- Case report
- Open Access
- Open Peer Review
Computed tomography imaging of subpleural lipoma in two men: two case reports
© Karlo et al; licensee BioMed Central Ltd. 2010
- Received: 22 December 2009
- Accepted: 25 November 2010
- Published: 25 November 2010
Subpleural lipomas are very rare pleural lesions and are often discovered incidentally in asymptomatic patients on conventional radiographs.
We report two cases of subpleural lipomas and describe their imaging characteristics on chest radiographs and computed tomography. We describe the cases of two Caucasian men, aged 77 and 62 years old.
For non-invasive diagnostic investigation, computed tomography enables the identification and quantification of these tumors due to their characteristic fat attenuation.
- Chest Radiograph
- Benign Soft Tissue Tumor
- Pleural Lesion
Lipomas in general are encapsulated, homogeneous, mesenchymal, slow growing tumors that arise in adipose tissue. Although they account for the most common benign soft tissue tumors in humans, intra-thoracic lipomas are considered rare. Subpleural lipomas are parenchymal, fat-containing lesions of the chest, where they arise from the submesothelial layers of the pleura parietalis and may extend into the subpleural, pleural or extrapleural space . Most patients remain asymptomatic and the lipoma is found incidentally on a chest radiograph or a computed tomography (CT) examination. Since only a few cases have been published in the recent literature, we wanted to report two cases of subpleural lipomas with imaging findings from chest radiographs and CT examinations.
Before the implementation of computed tomography in diagnostic medical imaging, most subpleural lipomas were detected during autopsies or incidentally during thoracic surgery. Today, if a pathological pleural or pulmonal lesion is detected on a chest radiograph, CT is a very elegant method to quantify and characterize these lesions. In cases of subpleural lipoma, which shows typical fat attenuation values of approximately -50 to -100HU (Hounsfield units), the diagnosis of a fat-containing tumor of the pleura can be made. However, making the differentiation between well differentiated, malignant liposarcomas and benign lipomas may be challenging on CT images. The typical characteristics of a malignant tumor include invasive growth, inhomogeneous enhancement after intravenous contrast medium application, poor delineation of the lesion and the occurrence of metastases. In the case of lipomas and liposarcomas, even for experienced histopathologists it is a challenge to differentiate between these two tumor entities since the only key finding might be the mitosis rate of the tumor cells . However, CT is able to depict potential invasion of adjacent structures such as the ribs or the soft tissue of the chest wall as well as potential enhancement after the application of contrast agent, although rib erosion has also been reported to occur with benign subpleural lipomas due to the local mass lesion . Benign lipomas usually show no contrast enhancement. The locations of the lipomas presented in this case report are not typical for these tumors, which account for the most common soft tissue tumors in humans and can occur wherever adipose tissue is present; thus, if a solid, well delineated pleural lesion is depicted on a chest radiograph, the differential diagnosis of a subpleural lipoma has to be taken into consideration.
CT should be considered the imaging method of choice to elucidate the location and extent of subpleural lipomas.
Written informed consent was obtained from both patients for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
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