Metastasis from systemic carcinoma to the eye occurs in 4-8 % of cases and the choroid is the most frequent site of ocular metastasis. The metastatic spread to the iris is uncommon and extremely rare. Iris metastasis can masquerade as iridocyclitis with pseudohypopyon or high intraocular pressure. In this paper history and management of metastasis to the iris in a case with colorectal carcinoma is presented.

A 55 year-old man with the history of colorectal carcinoma and multiple chemotherapy sessions since 3 years ago, was referred for newly diagnosed iris mass in right eye. On SLE there was a solitary yellow-white, fleshy vascularized amelanotic mass at infronasal part of iris. Otherwise ocular examination was normal in both eyes and IOP was 15mmHg. BCVA was 20/40 (plano) right eye and 20/80 (+5.00) left eye with history of amblyopia in left eye. UBM of right eye showed a 3mm*2.2mm iris mass with maximum thickness of 1.41mm. The lesion fulfilled the criteria of the metastasis. Last chemotherapy session was a year ago.

Treatment consisted of Ru-106 radiotherapy plaque which placed over lesion delivering 100 gray to the apex over 4 days. In last follow up visit two months after plaque radiotherapy, the iris lesion was in regression phase and no ocular complication related to radiotherapy was observed. BCVA was 20/40 same as before for right eye.

Plaque radiotherapy has been used for several decades to treat choroidal melanoma and more recently choroidal metastasis. This technique was also adapted to treat iris melanoma and have disclosed good safety and efficacy. In conclusion this approach could be used for cases of iris metastasis safely and results show regression of tumors in response. In our case the right eye was better eye by vision and the vision was saved by local plaque radiotherapy properly until now.