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Year : 2018  |  Volume : 14  |  Issue : 3  |  Page : 481-489

Primary pulmonary synovial sarcoma: A reappraisal

1 Department of Pulmonary Medicine, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India
2 Department of Pathology, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India

Date of Web Publication12-Jun-2018

Correspondence Address:
Pritinanda Mishra
Department of Pathology, All India Institute of Medical Sciences, Bhubaneswar, Odisha
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0973-1482.204883

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 > Abstract 

Synovial sarcoma (SS) is a malignant mesenchymal tumor with variable epithelial differentiation that affects mostly young adults and can arise at any anatomic site. Primary intrathoracic SS is very rare accounting for <0.5% of all lung tumors. Most commonly, it arises from the lung followed by pleura and mediastinum. Primary pulmonary SS (PPSS) affects both sexes equally with no preference for any hemithorax. The morphology, immunostaining properties, cytogenetic features, and management strategy of PPSS are similar to that of soft tissue SS. Histologically, there are two main types of SS – monophasic and biphasic with a feature of poor differentiation seen in both types. Most patients present with large intrathoracic masses with or without ipsilateral pleural effusion. Bone invasion or mediastinal adenopathy is very rare. SS is characterized by a specific chromosomal translocation producing SS18-SSX fusion gene in more than 90% of cases. Identification of this fusion gene remains the gold standard for the diagnosis in the presence of consistent histology and immunophenotype. Multimodality treatment including wide excision, chemotherapy, and radiotherapy is the mainstay of therapy. SS is relatively chemosensitive, and ifosfamide-based regimen showed improved survival in metastatic disease. Generally, SS is considered as high-grade tumors with a poor prognosis. Novel therapies targeted at fusion oncogene, SS18-SSX-derived peptide vaccine, epidermal growth factor receptor, and vascular endothelial growth factor are the future hope in SS. We describe a prototype case and present an elaborate review on primary SS of lung.

Keywords: Immunohistochemistry, primary pulmonary synovial sarcoma, synovial sarcoma, SS18/SSX1 fusion gene

How to cite this article:
Panigrahi MK, Pradhan G, Sahoo N, Mishra P, Patra S, Mohapatra PR. Primary pulmonary synovial sarcoma: A reappraisal. J Can Res Ther 2018;14:481-9

How to cite this URL:
Panigrahi MK, Pradhan G, Sahoo N, Mishra P, Patra S, Mohapatra PR. Primary pulmonary synovial sarcoma: A reappraisal. J Can Res Ther [serial online] 2018 [cited 2022 Jan 25];14:481-9. Available from: https://www.cancerjournal.net/text.asp?2018/14/3/481/204883

 > Introduction Top

Synovial sarcoma (SS) is a spindle cell tumor of mesenchymal origin with variable epithelial differentiations representing 5%–10% of all soft tissue sarcomas and characterized by a pathognomonic chromosomal translocation t(X; 18)(p11;q11). SS usually occurs in deep soft tissue of extremities, especially around the knee in more than 80% of cases; however, any anatomic site including head and neck region, abdominal wall, intra-abdominal and intrathoracic organs, skin, vulva, blood vessel, and neural tissue can be affected.[1],[2],[3] Very rarely SS arises within a joint, and it neither originates nor differentiates toward synovium suggesting the terminology a misnomer.[1],[2] Most patients present between 15 and 35 years and 90% of cases are reported before 50 years of age.[2] Both sexes are equally affected.[1]

Lung is the most preferred site of metastasis in soft tissue SS, and primary pulmonary SS (PPSS) is extremely uncommon. Intrathoracic SS most commonly arises from the lung followed by mediastinum, pleura, esophagus, and heart.[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13] Pulmonary sarcomas constitute only 0.1%–0.5% of all primary lung malignancies. The usual types of primary pulmonary sarcomas are leiomyosarcoma, undifferentiated pleomorphic sarcoma, fibrosarcoma, and SS.[1],[2],[3] In recent times, PPSS is being increasingly diagnosed as a distinct clinical entity due to wider utilization of immunohistochemical staining and cytogenetic analysis.[4],[5],[6],[7],[8],[9],[10],[11],[12],[13] In two recent series, this is reported as the most common type comprising 14.7% and 18% of all primary lung sarcomas and accounts for 6% of SSs in all anatomic locations.[12],[13] We describe a typical case of PPSS in a young man confirmed by cytogenetic analysis and present a detail review summarizing the clinical, pathological, and cytogenetic features, treatment and prognosis of patients in the previously published series.

