Synovial sarcoma with overwhelming glandular (adenocarcinoma-like) component: a case report and review of the literature

Abstract Synovial sarcoma is an uncommon tumor of soft tissue, characterized by a specific SS18-SSX1/2/4 fusion gene. It is generally a lesion composed of monomorphic spindle cells, and can sometimes show variable epithelial differentiation. Here, we present the case of a young woman with a synovial sarcoma of the abdominal wall that showed an overwhelming (>90 %) epithelial glandular component mimicking adenocarcinoma, and only rare spindled areas. The diagnosis was confirmed by detection of targeted fusion transcripts associated with synovial sarcoma. We review the literature pertaining to synovial sarcoma, and we show that this case is only the sixth molecularly proven epithelial predominant synovial sarcoma in the literature. This report emphasizes the importance of molecular approaches in modern soft tissue pathology. Recognition of synovial sarcoma with predominant glandular component is imperative in order to avoid misdiagnosis of the tumor as metastatic adenocarcinoma, another type of sarcoma with epithelial differentiation, or a carcinoma with a sarcomatous component (sarcomatoid carcinoma), all of which have markedly different clinical management.