https://www.vetsurgeon.org/f/clinical-questions/27869/could-this-be-a-tumour-or-innocent-pigmentation Rescue cat , approximately 3 years old. Not tested for FeLV/FIV. Owner has noticed an increase in pigmentation in one eye in the last few weeks. Normal PLR and menace in both eyes. Retinas appear normal. The affected iris does not appear thickened anden-USTelligent Community 10https://www.vetsurgeon.org/thread/207704?ContentTypeID=1Sun, 03 Feb 2019 23:15:20 GMT146601cc-3922-4be7-9974-7e1d4e45a66b:51b7c376-218f-4549-935a-b2bd4f31e898KathW<p>Thanks for a very helpful and comprehensive reply Robert. It will help me to discuss the possible outcomes and reasons for a full assessment with the owner.</p><div style="clear:both;"></div>https://www.vetsurgeon.org/thread/207701?ContentTypeID=1Sun, 03 Feb 2019 22:12:32 GMT146601cc-3922-4be7-9974-7e1d4e45a66b:791947af-bcb6-48de-a915-9008afcf1f53Robert Lowe<p>At this stage it is probably just a benign melanosis but ideally slit lamp examination should be performed to check for free floating pigment cells in the anterior chamber and any variation in iris architecture. A benign iris melanosis may still transform at any point so regular reviews are a good idea. The good news is that even if it is a melanoma the average time from enucleation to death is at least 3 years and that enucleation at the right time may be curative. The other eye may also develop melanosis so I wouldn&rsquo;t enucleate prophylactically unless high suspicion of transformation.&nbsp;</p><div style="clear:both;"></div>