A matched observational study of survival in cats with enucleation due to diffuse iris melanoma

Abstract

Although a small number of cases of feline diffuse iris melanoma have been documented to metastasize, the prognosis is not known. In this matched observational study, the survival time of 34 cats with enucleation due to histologically confirmed diffuse iris melanoma was recorded. These results are compared to the survival times of 83 age-matched control cats. Affected cats had enucleation between 2 and 10 years prior to the study. One group of control cats with eye disease had enucleation for either lymphoplasmacytic uveitis (27 cases), ocular trauma (seven cases), or endophthalmitis (four cases). In these control cats, enucleations were performed between 2 and 10 years prior to this study. Forty-five additional control cats presented for vaccination between 2 and 10 years prior to the study. The extent of diffuse iris melanoma at the time of enucleation in affected cats was graded according to the extent of involvement of ocular tissues and the invasiveness of the tumor. Affected cats have a significantly decreased survival compared with control cats and cats with extensive tumors at the time of enucleation have the lowest survival rates. Cats with tumors confined to the iris survive at the same rate as controls. These results suggests that early enucleation is important to avoid premature death, presumed to be due to cancer metastasis in cats with diffuse iris melanoma.

Use of high-resolution ultrasound as a diagnostic tool in veterinary ophthalmology

“…It has been reported that cats with diffuse iridal involvement have similar survival times as control groups, but that those tumors that involve other structures, such as the ciliary body, or have aggressive infiltration of the iris and its posterior epithelium are associated with increased mortality rates. 23 Prior to the development of HRUS and UBM,…”

Melanocytic Ophthalmic Neoplasms of the Domestic Veterinary Species: A Review

“…(22,24) Clinical histories suggest that FDIM begins as focal or multifocal areas of iridal pigmentation that gradually progress in size (Figure 4). (29,72,73) Lesions sampled at the earliest stage are diagnosed as iris melanosis, when pigmentation is strictly confined to the iris surface. The disease is designated as early FDIM when pigment cells extend into the iris stroma but the extent of involvement is still entirely within the iris.…”

A Comparative Review of Melanocytic Neoplasms

“…1,57,182 It typically presents as focal to diffuse iris hyperpigmentation rather than a discrete nodule or mass. 65,123 Glaucoma is a common sequela. 65 Melanoma originating in the limbus, conjunctiva, and nictitating membrane have also been reported, although they are very rare.…”