A Challenging Case of Metastatic Intra-Abdominal Synovial Sarcoma with Unusual Immunophenotype and Its Differential Diagnosis. (27th August 2012)

• Record Type: Journal Article
• Authors: Changchien, Yi-Che; Katalin, Uhrin; Fillinger, János; Fónyad, László; Papp, Gergő; Salamon, Ferenc; Sápi, Zoltán
• Other Names: Ma H.-J. Academic Editor.; Soerensen F. B. Academic Editor.
• Is Part Of: Case reports in pathology. Volume 2012(2012)
• Publication Date: 2012-08-27
• Subjects: Pathology -- Periodicals; Pathology; Pathology; Electronic journals; Periodicals; Periodicals; Case Reports; Fulltext; Internet Resources; Periodicals; 616.07
• DOI: 10.1155/2012/786083
• Languages: English
• ISSNs: 2090-6781

Abstract

Abstract : The primary and metastatic gastrointestinal synovial sarcoma is rare with a wide differential diagnosis. It usually expresses cytokeratins EMA, BCL2 with an occasional CD99, and S100 positivity but not desmin. We present a case of metastatic synovial sarcoma with unusual immunophenotype causing diagnostic challenges. The tumor cells showed focal cytokeratin, EMA, and, unexpectedly, desmin positivity. Additional intranuclear TLE-1 positivity and negativity for CD34 and DOG-1 were also identified. A diagnosis of monophasic synovial sarcoma was confirmed by using FISH break-apart probe. RT-PCR revealed the SYT-SSX1 fusion gene. Intra-abdominal synovial sarcoma, either primary or metastatic, with unusual desmin positivity raises the diagnostic challenge, since a wide range of differential diagnoses could show a similar immunophenotype (leiomyosarcoma, desmoid tumor, myofibroblastic tumor, and rarely GIST etc.). Typical morphology and focal cytokeratin/EMA positivity should alert to this tumor, and FISH and RT-PCR remain the gold standard for the confirmation.