Interstitial Brachytherapy for Orbital Sebaceous Carcinoma

Sebaceous carcinoma is characterized by its aggressive local tumor behavior and ability to metastasize. Small periocular sebaceous carcinoma are typically treated by excision with cryotherapy. Larger tumors often require adjuvant external beam radiotherapy (EBRT) and/or exenteration surgery. When used alone, EBRT techniques typically exceed the tolerance of critical normal ocular structures. The interstitial orbital brachytherapy-boost technique permits dose escalation to the tumor bed, while minimizing radiation dose to critical normal ocular structures. Here, we present a case of orbital sebaceous carcinoma treated with excision, cryotherapy, and super-thick amniotic membrane fornix reconstruction. Then, after 3 weeks of healing, adjuvant-combined electron interstitial high-dose rate brachytherapy-boost was added to electron-beam radiotherapy to optimize the orbital radiation dose distribution, increase dose to inferonasal orbit, and allow relative sparing of orbital tissues. At 1-year follow-up, there was no evidence of orbital tumor, no significant eye lash loss, normal ocular motility, no radiation retinopathy, optic neuropathy and a visual acuity of 20/20.