SSX1 and synovial sarcoma: Morphologically, synovial sarcoma displays a monotonous spindle cell component, which is typically arranged in long fascicles or herringbone pattern, with varying degrees of epithelial differentiation.[1] Despite its histological diversity, synovial sarcoma is molecularly defined by a single alteration: the t(X;18)(p11.2;q11.2) translocation, involving the SS18 (formerly SYT) gene on chromosome 18 and 1 of several synovial sarcoma X (SSX) genes on chromosome X (usually SSX1 or SSX2).