Iridociliary cysts masquerading as neoplasia in cats
Fonte: Jessica A. Fragola, Richard R. Dubielzig, Ellison Bentley and Leandro B. C. Teixeira
Sagittal section of theformalin-ﬁxed globe showing a large, thick-walledpigmented cyst (asterisk) displacing the iris(arrows) anteriorly
To report 14 neoplasia-free feline eyes enucleated for suspected intraocularneoplasia containing only iridociliary cysts. To analyze clinical ﬁndings that may have led veterinarians to suspect neoplasia in these globes.Procedures The archives at the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) were searched to identify neoplasia-free feline globes enucleated for suspected neoplasia. Clinical data were obtained from medical records, veterinarian surveys, and COPLOW submission forms. All samples were examined grossly and histologically.Results All eyes were free of neoplasia and contained one or more iridociliary cysts.Nine of 14 globes were enucleated by or based on the recommendation of a board-certiﬁed veterinary ophthalmologist. In eight of 14 cases, the submitting clinician listed melanoma as the only suspected diagnosis; in six of 14 cases, ‘tumor’ or ‘mass’was listed. Clinical examination revealed a darkly pigmented intraocular mass in 11 of 14 cases. The mass was clinically perceived to be within the iris in seven of 14 cases.When examined histologically, 11 of 14 eyes contained multiple cysts, 13 of 14 contained multiloculated cysts, eight of 14 had a hyperplastic iris pigmented epithelial tumor cysts with thick black walls, and ﬁve of 14 had cysts prolapsed into the anterior chamber.Conclusions Although most iridociliary cysts in cats are easily diagnosed on clinical examination, a subset may be mistaken for neoplasia. In cases of suspected iris melanoma, iridociliary cysts should be considered as a differential diagnosis, especially if amass appears to emanate from behind the iris, dyscoria is present, or if similar changes are noted in the contralateral eye.