Significant clinical, functional and radiological response with sirolimus in refractory complex orbital venolymphatic...

Orbital venolymphatic malformations (OVLM) are rare congenital vascular anomalies that may cause progressive proptosis, visual loss, facial disfigurement and marked psychosocial burden. Management is challenging especially when the disease is multifocal, diffuse and with limited response to conventional therapies. We describe a school-aged child with a right eye refractory extensive orbital venolymphatic malformation leading to marked visual impairment and disfigurement despite multiple prior sclerotherapy sessions. After multidisciplinary evaluation, oral sirolimus was initiated with written informed consent from the parents in a refractory setting. After 9 months of treatment, visual acuity improved from counting fingers at 3 metres to 6/12, proptosis reduced substantially, conjunctival chemosis resolved completely, ocular motility became full with minimal residual hypotropia and the palatal lesion resolved, with mild residual lip hypertrophy. At 19 months of follow-up after initiation of therapy, visual acuity had further improved to 6/9-2, MRI demonstrated near-complete radiological regression of the lesion, no clinically significant adverse effects or recurrence. The child resumed normal activities. This case highlights the potential role of systemic mechanistic target of rapamycin (mTOR) inhibition in complex, refractory orbital venolymphatic malformations and highlights careful patient selection and long-term follow-up.