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  Table of Contents    
CASE REPORT  
Year : 2016  |  Volume : 59  |  Issue : 1  |  Page : 69-71
Sclerosing liposarcoma of the anterior mediastinum: An unusual case


1 Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
2 Department of Pulmonary Medicine and Sleep Disorders, All India Institute of Medical Sciences, New Delhi, India

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Date of Web Publication9-Mar-2016
 

   Abstract 

Liposarcomas are extremely rare in the mediastinum. Patients usually present late due to the compressive effect of the tumor on the adjacent structures. Severity of the symptoms depend mainly on the size of the tumor and the structure it infiltrates. Well differentiated slow growing liposarcomas are the most common ones in the mediastinum followed by dedifferentiated and poorly differentiated ones. These tumors have bad prognosis because of incomplete surgical excision due to its inaccessible location. Hence these patients should be kept under close follow up because of high recurrent rates. Here we are presenting a rare case of anterior mediastinal sclerosing liposarcoma in a 77 year old male.

Keywords: Anterior mediastinum, sclerosing liposarcoma, well-differentiated liposarcoma

How to cite this article:
Arava S, Breta M, Madan K, Nath D, Mehta S, Jain D. Sclerosing liposarcoma of the anterior mediastinum: An unusual case. Indian J Pathol Microbiol 2016;59:69-71

How to cite this URL:
Arava S, Breta M, Madan K, Nath D, Mehta S, Jain D. Sclerosing liposarcoma of the anterior mediastinum: An unusual case. Indian J Pathol Microbiol [serial online] 2016 [cited 2019 Dec 7];59:69-71. Available from: http://www.ijpmonline.org/text.asp?2016/59/1/69/178226



   Introduction Top


Liposarcoma is one of the most common soft tissue sarcomas in adults with a wide anatomical distribution. Common locations include deep soft tissue of the lower limbs and retroperitoneum. [1] Primary anterior mediastinal liposarcoma is an extremely rare clinical entity, constituting <1% of all reported mediastinal tumors. [2] The presenting signs and symptoms are related to tumor size and the direct invasion of contiguous structures. Dyspnea, tachypnea, and wheezing are the most common symptoms, followed by chest pain. [3] Recommended treatment of choice is surgical excision, but recurrence after long-term follow-up is high due to its surgical inaccessibility in a large proportion of cases. [2] Description of this case is of important because of its rarity, high recurrence rate, and poor prognosis among the mediastinal tumors.


   Case report Top


A 77-year-old, never-smoker male patient presented with a history of chest pain, shortness of breath, and dry cough of 2 months duration. Chest pain was predominantly retrosternal and was dull aching in character. The patient had developed insidious onset shortness of breath, easy fatigability, loss of weight (4-5 kg) and dry cough over the last 2 months. There was no history of generalized swelling, hoarseness of voice, dysphagia, wheezing, hemoptysis, or fever. He also complained of neck pain on and off for the last 2 years, which had been diagnosed as cervical spondylosis and the patient had been on conservative management for the same. Pain had worsened over the last 1 year.

On examination, pulse rate was 80/min, respiratory rate was 18/min, and blood pressure was 136/86 mmHg. There was mild pallor, and rest of the general physical examination was unremarkable. On examination of the respiratory system, there was presence of sternal dullness on percussion. Breath sounds were audible equally and normally on both the sides. Examination of the rest of the organ systems was unremarkable.