 > Case Report Top

A 37-year-old male presented with left-sided chest pain, cough, progressive breathlessness, and hoarseness of voice for 2 months. He denied any symptom of phlegm, hemoptysis, dysphagia, or polyarthralgia. He used to smoke occasionally but never drank alcohol. He was thin built and vital parameters were essentially normal. Chest examination revealed diminished breath sound and dull percussion note on left hemithorax with a contralateral shift of trachea. Chest radiograph showed homogeneous opacification of left hemithorax with sparing of costophrenic angle and rightward shift of trachea. Complete hemogram, liver, and renal function tests, serum electrolytes, and coagulation profile were normal except for a mild anemia (hemoglobin 10.2 g/dL). Thoracic ultrasonography suggested a large lung mass with minimal left pleural effusion. Contrast-enhanced computed tomography (CT) of the chest demonstrated a moderately enhancing mixed density mass of size 20 cm × 14 cm with areas of calcification encasing the ascending and descending aorta, compressing left main pulmonary artery, esophagus, and left main bronchus resulting in partial collapse of upper lobe. Minimal left pleural effusion was noted without any mediastinal adenopathy. Right lung appeared normal on CT scan [Figure 1]. Flexible bronchoscopy revealed a fixed left vocal cord, widened carina, and significant extrinsic compression of left main bronchus at bifurcation beyond which the scope could not be negotiated. Bronchial wash cytology was negative for malignant cells. Serological markers for germ cell tumor such as human chorionic gonadotropin (2 mIU/ml) and alpha fetoprotein (2.6 ng/ml) levels were normal.
Figure 1: Computed tomography scan chest showing a large moderately enhancing mixed density lung mass of size 20 cm × 14 cm

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Transthoracic needle aspiration cytology of the mass showed plump spindle cells in short fascicles and scattered, seen adhered to endothelial cell fragments. These cells showed elongated nuclei, granular chromatin, irregular nuclear membrane, and scant cytoplasm, raising the suspicion of a malignant spindle cell neoplasm [Figure 2]a. Histopathological examination of a trucut biopsy specimen showed a cellular tumor composed of spindle cells arranged in long fascicles and herringbone pattern. The latter comprised closely packed, monotonous appearing ovoid to plump spindle cells with scant cytoplasm and indistinct cell borders along with increased mitotic activity of 1–2 per high power field [Figure 2]b suggesting the possibility of SS. The close histological differentials were sarcomatoid carcinoma, malignant peripheral nerve sheath tumor, fibrosarcoma, leiomyosarcoma, spindle cell thymoma, solitary fibrous tumor, and metastatic sarcomas. Immunohistochemically, tumor cells showed strong positivity for vimentin, B-cell lymphoma 2 (Bcl-2) [Figure 2]c, CD99 [Figure 2]d and negative staining for CD34, cytokeratin-7 (CK-7), smooth muscle actin, desmin, and thyroid transcription factor-1 strongly favoring the diagnosis of SS. Real-time reverse-transcriptase polymerase chain reaction (RT-PCR) on paraffin-embedded tissue demonstrated the distinctive SS18-SSX 1 translocation specific to SS [Figure 3]. Thorough clinical and radiological evaluation excluded any extrathoracic primary confirming the diagnosis of PPSS in our case.
Figure 2: (a) Fine-needle aspirate smears show spindle cells in short fascicles and are seen adhered to the endothelial cell fragments (H and E, ×100); Inset (H and E, ×400). (b) Spindle cells are closely packed monomorphic, composed of long fascicles and herringbone pattern. (H and E, ×400).Tumor cells showing B-cell lymphoma 2 (c) and CD99 (d) immunoreactivity (IHC, ×400)

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Figure 3: Gel picture of reverse-transcriptase polymerase chain reaction (RT-PCR) result. Total RNA was extracted from the formalin-fixed, paraffin-embedded tumor tissue and subjected to reverse-transcriptase polymerase chain reaction using SS18 and SSX primers. A DNA molecular weight marker is represented in Lane 1. Lane 2 demonstrates the presence of SS18-SSX1 fusion gene transcripts in the present case. Lane 3 represents the SS18-SSX1 negative control, Lane 4 represents the SS18-SSX1 positive control, and Lane 5 represents nontemplate control

