|Year : 2018 | Volume
| Issue : 3 | Page : 682-686
Huge primary mediastinal synovial sarcoma fully occupying the right hemithorax
Ahmed Abu-Zaid1, Asma AlNajjar2, Sarah Alotaibi2, Rasha Alshawaf2, Noor Alqeshtaini2, Rwan Alhaidar2, Shamayel Mohammed3, Khaled AlKattan1
1 Department of Surgery, College of Medicine, Alfaisal University; Department of Surgery, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
2 Department of Surgery, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
3 Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
|Date of Web Publication||12-Jun-2018|
Dr. Ahmed Abu-Zaid
College of Medicine, Alfaisal University, P. O. Box 50927, Riyadh 11533
Source of Support: None, Conflict of Interest: None
Primary mediastinal synovial sarcomas are exceedingly uncommon tumors. Herein, we present the case of primary mediastinal synovial sarcoma (monophasic spindle cell-shaped variant) fully occupying the right hemithorax in a 37-year-old woman who presented to clinic with a 2-month history of right-sided chest pain and shortness of breath. Although extremely rare, however, synovial sarcoma should be considered in the differential diagnosis of all monophasic and biphasic spindle cell neoplasms of the mediastinum. Despite molecular testing for (t[x; 18] [p11.2; q11.2]) is characteristically positive in 90% of synovial sarcoma cases, it is not routinely done. Histopathological and immunohistochemical analyses can greatly confirm the diagnosis. Optimal surgical resection is the standard of care. Adjuvant therapy (radiotherapy and/or chemotherapy) is indicated in inoperable advanced disease or unachieved surgical tumor-free surgical margins. Prognosis is poor with a 5-year overall survival (OS) rate of 35.7%. Early diagnosis and prompt appropriate management yield better disease-free and OS rates.
Keywords: Case report, lung, mediastinum, pulmonary, sarcoma, synovial
|How to cite this article:|
Abu-Zaid A, AlNajjar A, Alotaibi S, Alshawaf R, Alqeshtaini N, Alhaidar R, Mohammed S, AlKattan K. Huge primary mediastinal synovial sarcoma fully occupying the right hemithorax. J Can Res Ther 2018;14:682-6
|How to cite this URL:|
Abu-Zaid A, AlNajjar A, Alotaibi S, Alshawaf R, Alqeshtaini N, Alhaidar R, Mohammed S, AlKattan K. Huge primary mediastinal synovial sarcoma fully occupying the right hemithorax. J Can Res Ther [serial online] 2018 [cited 2020 Jul 8];14:682-6. Available from: http://www.cancerjournal.net/text.asp?2018/14/3/682/172137
| > Introduction|| |
Primary mediastinal synovial sarcomas are exceedingly uncommon tumors. Herein, we present a new case of primary mediastinal synovial sarcoma in a 37-year-old woman.
| > Case Report|| |
A 37-year-old woman presented to clinic with a 2-month history of right-sided chest pain and shortness of breath. Patient denied any history of dry/wet cough, hemoptysis, fever, chills, night sweats, decreased appetite, weight loss, bone pain, dysphagia, alcohol intake, smoking, or exposure to radiation. Past medical and surgical histories were unremarkable.
On examination, the patient was vitally stable without signs of respiratory distress or nail clubbing. Cardiorespiratory examination was notable for left-sided tracheal deviation and displaced apical heartbeat. Moreover, there was decreased air entry in the right lung with dullness on percussion.
All laboratory tests including complete blood count, renal, hepatic, coagulation, bone, and tumor marker (CA 125, CA 15-3, and carcinoembryonic antigen) profiles were normal.
Chest radiograph showed complete opacity of the entire right hemithorax with shifting of trachea and heart to the left side [Figure 1].
|Figure 1: Posteroanterior chest radiograph showing: A complete opacity of the entire right hemithorax with shifting of trachea and heart to the left side|
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Whole body contrast-enhanced computed tomography (CT) scan showed a huge, 22.5 cm × 16.4 cm × 16.8 cm, heterogeneous mass fully occupying the right hemithorax [Figure 2]. The mass invaded the mediastinum, pericardium, lower two thirds of esophagus, and right hemidiaphragm. The mass was associated with significant atelectasis of the right lung, small atelectasis seen in the left lower lobe and right-sided loculated pleural effusion. There were few insignificant small lymph nodes seen in the mediastinum and both lung hila. There were no gross findings of distant metastasis elsewhere.
|Figure 2: Coronal (a) and axial (b) contrast-enhanced computed tomography scans showing: A huge, 22.5 cm × 16.4 cm × 16.8 cm, heterogeneous mass fully occupying the right hemithorax. The mass invaded the mediastinum, pericardium, lower two thirds of esophagus, and right hemi-diaphragm|
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Whole body positron emission tomography/CT (PET/CT) scan showed only mild fluorodeoxyglucose (FDG) uptake in the right hemithorax. The skeletal structures were unremarkable. There was no evidence of FDG-avid distant uptake elsewhere.
