Dedifferentiated liposarcoma of the pleura: a case report

Introduction

Liposarcoma is a common adult sarcoma representing 20% of soft tissue sarcomas, it is mainly localized in soft tissues and at the retroperitoneal level. The pleural localization is exceptional. Dedifferentiated liposarcoma is a rare subtype of liposarcoma with a poor prognosis.

Takanami and Imamura reported the first case of dedifferentiated liposarcoma of pleural (DDLP) in 2005 (1). In the published literature, only three cases have been described. Herein, we present a patient with the dedifferentiated liposarcoma variant of primary pleura liposarcoma. We present this case in accordance with the CARE reporting checklist (available at https://jxym.amegroups.com/article/view/10.21037/jxym-24-12/rc).

Case presentation

A 42-year-old man with a history of chronic smoking weaned 11 years ago, with no notion of contact asbestosis. He has been experiencing pain in his right chest for 4 months. The clinical examination is poor, and the laboratory assessment is unremarkable. The chest X-ray shows a homogeneous opacity occupying almost the whole of the right hemithorax (Figure 1). The computed tomographic (CT) thoracic shows a large well-limited right mass with three components (tissue, fat and calcification), measuring 17.9 cm × 14.8 cm responsible for a repression of the mediastinum to the left side with moderate ipsilateral pleural fluid effusion (Figure 2). A scan-guided biopsy was performed which came back inconclusive. A right posterolateral thoracotomy was performed objectifying a multinodular mass at the expense of the right parietal pleura, the tumors were slightly adherent to the lung, no invasion of the chest wall and diaphragm was found, the resection was radical, the total weight of the resected mass was 1,584 g (Figures 3,4). The histological examination was in favor of a grade 2 dedifferentiated liposarcoma from the FNCLCC (Fédération National des Centres de Lutte Contre Le Cancer) and confirmed by immunohistochemistry where the CD34 and MDM2 and CDK4 markers came back positive (Figure 5). Postoperatively, the patient recovered with no major complication. Adjuvant post-operative radiotherapy of the pleura was decided. The patient has been followed up for one year with no signs of recurrence. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Figure 1 Chest X-ray showing a large homogeneous opacity in the right hemithorax.

Figure 2 Computed tomographic scan of chest, showing a mass measuring 17.9 cm × 14.8 cm in the right pleural cavity with inhomogeneous tissue densities and areas of calcification.

Figure 3 Perioperative illustrations showing the pleural tumor. The tumor is attached to the parietal pleura.

Figure 4 Macroscopic appearance of the pleural mass.

Figure 5 Microscopic view of the tumor. (A) Histology showing a component of well-differentiated liposarcoma juxtaposed with areas of high-grade non-lipogenic spindle cell sarcoma (hematoxylin and eosin staining); (B) positive immunohistochemical staining for CD4; (C) positive immunohistochemical staining for MDM2. Magnification: ×200.

Discussion

Liposarcoma is a malignant mesenchymal tumor which is localized mainly in soft tissues and retroperitoneal. The pleural location is exceptional. Four histological subtypes are described which reflect the degree of differentiation: well differentiated liposarcoma, myxoid or round cell liposarcoma, pleomorphic liposarcoma and dedifferentiated liposarcoma (2,3).

DDLP is an extremely rare tumor, generally occurs between the ages of 50 and 70 years. The clinical signs is asymptomatic for a long time, it becomes symptomatic only when the tumor takes on important dimensions characterized by the presence of chest pain, cough and dyspnea. The CT scan shows a well-defined inhomogeneous mass with the presence of tissue density, fat and calcifications, as the case of our patient, but in some cases, it may be possible to not find fatty components in the tumor. No radiological description of magnetic resonance imaging (MRI) for DDLP has been described (1,4).

Differential diagnoses include solitary fibrous tumor of the pleura, mesothelioma, bronchogenic carcinoma, benign fatty tumors, abscess (5).

Histologically, DDLP is a malignant mesenchymal tumor that can appear straight away as a high-grade lipomatous malignancy. Or it can also appear as a result of a sarcomatous transformation of a pre-existing lipoma. It is defined by the association of well-differentiated liposarcoma areas and a non-lipogenic sarcoma, usually with an abrupt transition, although in some cases can be gradual or even intermixed. It and can be confirmed by the positivity of MDM2 and CDK4 in immunohistochemistry (2).

The prognosis of dedifferentiated liposarcoma is associated with a high risk of local recurrence with a low potential for metastasis. It depends on the degree and extent of differentiation (1).

Due to the rarity of the tumor no specific therapeutic consensus for DDLP has been established; but in general, the treatment for pleural liposarcomas is essentially based on radical resection of the tumor followed by adjuvant radiotherapy (3).

This case shows the importance of putting DDLP in the differential diagnosis of large inhomogeneous pleural tumors.

Conclusions

We report a case of DDLP which is an extremely rare tumor. The clinical and radiological characteristics are still nonspecific. The diagnosis is essentially based on histological examination and immunohistochemistry. In the time being, no specific treatment is established; radical resection followed by radiotherapy remains the treatment of choice.

Acknowledgments

Funding: None.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://jxym.amegroups.com/article/view/10.21037/jxym-24-12/rc

Peer Review File: Available at https://jxym.amegroups.com/article/view/10.21037/jxym-24-12/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jxym.amegroups.com/article/view/10.21037/jxym-24-12/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

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