusion.
Degree of Confidence
Manifestations of LFTP on CT scans are usually not pathognomonic, although some CT findings are highly suggestive of the diagnosis.
False Positives/Negatives
Small lesions may mimic primary lung carcinoma; however, a localized fibrous tumor is not associated with metastases or lymphadenopathy.
Findings
- Spin-echo T1-weighted magnetic resonance images predominantly demonstrate low to intermediate signal intensity, and T2-weighted images depict low signal intensity. The low intensity is attributed to the presence of fibrous, hypocellular tissue.
- Foci of increased signal intensity can be seen on T2-weighted images. These foci correspond to the regions of decreased attenuation on CT scans and represent areas of necrosis, hemorrhage, or degeneration.
- Intense enhancement is seen on gadolinium-enhanced T1-weighted images.
Gadolinium-based contrast agents (gadopentetate dimeglumine [Magnevist], gadobenate dimeglumine [MultiHance], gadodiamide [Omniscan], gadoversetamide [OptiMARK], gadoteridol [ProHance]) have recently been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see the eMedicine topic Nephrogenic Fibrosing Dermopathy. The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or magnetic resonance angiography scans. As of late December 2006, the Food and Drug Administration had received reports of 90 such cases. Worldwide, over 200 cases have been reported, according to the FDA. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on thewhites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness. For more information, see the FDA Public Health Advisory or Medscape.
Degree of Confidence
MRI machines can produce multiplanar images, and MRI has superior tissue characterization compared with that of CT scanning; therefore, MRI is helpful in evaluating an LFTP and in defining its pleural origin and extension. After excluding calcifications, the presence of low signal intensity on both T1- and T2-weighted images is highly suggestive of the fibrous nature of the lesion.
Findings
Ultrasonography plays no role in the diagnostic workup of pleural masses. In some patients, however, ultrasonography may be performed to evaluate a pleural effusion or to guide procedures. The fibrous tumor typically demonstrates homogeneous low echogenicity. Associated pleural effusion appears anechoic.
Findings
A case report described the potential use of a fluorodeoxyglucose–positron emission tomography (FDG-PET) scan to evaluate the possibility of malignancy in LFTP. In this report, a high FDG uptake (with a standardized uptake ratio [SUR] of 3.0) was noted in a portion of the mass that exhibited malignant features histopathologically.2 The article suggested that FDG-PET can be helpful to determine preoperatively the presence of malignancy in patients with LFTP, whose prognoses are usually difficult to predict.
Findings
The mass demonstrates hypervascularity with tumoral vessels. Typically, no early venous drainage is seen. The arterial supply is usually derived from the aorta (segmental arteries) and, in some patients, from the internal mammary artery.
Degree of Confidence
The angiographic appearance of the LFTP lesion is nonspecific.
Transthoracic needle biopsy is usually performed as part of the workup in a patient with a pleural mass. However, the diagnostic yield of the transthoracic biopsy is low because of the fibrous nature and hypocellularity of the lesion. The use of cutting biopsy or core biopsy rather than fine-needle aspiration increases the diagnostic yield. In addition, special pathologic techniques, such as electron microscopy and immunostaining (eg, with CD34, bcl-2, CD99) can increase the specificity of biopsy.3 Preoperative embolization can be helpful, especially in large masses.