Thorax needle-core biopsy was done and revealed histopathological features highly suggestive of mediastinal monophasic spindle cell-shaped variant synovial sarcoma. Afterward, patient was scheduled for surgical resection.
Patient underwent right thoracotomy, pleuropneumonectomy and diaphragm resection with repair of diaphragmatic defect using Gore-Tex mesh.
Gross examination of the right pleuropneumonectomy mass weighted 509 g, measured 17 cm × 12 cm × 7 cm, and appeared as friable tan-white tissue.
Microscopically, the mass mostly revealed a spindle cell neoplasm with relatively uniform small cells arranged in densely cellular sheets and fascicles [Figure 3]. The cells displayed void, pale staining nuclei, and inconspicuous nucleoli. The glandular component was very scanty and the epithelial cells had ovoid vesicular nuclei and moderate cytoplasm. Mitosis was infrequent. Five reactive lymph nodes were identified without evidence of metastasis. Surgical margins were not tumor-free. The right diaphragm showed malignancy. The tumor did not infiltrate the underlying lung parenchyma.
|Figure 3: Microscopic examination of resected right pleuropneumonectomy biopsy: (a) The mass mostly revealed a spindle cell neoplasm with relatively uniform small cells arranged in densely cellular sheets and fascicles. The cells displayed void, pale staining nuclei and inconspicuous nucleoli (H and E, magnification power: ×40). (b) The glandular component was very scanty and the epithelial cells had ovoid vesicular nuclei and moderate cytoplasm (H and E, magnification power: ×40)|
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Immunohistochemically, the neoplastic cells stained positive for cytokeratin-7 and epithelial membrane antigen, and negative for S100, desmin, α-smooth muscle actin, and B-cell lymphoma (BCL-2) [Figure 4].
|Figure 4: Immunohistochemical examination of the resected right pleuropneumonectomy biopsy: (a) The neoplastic cells stained positive for cytokeratin 7. (b) The neoplastic cells stained positive for epithelial membrane antigen|
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A final histopathological diagnosis of primary mediastinal synovial sarcoma (monophasic spindle cell variant) involving the right hemithorax was established.
Patient had an uneventful recovery following surgery. Postoperatively, patient received adjuvant radiotherapy. At a 12-month postoperative follow-up, patient was completely asymptomatic and there was no radiological evidence of tumor recurrence.
| > Discussion|| |
Due to its rarity, the diagnosis of primary mediastinal synovial sarcoma is very challenging. According to a recent review, until 2013, only 40 cases of primary mediastinal synovial sarcomas have been documented in the English medical literature. [Table 1] provides a summary of 4 mediastinal synovial sarcoma case reports that were published in the English literature during 2014 and 2015.,,,
|Table 1: Summary of 4 mediastinal synovial sarcoma case reports that were published in the English literature during 2014 and 2015|
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Clinically, the most common presenting signs and symptoms are shortness of breath and chest pain. Other signs and symptoms may include: Cough, hemoptysis, fatigue, weight loss, lung collapse, pleural effusion, pericardial effusion, and superior vena cava obstruction.
On imaging, initial chest radiographs may show well-defined opaque lesions of varying sizes; sometimes associated with tracheal deviation, mediastinal shift, and pleural effusion. CT, magnetic resonance imaging, and PET/CT scans are largely utilized for staging the neoplasm, assessing its resectability, planning the surgical resection and afterward evaluating degree of response to therapeutic interventions.
It is very important for managing surgeons to pay attention to the frequent lack of correlation between the preoperative radiologic picture and the operability of the mediastinal synovial disease. As seen in our case, the tumor was resected completely in spite of the seemingly unresectable status on the preoperative CT scan report: “The mass invaded the mediastinum, pericardium, lower two thirds of esophagus and right hemidiaphragm.” However, intraoperatively, this invasion was incorrect for mediastinum, pericardium, and lower two-thirds of esophagus (as none of these structures were resected), whereas this invasion was correct only for the right hemidiaphragm (as it was needed to be resected and repaired afterward).
There are four histological variants of synovial sarcoma: Monophasic spindle cell, monophasic epithelial, biphasic, and poorly differentiated. Monophasic spindle cell is the most prevalent variant and exhibits fibroblast-like differentiation which makes it difficult to discriminate from the other closely related spindle cell tumors such as hemangiopericytomas, leiomyosarcoma, fibrosarcomas, smooth muscle cell tumors, schwannomas, as well as secondary metastatic sarcomas.
