Persistent mass after treatment for orbital rhabdomyosarcoma

Rhabdomyosarcoma was once a disease with a very poor outcome, but advances in imaging, chemotherapy, and radiation therapy have improved the prognosis of these patients. What was once a surgical disease treated with morbid resection is now predominantly a medical disease diagnosed with biopsy and treated with chemotherapy and radiation. However, such patients may have a residual mass after completing treatment. This situation presents a challenge, as it may not be clear whether the persistent mass is active tumor or treated tumor. This report describes the presentation and management of such a case in the orbit and demonstrates that a residual orbital mass may remain and represent completely treated tumor.