| Media file 1:
Posteroanterior chest radiograph in a 70-year-old woman who presented with chest discomfort. A well-circumscribed, pleural-based mass is seen in the upper left hemithorax. The angle between the mass and the chest wall is obtuse. The lesion was resected and found to be a benign localized fibrous tumor of the pleura. |
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| Media file 2:
Lateral chest radiograph in a 70-year-old woman who presented with chest discomfort (same patient as in Image 1). |
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| Media file 3:
Chest computed tomography (CT) scans in a 70-year-old woman who presented with chest discomfort demonstrate a pleural, noncalcified soft-tissue mass with smooth, lobulated margins (same patient as in Images 1-2). The mass enhances slightly more than the soft tissue of the chest wall. No evidence of chest wall invasion is seen. |
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| Media file 4:
Posteroanterior chest radiograph shows a mass with sharp, smooth margins in the upper right hemithorax. The angle between the lesion and the chest wall is acute. |
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| Media file 5:
Lateral chest radiograph in the same patient as in Image 4. |
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Posteroanterior chest radiograph shows a large mass in the lower right hemithorax, abutting the mediastinum and the right hemidiaphragm. A portion of the mass margin is obscured by adjacent minimal atelectasis. |
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| Media file 7:
Lateral chest radiograph in the same patient as in Image 6. The described mass is overlying the cardiac shadow. |
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| Media file 8:
Computed tomography (CT) scans of the chest demonstrate a large, somewhat heterogeneous soft-tissue mass in the right hemithorax (same patient as in Images 6-7). A mild mediastinal shift is due to the mass. The mass has well-defined, smooth margins. No evidence of chest wall or mediastinal invasion is noted. |
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| Media file 9:
Posteroanterior chest radiograph in a 78-year-old man reveals a large, homogeneous opacity in the left hemithorax; this is partially obscured by associated pleural effusion. |
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| Media file 10:
Computed tomography (CT) scans of the chest in a 78-year-old man demonstrate an inhomogeneous soft-tissue mass with well-defined margins and a central area of decreased attenuation (same patient as in Image 9). The configuration of the mass suggests that it resides within the major fissure. A small amount of compressive atelectasis is identified in the left upper lobe. No evidence of adjacent rib erosion or extension through the chest wall is seen. Small, bilateral pleural effusions are present. |
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| Media file 11:
Posteroanterior chest radiograph shows that a small mass projects over the left mediastinal margin, inferior to the left hilum. |
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| Media file 12:
Lateral chest radiograph in the same patient as in Image 11 demonstrates the mass overlying the middle mediastinum and deforming the anterior cardiovascular contour. |
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Posteroanterior chest radiograph shows that a retrocardiac mass with smooth margins abuts the medial aspect of the left hemidiaphragm. |
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Lateral chest radiograph in the same patient as in Image 13. A mass with smooth margins abuts the posterior aspect of the left hemidiaphragm. The angle between the mass and the diaphragm is acute. |
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| Media file 15:
Posteroanterior chest radiograph shows a large mass in the lower right hemithorax. The mass abuts the mediastinum and the right hemidiaphragm, mimicking the elevation of the right hemidiaphragm. |
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| Media file 16:
Lateral chest radiograph in the same patient as in Image 15. |
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| Media file 17:
Sonogram of the lower right chest in the same patient as in Images 15-16. A hypoechoic, homogeneous mass (M) is compressing the right diaphragm and displacing the liver inferiorly. |
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| Media file 18:
Contrast-enhanced chest computed tomography (CT) scans in a 51-year-old woman demonstrate a large, heterogeneous mass in the right hemithorax. A significant associated mediastinal shift is present. No chest wall invasion is noted, and a fat plane is separating the aorta and the esophagus from the mass. |
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| Media file 19:
Magnetic resonance images of the chest in a 51-year-old woman, the same patient as in Image 18. Left, T1-weighted image. Right, T2-weighted image. A large, heterogeneous mass is located in the right hemithorax. A significant associated mediastinal shift is seen, with no chest wall or mediastinal invasion. The mass has relatively low signal intensity on the T1-weighted image and has slightly increased signal intensity on the T2-weighted image. |
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T1-weighted chest magnetic resonance images show a low–signal-intensity mass in the posterior aspect of the left hemithorax. |
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T2-weighted magnetic resonance images of the same patient as in Image 20. The noted mass has low signal intensity, with a linear focal area of increased signal intensity (necrosis vs degeneration). |
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| Media file 22:
Chest computed tomography (CT) scans demonstrate a large, heterogeneous mass in the left hemithorax. An associated mediastinal shift is present, with no chest wall invasion. |
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| Media file 23:
Angiography in the same patient as in Image 22. The right hemithorax mass demonstrates increased vascularity. |
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| Media file 24:
Gross pathologic specimen of a resected tumor shows a well-circumscribed, encapsulated mass. |
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Localized Fibrous Tumor of the Pleura excerpt Article Last Updated: Aug 2, 2007
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