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In view of invasion of mediastinal structures, the tumor was judged inoperable, and chemotherapy with adriamycin (60 mg on day 1) and ifosfamide (2 g on day 1, 2, and 3) was administered. Following three cycles of chemotherapy, patient reported mild symptomatic improvement; however, progression of tumor size was noted in repeat CT scan [Figure 4]. He refused further treatment and lost to follow-up. Possibly, large tumor size, older age, and locally advanced disease contributed to poor response in this case.
Figure 4: Progression of tumor was noted in repeat computed tomography scan

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 > Methods Top

We searched databases such as PubMed and Google Scholar using search phrases “synovial sarcoma lung,” “primary pulmonary synovial sarcoma,” “primary synovial sarcoma lung,” and “primary sarcoma lung” without any time or language restrictions. We also performed a manual screening of all references of the published original studies and review articles to select relevant articles. As on August 4, 2016, we could identify 10 original studies reporting exclusively primary pleuropulmonary or mediastinal SS from 1995 to 2016 and are included in the current review.[4],[5],[6],[7],[8],[9],[10],[11],[12],[13] Besides this, there are many case reports or small case series published describing different aspects of PPSS, some of which are cited here. For the purpose of this review, we excluded the series reporting isolated pleural primary SS.

 > Etiology Top

The exact etiology and specific cell of origin for SS are not known. So far, seven cases of SS developing long after radiation therapy of different primary tumors have been described. Five of these are soft tissue SS whereas two are of primary lung origin. Out of the two cases of PPSS, one is a 20-year-old man who received pulmonary radiation at the age of 4 for metastatic Wilms' tumor and the other one in a 34-year-old female following radioactive iodine therapy for papillary thyroid carcinoma at 20 years of age. Six cases excluding the first one were confirmed by cytogenetic analysis. Five of these seven patients were women and the latency period ranged from 8 to 27 years.[14] Two and half decades ago, one case of SS developing after total hip replacement has been described.[15]

 > Clinical Presentations Top

The clinical characteristics of PPSS are summarized in [Table 1]. Patients with PPSS are usually older than those with soft tissue SS with a median age between 31 and 50 (range 3–84) years. It affects both sexes equally with similar incidence on right and left lungs. The usual symptoms are chest pain, cough, dyspnea, and hemoptysis.[4],[5],[6],[7],[8],[9],[10],[11],[12],[13] Occasional patients may present with pleural or pericardial effusions, hemothorax,[7],[8],[16],[17] recurrent pneumothorax,[18],[19] or endobronchial mass.[20],[21],[22],[23] There is a single report of spontaneous expectoration of tumor tissue presenting as an endobronchial polypoid mass.[23] So far, four cases of PPSS presenting during pregnancy have been reported.[24],[25],[26],[27] Three patients underwent antenatal surgery, and one patient received chemotherapy followed by postnatal lung resection. Three were dead by 13-month postdelivery.[24],[25],[26],[27] Incidental detection of PPSS in asymptomatic individuals is not uncommon.[4],[5],[7],[13],[28] Local recurrence of PPSS is frequent and commonly metastasizes to bone, liver, skin, brain, contralateral lung, spleen, abdomen, and subcutaneous tissue.[4],[5],[6],[7],[8],[9],[10],[11],[12],[13]
Table 1: Summary of clinical, pathological, treatment and follow up details of primary pulmonary synovial sarcoma in previous series

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 > Radiological Features Top

