IMMUNOHISTOCHEMICAL EXPRESSION OF TRANSDUCER LIKE ENHANCER OF SPLIT 1 (TLE-1) IN CASES OF SYNOVIAL SARCOMA

Abstract

Objective: To determine the immunohistochemical (IHC) expression of transducer like enhancer of split 1 (TLE-1) in diagnosed cases of synovial sarcoma (SS). Study Design: Cross sectional study. Place and Duration of Study: Department of Histopathology, Armed Forces Institute of Pathology (AFIP), Rawalpindi, Pakistan, from Jan 2017 to Jun 2018. Methodology: In our study, 60 cases of SS diagnosed on hematoxylin & eosin (H&E) morphology, IHC expression of CD99 and epithelial membrane antigen (EMA) were retrieved from archive of Histopathology department AFIP Rawalpindi. Patient’s age, gender, tumor site and histologic type were noted. IHC for TLE-1 was applied and results were recorded. Data was analyzed using SPSS version 22. Results: A total of 60 cases were included in which 33 were males and 27 were females. The male to female ratio was 1.2:1. Mean age of the study patients was 36.6 ± 15 years. SS was found be more common in soft tissues of limbs/ extremities around tendons sheaths (76%); other sites being lungs, head & neck and retroperitoneum. Out of 60 cases of SS, 42 (70%) cases were monophasic, while 15 (25%) and 3 (5%) cases were biphasic and poorly differentiated SS, respectively. A total of 90% samples (n=54) showed immunoreactivity for TLE-1 (p=0.023) out of which 61% samples (n=33) had diffuse (2+) nuclear staining while 21 (39%) showed weak to moderate nuclear staining for TLE-1. However, 6 (10%) cases did not show nuclear staining for TLE-1. Conclusion: TLE-1 was found to be a novel marker which was extremely helpful in diagnosis of SS, especially in cases where diagnostic challenge arises when other spindle cell neoplasms are considered in the differential diagnosis and in laboratory set ups where advanced facilities of molecular testing by fluorescent in situ hybridization (FISH) is not available.

Keywords

• immunohistochemistry
• spindle cell sarcomas
• synovial sarcoma