Posteroanterior chest radiograph [Figure 1] demonstrated mediastinal widening more on the right side with silhouetting of the ascending aorta suggesting the presence of a mass in the anterior mediastinum. The mass appeared to have smooth margins. Both the costophrenic angles appeared normal. Contrast-enhanced computed tomography (CT) scan of the thorax and abdomen demonstrated a large heterogeneous soft tissue attenuating mass lesion measuring 14 cm × 10 cm × 6.7 cm seen in the right anterosuperior mediastinum. Postcontrast administration, no significant intralesional enhancement was observed. The mass showed a few internal fat attenuating areas without any areas of calcification. Anterosuperiorly, the mass appeared to extend between the great vessels, displacing them anteriorly and left laterally [Figure 2]. Right brachiocephalic artery was completely encased by the mass lesion without any vascular compression. Both the lung fields appeared normal. Magnetic resonance imaging scan of the cervical spine showed findings suggestive of advanced cervical spondylosis with degenerative cervical canal stenosis and severe bilateral neural foraminal stenosis at C5-C6 level causing moderate cord compression and focal myelomalacia. Bone scan was essentially normal.
Figure 1: Posteroanterior chest radiograph showing mediastinal widening on the right side with silhouetting of ascending aorta suggestive of a large anterior mediastinal mass. The mass has convex, smooth, well defined, and nonspeculated borders and there is no internal calcification

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Figure 2: Left panel: Computed tomography scan of the thorax (axial sections, mediastinal window) demonstrating a large heterogeneous mediastinal mass which is indenting the proximal airways from anterior aspect and causing slight compression of the right main bronchus. The fat planes with the aorta are lost. Right panel: Coronal reconstruction image of the computed tomography thorax demonstrating a large mediastinal mass with few internal low attenuation areas

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Because of the proximity with and involvement of the major vascular structures, an image-guided biopsy was deemed risky, so thoracotomy and excision biopsy of the mass was performed for histopathological characterization.

Histopathology

On microscopy, the biopsy specimen showed scattered, bizarre, pleomorphic tumor cells exhibiting nuclear hyperchromasia, irregularly condensed chromatin with nuclear membrane irregularity. Some of the tumor cells showed intranuclear inclusions. Occasional multivaculated stromal cells with stellate-shaped nucleus showing scalloping and indentations, morphologically resembling typical lipoblasts were also identified in the background of dense fibrillary and collagenous stroma [Figure 3]. To exclude the remote possibility of malignant nerve sheath tumor, neurofilament immunostaining was carried out which was negative in the fibrillary background. Dedifferentiated areas were not identified. The tumor cells showed nuclear immunopositivity for S 100 protein and negative for CD 56, smooth muscle actin, cytokeratin, and desmin. The proliferative index of the tumor was <2%. Occasional mitosis were noted without any areas of necrosis. With this histology and immunohistochemical (IHC) features, final diagnosis of primary mediastinal sclerosing liposarcoma was made.

Because of the unresectable nature of the primary tumor, the patient was referred for palliative chemotherapy and radiotherapy to the oncology/radiotherapy services.
Figure 3: Sclerosing liposarcoma: (a) Typical stellate lipoblasts (arrow) (H and E, ×40). (b) Fibrillary and collagenous background with entrapped mature fat cells (H and E, ×40). (c) Stellate cells show nuclear immunopositivity for S 100 protein (immunohistochemical). (d) Fibrillary background is negative for neurofilament (immunohistochemical)

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   Discussion Top


Liposarcoma is primarily a disease of adults with equal sex predilection, previous studies have reported that a significant percentage of mediastinal liposarcoma occur in children and young adults. [4] Klimstra et al. found that the average age of patients with anterior mediastinal liposarcoma was 43 years, with 30% between 20 and 35 years of age. Mediastinal liposarcomas are usually detected late when the tumor has attained large size. Common presentations include dyspnea, vague chest discomfort, cough, and constitutional symptoms. [5] Most common cause of these symptoms is due to the compression effects of the tumor on the adjacent structures. [2] Some patients may present with superior vena caval obstructions and as many as 15% of the patients may be asymptomatic and are discovered by routine radiological imaging. Mediastinal liposarcomas arise de novo or from the thymus-related fatty tissue. [5],[6] The behavior of this tumor does not differ from that of other deep-seated liposarcomas. Like other liposarcomas, clinical behavior depends on the histopathological patterns. Well-differentiated forms are of low-grade in nature with rare metastatic potential when compared to that of poorly differentiated ones. Hahn and Fletcher study revealed that most of the mediastinal liposarcomas are of well-differentiated type followed by dedifferentiated and pleomorphic type respectively. Common location in the mediastinum includes anterior followed by posterior and superior mediastinum. [7]

The appearance of mediastinal liposarcoma in CT varies from a predominantly fat-containing mass to a solid mass. Density is related to tumor heterogeneity, the extent of necrosis, and the soft tissue component in the liposarcoma. Pleomorphic types show a markedly heterogeneous internal structures. [6] As IHC stains do not play a significant role in the diagnosis of this tumor. A definitive diagnosis of liposarcoma is made by identifying the stellate shaped lipoblasts on histology in a clinical and radiological setting of a mediastinal soft tissue tumor.