On chest radiograph, PPSS usually presents as a uniform parenchymal mass with well-circumscribed rounded or lobulated borders, pleural mass, or partial or complete opacification of a hemithorax. Contralateral lung usually appears healthy. Ipsilateral pleural effusion is not uncommon. Cavitation, calcification, or lymphadenopathy is usually absent.[4],[5],[6],[7],[8],[9],[10],[11],[12],[13] Most common CT findings are solitary, large, well-circumscribed mass that enhances heterogeneously on contrast with triple attenuation (soft tissue attenuation, a well-enhanced solid portion, and a cystic or necrotic portion) where the nonenhancing hypoattenuation corresponds to the hemorrhagic, necrotic, cystic, or friable portion of the tumor and well-enhancing hyperattenuation area represents the solid tumor tissue.[9],[10],[12],[13] Intratumoral vessels and punctuate calcifications may be seen.[12],[13] Most masses seem to arise from the lung that are usually larger than 7 cm. Often, it may be difficult to ascertain the site of origin due to large tumor size. Bone involvement or mediastinal adenopathy is extremely rare.[1],[4],[6],[12],[13] On magnetic resonance imaging, PPSS shows a similar “triple signal” (bright, dark, and gray) pattern representing tumor, hemorrhage, and necrosis but less vascularity, calcification, and bone invasion compared to soft tissue SS.[10],[12],[13] Fluro-deoxy-glucose positron emission tomography shows variable tumor uptake (standardized uptake value 2.2–17.6)[12] and may be helpful in differentiating two primary tumors in a single patient.[29] The radiologic manifestations of PPSS are no different from bronchogenic carcinoma, metastatic, or other primary lung tumors. However, the young age, absence of mediastinal adenopathy, and bone erosion despite a large size mass favors the diagnosis of a lung tumor other than bronchogenic carcinoma. Because lung is the most common site of metastasis in soft tissue SS and radiological features of primary and metastatic SS are similar, an extrathoracic tumor must be excluded by thorough clinical and radiological evaluation before the diagnosis of PPSS.[9],[12]

 > Pathology Top

The gross, histopathologic, immunohistochemical, and ultrastructural features of primary intrathoracic tumors are identical to those of soft tissue SS. Grossly, the tumor appears well circumscribed and may or may not have a capsule. The tumor size may vary from 0.6 to 31 cm. Cut section appears white-gray or tan with a soft, fleshy to firm or rubbery consistency. Necrosis, hemorrhage, and cystic change are common. Gross calcification may be seen.[4],[9],[11]

Histologically, there are two major categories of SS such as biphasic and monophasic spindle cell type. The other histological variants described are poorly differentiated, monophasic epithelial, calcifying/ossifying, and myxoid types. The monophasic spindle cell type is the most common type of SS in soft tissue and lung. This is composed of relatively small and uniform spindle cells with ovoid, pale-staining nuclei and inconspicuous nucleoli. Cytoplasm is scant, and indistinct cell borders with little intervening collagenous stroma give an appearance of nuclear overlapping. Mitoses are very rare.[2] Features such as dense cellularity, interlacing fascicles, and hyalinized stroma are found in more than 90% cases. Hemangiopericytoma-like pattern, at least focally, is seen frequently.[4],[5],[6],[7],[8],[9],[10],[11],[12],[13] Some tumors have foci of dense fibrosis as a hallmark of previous radiation therapy. Myxoid change is usually focal with alternating hypocellular and more cellular areas and microcyst formation. Mast cells can be abundant.[2]

The monophasic epithelial subtype has a uniformly glandular pattern and practically indistinguishable from adenocarcinoma in the absence of cytogenetic study. Biphasic SS has both epithelial and spindle cell components in variable proportions. The epithelial cells have ovoid nuclei and abundant cytoplasm often arranged in a glandular pattern. These cells can also form solid cords, nests, or rounded clusters. The spindle cells are similar to that in monophasic variety. Majority of PPSSs are of monophasic type.

The poorly differentiated SS has three variants – small cell type, large cell epithelioid type, and a high-grade spindle cell type. Approximately, 20% of cases of SS demonstrate a poorly differentiated morphology.[2],[9],[10],[30] Focal calcification with or without ossification may be seen in one-third of SS. Calcification is more commonly seen in biphasic than monophasic SS and more extensive the calcification better the prognosis. Ossifying SS shows lace-like pattern osteoid or lamellar and trabecular bone formation mimicking osteosarcoma.[2]

 > Immunohistochemistry Top

Approximately, 90% of SS of all histological types express epithelial markers CKs and epithelial membrane antigen (EMA). In monophasic SS, focal expression of CK-positive cells is seen singly, or in cords, nests, or sheets. CK subtypes such as CK7 and 19 are specifically expressed in SS and helpful in differentiating SS from malignant peripheral nerve sheath tumor and Ewing's sarcoma. EMA is expressed more frequently and more diffusely than CK.[2] EMA is also seen in up to 95% of poorly differentiated SS, with keratin expression in approximately 40%.[30] Some cases are EMA+ but CK− or vice versa so that both markers should be used in a complimentary fashion.[2],[30],[31],[32] Diffuse expression of Bcl 2 is usually seen in 98% of cases, and focal or diffuse immunopositivity for CD99 is seen in about 60% cases.[32] S100 protein may be detectable in nuclei or cytoplasm in 40% of all SS and 63% of poorly differentiated SS.[33],[34]

