Lung
Mesenchymal tumors
Synovial sarcoma
Author: Deepali Jain, M.D.
Topic Completed: 1 September 2012
Minor changes: 16 September 2020
Copyright: 2003-2021, PathologyOutlines.com, Inc.
PubMed Search: pulmonary synovial sarcoma
Table of Contents
Definition / general | Case reports | Microscopic (histologic) description | Positive stains | Negative stains | Molecular / cytogenetics description | Differential diagnosisCite this page: Jain D. Synovial sarcoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lungtumorsynovialsarcoma.html. Accessed March 4th, 2021.
Definition / general
- Rare tumor in lung
- Associated with chest pain, hemoptysis, dyspnea, cough, fever
- Rarely is cystic (Am J Surg Pathol 2010;34:1176)
- 40 - 55% die of disease after 20 years followup, due to metastases to bone, CNS, liver, or invasion of adjacent organs
- Tumors with SYT-SSX2 fusion proteins have 89% 5 year survival vs. 42% for tumors with SYT-SSX1 fusion protein
Case reports
- 45 year old woman with SYT-SSX2 and rapidly progressive course (Arch Pathol Lab Med 2003;127:e201)
- 72 year old white man with poorly differentiated tumor with rhabdoid features (Arch Pathol Lab Med 2003;127:e160)
Microscopic (histologic) description
- Monophasic spindle cells or biphasic with epithelial and spindle cell component
- Monophasic tumors have compact fascicles of hyperchromatic spindle cells with hemangiopericytoma-like areas, often punctuated by small arteries and capillaries in an irregular distribution
- Poorly differentiated tumors have small, round blue cells resembling Ewing sarcoma / PNET
- Rarely rhabdoid features
Positive stains
- TLE1 highly specific (Virchows Arch 2011;459:615)
Molecular / cytogenetics description
- t(X;18)(p11.2;icq11.2)
- Produces either SYT-SSX1 or SYT-SSX2 fusion genes
Differential diagnosis
- Carcinosarcoma: may be primary or metastatic
- Hemangiopericytoma
- Leiomyosarcoma
- Monophasic tumor resembles fibrosarcoma
- Spindle cell carcinoma