Recommended treatment of choice for all liposarcoma is surgical excision of the tumor. Because of inaccessible location in the anterior mediastinum, resection of the entire tumor is not possible, but debulking will definitely relieve the symptoms. [8],[9] Long-term follow-up of these tumors is very much important because of high recurrence rate. Approximately, 40% of the mediastinal liposarcoma recur after surgery. As the tumor cannot be removed completely, some clinicians prefer radiotherapy and chemotherapy as adjuncts to surgical resection to minimize the recurrence rate. Most commonly recurrences will occur during the first 6 months or it may be delayed for 5-10 years following initial excision. [10]


   Conclusion Top


Anterior mediastinal liposarcoma is very rare with clinical signs and symptoms related to compression of the adjacent structures. Although slow growing, they have poor prognosis related to surgical inaccessibility of complete resection. Debulking will relieve the symptoms. As the recurrent rate is high, a close long-term follow-up is recommended.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
   References Top

1.
Barbetakis N, Samanidis G, Samanidou E, Kirodimos E, Kiziridou A, Bischiniotis T, et al. Primary mediastinal liposarcoma: A case report. J Med Case Rep 2007;1:161.  Back to cited text no. 1
    
2.
Punpale A, Pramesh CS, Jambhekar N, Mistry RC. Giant mediastinal liposarcoma: A case report. Ann Thorac Cardiovasc Surg 2006;12:425-7.  Back to cited text no. 2
    
3.
Currie RA. Mediastinal liposarcoma: Report of a case. Dis Chest 1964;46:489-91.  Back to cited text no. 3
[PUBMED]    
4.
Turgut I, Habli T, Bayram O, Rauf G, Nurettin Y, Akin Y,  et al . A patient with recurrent giant mediastinal liposarcoma. J Thorac Oncol 2007;2:602.  Back to cited text no. 4
    
5.
Klimstra DS, Moran CA, Perino G, Koss MN, Rosai J. Liposarcoma of the anterior mediastinum and thymus. A clinicopathologic study of 28 cases. Am J Surg Pathol 1995;19:782-91.  Back to cited text no. 5
    
6.
McLean TR, Almassi GH, Hackbarth DA, Janjan NA, Potish RA. Mediastinal involvement by myxoid liposarcoma. Ann Thorac Surg 1989;47:920-1.  Back to cited text no. 6
    
7.
Hahn HP, Fletcher CD. Primary mediastinal liposarcoma: Clinicopathologic analysis of 24 cases. Am J Surg Pathol 2007;31:1868-74.  Back to cited text no. 7
    
8.
Thomaz FB, Marchiori E, Guimarães AN, de Magalhães IF, Magalhães FV, Gonçalves LP, et al. Primary mediastinal liposarcoma - Computed tomography and pathological findings: A case report. Cases J 2009;2:8703.  Back to cited text no. 8
    
9.
Grewal RG, Prager K, Austin JH, Rotterdam H. Long term survival in non-encapsulated primary liposarcoma of the mediastinum. Thorax1993;48:1276-7.  Back to cited text no. 9
    
10.
Kara M, Ozkan M, Dizbay Sak S, Kavukçu ST. Successful removal of a giant recurrent mediastinal liposarcoma involving both hemithoraces. Eur J Cardiothorac Surg 2001;20:647-9.  Back to cited text no. 10
    

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Correspondence Address:
Sudheer Arava
Department of Pathology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi - 110 029
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0377-4929.178226

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