Muscle marker such as calponin is expressed in most SS and useful in differentiating poorly differentiated SS from other small round cell tumors as the later are negative for this marker.[35] Desmin and smooth muscle actin are rarely expressed. Vimentin is present in the spindle cells of SS. CD34 is almost always negative. Transducin-like enhancer 1, a recently described immunomarker, is expressed in 73%–90% of SS of all histological types with a strong and diffuse nuclear staining pattern;[36] however, it is not specific as it is also expressed in other tumors such as peripheral nerve sheath tumors, solitary fibrous tumor, and malignant mesothelioma. Hence, it should only be used along with other specific markers in SS.[37]

 > Ultrastructure Top

The electron microscopic picture of epithelial component of SS is similar to that of adenocarcinoma. Biphasic SS displays glands formation enclosed by continuous external lamina, true epithelial tight junctions, junctional complexes, projecting microvilli, and tonofilaments. Monophasic SS shows cells that are featureless, poorly formed intercellular junctions, short fragments of external lamina, and rare presence of rough endoplasmic reticulum resembling fibroblasts. Short or long cytoplasmic processes may be seen protruding into the intercellular gaps. Zone of epithelial-spindle transition is usually not recognized. Ultrastructural features of poorly differentiated SS are similar to monophasic and biphasic types. Calcifying variants of SS demonstrate intramitochondrial needle-like calcifications.[2],[30],[33]

 > Cytogenetics Top

SS is characterized by a specific translocation t(X;18)(p11.2;q11.2) detected in more than 90% of cases imparting definitional significance. This translocation is usually balanced and reciprocal involving SS18 (formerly SYT) gene on chromosome 18 and one of the genes on X chromosome - SSX1, SSX2, or rarely SSX4 forming SS18-SSX fusion oncogene. Approximately, two-thirds of the cases have a SS18-SSX1 fusion and one-third have a SS18-SSX2 fusion and cases harboring SS18-SSX4 fusion is extremely rare.[38],[39] About 10% of SS may contain both SS18-SSX1 and SS18-SSX 2 translocation in the same tumor.[40] Biphasic SS usually shows a SS18-SSX1 fusion, whereas monophasic SS and poorly differentiated SS may have either the SSX1 or SSX2 fusion.[41] In PPSS, a fusion oncogene is identified in 98% of cases [5],[6],[7],[10],[11],[12],[13] and one case of SS18-SSX4 fusion is reported.[13] Fluorescent in situ hybridization and RT-PCR techniques are commonly utilized on formalin-fixed, paraffin-embedded tissue blocks for identification of the translocation in routine practice. In the absence of typical histomorphology, detection of fusion oncogenes is extremely helpful in differentiating SS from other tumors.[7],[10],[13] If possible, cytogenetic analysis should be done in all suspected cases of SS for definitive confirmation of diagnosis and must be done in cases where histological and immunophenotyping results are inconclusive.

 > Treatment Top

There are no standard recommendations for the management of SS. Wherever feasible, wide surgical resection with tumor-free margins remains the preferred modality of treatment followed by chemotherapy and/or radiotherapy.[42] Most cases of operable PPSS are treated with a lobectomy or pneumonectomy in view of large tumor size. Some cases may be suitable for partial or complete tumorectomy combined with removal of enlarged mediastinal lymph nodes. Surgery is not recommended for tumors that are locally invasive or have metastatic disease. Neoadjuvant and adjuvant chemotherapy may be required in some cases along with surgery.[4],[5],[6],[7],[8],[9],[10],[11],[12],[13]

SS is generally considered as relatively chemosensitive tumor, and treatment with adriamycin alone or in combination with ifosfamide remains the standard chemotherapy in metastatic disease.[42] Randomized control trials and observational studies have shown that ifosfamide-based regimen improves the survival in extremity soft tissue sarcomas.[43],[44],[45],[46],[47],[48],[49],[50] Ifosfamide and adriamycin combination may be used for rapid symptom relief and in patients planned for curative resection of metastases. Radiation therapy alone or combined with surgery is used for achieving excellent local control of disease.[42] SS has a tendency for late recurrence and metastasis; therefore, a longer follow-up exceeding 10 years is recommended.[51] Patients with localized disease have a good chance of cure with surgery and radiotherapy,[52] and negative margins and adjuvant radiotherapy are crucial factors in determining local recurrence-free survival. Overall response rate is about 50% with regimens containing ifosfamide and doxorubicin.[53],[54]