Immunohistochemical staining is necessary to confirm diagnosis and distinguish monophasic spindle cell histological variants of synovial sarcomas from the other closely similar spindle cell neoplasms. Monophasic spindle cell histological variants of synovial sarcoma typically stain positively for epithelial membrane antigen, cytokeratin, BCL-2, O-13, CD99, and vimentin.
Although rarely used, the most crucial method in establishing the definitive diagnosis of mediastinal synovial sarcomas is cytogenetic testing. This is because 90% of such neoplasms exhibit a characteristic reciprocal chromosomal translocation (t[x; 18] [p11.2; q11.2]). Reverse transcriptase-polymerase chain reaction and fluorescence in situ hybridization are two techniques used to identify this translocation.
Molecular testing is not routinely done and unnecessary for diagnosing synovial sarcoma, if such diagnosis was very likely based on the clinical, microscopic, and immunohistochemical results, as it was the case in this presented study. Moreover, testing for this translocation requires advanced cytogenetic infrastructures which may not be available in all pathology laboratories.
Complete surgical resections (R0/R1) of mediastinal synovial sarcomas – whenever technically possible – is the standard of care and has been associated with prolonged disease-free survival (DFS) and OS rates., In 2013, Luo et al. reviewed the surgical outcomes of 21 cases of primary mediastinal soft tissue sarcomas. In this study, patients with complete resection achieved higher statistically significant mean DFS (50.1 months vs. 19.7 months; P = 0.031) and mean OS (49.9 months vs. 24.1 months; P = 0.035) than those patients with incomplete resection. Moreover, in a recent systematic review of 40 cases of mediastinal synovial sarcomas, the complete resection group (R0/R1) achieved a higher statistically significant 5-year OS rate than the incomplete resection group (63% vs. 0%; P = 0.003).
External beam radiation therapy (EBRT) is the most frequent therapeutic modality used in patients with primary unresectable, metastatic and incompletely debulked mediastinal synovial sarcomas. In addition, EBRT has been shown to offer local disease control and OS benefits in such group of patients.
Synovial sarcomas are characterized by their moderate sensitivity to chemotherapeutic regimens comprising doxorubicin and ifosfamide with response rates varying from 30% to 55%.,,,, For extremity synovial sarcomas, one study showed that patients who received adjuvant doxorubicin-cisplatin-ifosfamide chemotherapy achieved a higher statistically significant 5-year disease-specific survival (DSS) (73% vs. 31%; P = 0.001), 5-year metastasis-free survival (62% vs. 34%; P = 0.008) and median time-to-metastasis (25 months vs. 9 months; P = 0.001) than those patients who did not receive adjuvant chemotherapy. Another study by Eilber et al. showed that the 4-year DSS of the ifosfamide-treated patients with extremity synovial sarcomas was 88% compared with 67% for the control patients without chemotherapy treatment (P = 0.01). For mediastinal synovial sarcomas, neoadjuvant chemotherapy with doxorubicin and ifosfamide has been shown to shrink large-sized tumors and consequently facilitate surgical excisions., However, in a recent systematic review of 40 cases of mediastinal synovial sarcomas, patients who received adjuvant chemotherapy (doxorubicin-based and ifosfamide-based regimes) failed to achieve statistically significant 5-year OS rates (46% vs. 24%; P = 0.31) when compared to those patients who did not receive adjuvant chemotherapy. In fact, the definitive role of adjuvant chemotherapy for management of mediastinal synovial sarcomas needs more solid conclusions. In view of the above-mentioned data, in our study, adjuvant chemotherapy was not recommended by the managing multidisciplinary team.
Compared to extremity synovial sarcomas, mediastinal synovial sarcomas carry poorer prognosis as the vast majority of the documented cases of mediastinal synovial sarcomas exhibited local or distant recurrences following optimal surgical debulking. Hence, long-term follow-up is advised.
The prognosis of mediastinal synovial sarcoma is unfortunate with an estimated overall 5-year survival rate of 35.7%. Poor clinical and microscopic prognostic factors include: Age more than 20 years, male, positive disease-containing surgical margins (incomplete resection), tumor size greater than 5-cm in the maximum dimension, neurovascular infiltration, widespread tumor necrosis, high counts of mitotic figures (>10/10 high-power fields), undifferentiated high-grade tumor histology, biphasic variant, SYT–SSX1 reciprocal chromosomal translocation, and presence of distant metastatic foci.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]