Illustration of lung intertwined with DNA, highlighting cancerous growth.

Pulmonary Synovial Sarcoma: A Rare Lung Cancer Explained

Lena Voss in Health & Wellness December 2025 • 4 min read.

"A deep dive into a rare case of primary synovial sarcoma of the lung, its diagnosis, and treatment approaches."

Primary synovial sarcoma of the lung is an exceptionally rare cancer. This article explores a unique case where a previously healthy 47-year-old male presented with a short history of dyspnea. This case highlights the challenges in diagnosing and treating such an uncommon condition.

The patient's symptoms included increasing shortness of breath, left-sided chest pressure, diminished appetite, and unexplained weight loss over three months. Initial chest X-rays revealed a large mass-like density in the left upper lobe, prompting further investigation.

Subsequent CT scans confirmed a significant, heterogeneously enhancing mass in the left hemithorax, measuring 16 x 14 x 16 cm. The mass exhibited neovascularity and focal calcifications, causing mediastinal shift and compression atelectasis. A smaller, separate mass was also identified in the left lung apex. To determine next steps, core biopsies were obtained.

Decoding the Diagnosis: From Biopsy to Molecular Confirmation

Illustration of lung intertwined with DNA, highlighting cancerous growth.

Pathological examination of the biopsy samples revealed a spindle cell neoplasm consistent with synovial sarcoma. Immunohistochemical staining showed a monomorphous spindle cell proliferation positive for TLE-1. Crucially, Cytokeratin, S-100, TTF-1, desmin CD 117, and CD 34 markers were negative, further narrowing the diagnosis.

To confirm the diagnosis, a FISH (fluorescence in situ hybridization) study was performed to detect SYT gene rearrangement. The test came back positive, confirming the diagnosis of synovial sarcoma.

TLE-1 Positive: Indicates the presence of this marker, commonly found in synovial sarcomas.
Cytokeratin, S-100, TTF-1, desmin CD 117, and CD 34 Negative: Rules out other potential types of tumors.
SYT Gene Rearrangement Positive: Confirms the characteristic genetic abnormality in synovial sarcoma.

Pulmonary function testing revealed mild restrictive lung disease, while MRI of the brain was normal. After a complete staging workup, the patient was diagnosed with monophasic synovial sarcoma involving the left hemithorax and lung apex, likely originating from the pleura. The tumor was staged as cT3 or cT4, depending on whether it was considered unifocal or multifocal, with no nodal involvement (cN0) or distant metastasis (cM0). The tumor grade was indeterminate.

Treatment Strategies and Prognosis: Navigating the Challenges

Given the complexity of the case, the patient's treatment plan was developed by the thoracic oncology tumor board. The initial approach involved neoadjuvant chemotherapy with epirubicin and ifosfamide, aimed at reducing the tumor size prior to surgical intervention.

The plan included a subsequent thoracotomy and resection if feasible. The patient tolerated the first cycle of chemotherapy well.

It's important to acknowledge that the overall five-year survival rate for pulmonary synovial sarcoma remains below 50%. Factors such as tumor size (>5 cm), higher grade, male sex, older age, neurovascular invasion, and specific genetic variants (SYT-SSX1) are associated with poorer prognoses. Due to size, surgical resection is often not possible upfront and neo-adjuvant chemotherapy is given.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.rmcr.2018.10.015, Alternate LINK

Title: Pulmonary Synovial Sarcoma

Subject: Pulmonary and Respiratory Medicine

Journal: Respiratory Medicine Case Reports

Publisher: Elsevier BV

Authors: Ankit Gupta, Atul Palkar, Priya Narwal, Ashish Kataria

Published: 2018-01-01

Everything You Need To Know

What exactly is pulmonary synovial sarcoma, and how does it differ from other lung cancers?

Pulmonary synovial sarcoma is a very rare form of cancer that originates in the lung. In the described case, a 47-year-old male presented with symptoms like shortness of breath and weight loss. Diagnosing it involves a combination of imaging techniques like X-rays and CT scans, followed by biopsies and molecular testing to confirm the presence of the SYT gene rearrangement, a characteristic feature of synovial sarcoma. It is important to note that soft tissue sarcomas can occur anywhere in the body, but primary occurrence in the lung is exceedingly rare, adding complexity to diagnosis and treatment.

How is synovial sarcoma accurately diagnosed in the lung, and what role do immunohistochemical markers like TLE-1 play?

The diagnosis of synovial sarcoma in the lung involves a multi-step process. Initially, imaging like chest X-rays and CT scans help identify any unusual masses. A biopsy is then performed, and the tissue sample is examined under a microscope. Immunohistochemical staining is used to check for specific markers; in this case, the sample was positive for TLE-1 but negative for Cytokeratin, S-100, TTF-1, desmin CD 117, and CD 34. The definitive confirmation comes from a FISH study that detects the SYT gene rearrangement, a genetic hallmark of synovial sarcoma. This comprehensive approach is essential to differentiate synovial sarcoma from other spindle cell neoplasms.

What are the typical treatment options for pulmonary synovial sarcoma, and why is a multidisciplinary approach important?

The treatment strategy for pulmonary synovial sarcoma typically involves a combination of chemotherapy and surgery. In the case described, the patient received neoadjuvant chemotherapy with epirubicin and ifosfamide to reduce the size of the tumor before surgery. This approach aims to improve the chances of complete tumor removal during surgery. Radiation therapy might be considered depending on the extent of the disease and the surgical outcome. Given the rarity of this cancer, treatment plans are often developed by a multidisciplinary team, such as a thoracic oncology tumor board, to ensure the best possible outcome.

What is the significance of nodal involvement and tumor grade in assessing the prognosis of pulmonary synovial sarcoma?

The absence of nodal involvement (cN0) and distant metastasis (cM0) at the time of diagnosis is a positive prognostic factor, indicating that the cancer has not spread to regional lymph nodes or distant organs. However, the indeterminate tumor grade and the fact that the tumor was staged as either cT3 or cT4—depending on whether it was considered unifocal or multifocal—suggests a more advanced local disease. The presence of a large mass (16 x 14 x 16 cm) and a smaller separate mass in the lung apex also add complexity. Regular follow-up and monitoring are essential to detect any recurrence or progression of the disease.

Why is the SYT gene rearrangement so important in diagnosing synovial sarcoma, and what does its presence indicate?

The SYT gene rearrangement is a genetic abnormality characteristic of synovial sarcoma. Detecting this rearrangement using a FISH (fluorescence in situ hybridization) study is crucial for confirming the diagnosis. The SYT gene is most commonly involved in a translocation with the SS18 gene, which leads to the formation of a fusion protein. This fusion protein disrupts normal cellular functions and contributes to the development of synovial sarcoma. The presence of the SYT gene rearrangement, along with specific immunohistochemical markers, helps distinguish synovial sarcoma from other similar-looking tumors under the microscope. Further research into the function of the SYT-SS18 fusion protein may lead to the development of novel targeted therapies for this rare cancer.