 > Future Therapy Top

Undoubtedly, there is a serious need for an ideal therapeutic agent in SS that is more effective and less toxic. Several novel potential therapeutic targets under research are SS18-SSX fusion oncogene, epidermal growth factor receptor, and vascular endothelial growth factor receptor.[55],[56]SS18-SSX-derived peptide vaccine has been tried as a potential therapy in SS.[57],[58] Pazopanib, an oral vascular endothelial growth factor receptors inhibitor, appears to be effective in leiomyosarcoma and SS.[56] Another molecule Wnt/β-catenin is known to modulate the tumorigenesis and progression of SS consistently, suggesting a future target for the development of novel therapy.[59] NY-ESO-1 is strongly and diffusely expressed in most SS and is a potential therapeutic target.[60]

 > Prognosis Top

In general, SS is considered as a high-grade tumor. Currently, United States National Cancer Institute grading and French Federation of Cancer Centers Sarcoma Group grading are the two widely used systems to grade soft tissue sarcomas. Both are 3-grade systems based on parameters such as tumor location, histology, and amount of necrosis in the former, whereas tumor differentiation, mitotic index, and tumor necrosis are considered in the latter. In the French grading system, parameters such as tumor differentiation and mitotic index are scored from 1 to 3 and a score of 0–2 is given for necrosis. Final grade is done by summing the scores obtained for each of these three parameters. A total score of 2 or 3 is classified as Grade 1, 4, or 5 as Grade 2 and 6–8 as Grade 3 tumors. SS receives a score of 3 for differentiation and automatically falls into high-grade (Grade 2 or 3) tumor.[61] Higher grade tumors are usually associated with metastatic disease with a poor prognosis as 75% of such patients are dead within 2 years of diagnosis.[62] For localized disease, several prognostic factors such as age (>20 or ≥25 or >35 years), tumor size (>5 or >7 cm), invasion of vessels, bone and eurovascular structures, poorly differentiated histology, high mitotic rate (≥10 per 10 high-power fields), presence of tumor necrosis, male sex, and truncal tumor location are found to be predictors of poor survival.[61],[62],[63],[64],[65] Besides this, the type of fusion oncogene (SSX1 or SSX2) present in the tumor has been reported to be of prognostic significance in some earlier studies.[63],[64],[65] These studies reported that patients with SSX1 fusion type have a poorer survival than those with SSX2 transcripts. This finding is refuted in a later study that found no significant association between the fusion types and disease specific and metastasis-free survival in all patients of SS as well as in those with localized and metastatic disease when analyzed separately. Histologic grade of tumor was found to be the most important prognostic factor affecting the survival of patients.[62] Primary intrathoracic SS is more aggressive with an overall 5-year survival rate of 30% compared to 50% in soft tissue SS.[13]

 > Conclusion Top

PPSS is an extremely rare intrathoracic tumor affecting mostly young adults with no sexual bias and equal preference for both lungs. The median age of presentation is slightly greater than that of soft tissue SS; however, the histomorphology, immunostaining properties, molecular genetics, and management strategy are similar to soft tissue SS. Most patients present with large intrathoracic masses without bone involvement or mediastinal adenopathy. There are two main histological types of PPSS – monophasic and biphasic with features of poor differentiation seen in both types. Majority are of a monophasic type. Histopathologically, it may be confused with other pulmonary sarcomas such as leiomyosarcoma, fibrosarcoma, and malignant peripheral nerve sheath tumor mandating cytogenetic analysis to detect SS18-SSX fusion for definitive diagnosis. Treatment is usually multimodal including wide excision, chemotherapy, and radiotherapy. SS is relatively chemosensitive, and ifosfamide-based regimens are the current standard of chemotherapy. In general, these tumors are of high-grade nature with an overall poor prognosis. Novel therapies targeted at fusion oncogene, SS18-SSX-derived peptide vaccine, epidermal growth factor receptor, and vascular endothelial growth factor are the future hope in SS.


We are grateful to Dr. Rekha Pai, Associate Professor, Molecular Pathology Lab, Department of Pathology, Christian Medical College, Vellore, for performing and providing the image of genetic analysis (RT-PCR).

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

 > References Top

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