Successful Local Control of Orbital ASPS Using VMAT-Based Adjuvant Radiotherapy with Simultaneous Integrated Boost: A 3-Year Follow-Up Case Report

Orbital Alveolar Soft Part Sarcoma (ASPS) is an extremely rare malignancy, with limited case reports. Diagnosis is challenging owing to its slow-growing nature and non-specific symptoms. Furthermore, standardized treatment protocols are lacking, and the long-term outcomes remain poorly understood. We aimed to address these gaps by presenting a rare case of orbital ASPS and outlining the diagnostic challenges, treatment approach, and long-term follow-up to inform the clinical management. A 28-year-old male presented with diplopia, restricted ocular movements, and orbital swelling. Magnetic resonance imaging revealed a 3.81 × 1.99-cm mass adjacent to the left medial rectus muscle, which was histopathologically confirmed as ASPS. A personalized therapeutic approach involving surgery and radiotherapy achieved stable disease, preserved vision, and no recurrence over a 3-year follow-up period. These findings contribute to the existing body of knowledge regarding the clinical management of orbital ASPS, underscoring the importance of individualized treatment strategies. Routine long-term surveillance and multidisciplinary care are essential in the management of rare cases. This case further emphasizes the need for continued research and documentation to enhance the diagnostic accuracy and refine the treatment guidelines for ASPS.