Multiple Recurrence of Primary Orbital Synovial Sarcoma: Report of Two Cases and Literature Review

Synovial sarcoma (SS) is typically an aggressive malignant soft tissue tumor that mostly affects adolescents and young adults. It is extremely rare in orbit and carries a high risk of recurrence and metastasis, posing a challenge to ophthalmologists in diagnosing and managing. We present two primary orbital synovial sarcoma cases with unilateral exophthalmos and limited motility. Both male patients underwent reoperation in our hospital since tumor recurrence; the pathologic diagnoses were biphasic type and occult type, respectively. Both cases were posi-tive for EMA and CK, and SOX-9 and INI-1 were newly discovered immune markers. Fluorescence in situ hybridization analysis (FISH) revealed a translocation of t (X; 18) (p11.2; q11.2) that was detected in case 1 but not in case 2. Both patients initially refused adjuvant therapy, developed multiple recurrences and metas-tasis, and eventually died of distant metastasis. We provided clinical features, imaging findings, histopathology, treatments, outcomes of these very rare cases, and a literature review, underlining the timely diagnosis and management.