A mesenchymal hamartoma in the dorsomedial eyelid of a Staffordshire bull terrier and the incidence and histological features of twenty-two canine mesenchymal periocular hamartoma cases are reported. The archives of the “Comparative Ocular Pathology Laboratory” of Wisconsin (USA) were searched for canine mesenchymal periocular hamartoma. Signalment, clinical appearance, location and histological findings are summarized for twenty-two dogs, containing fourteen different breeds, between four and fourteen years old. Fifteen hamartomas were located at the lateral canthus. Histologically, they consisted of fully differentiated fibrous tissue interspersed with adipose tissue, with bundles of skeletal/smooth muscle in ten cases, and peripheral nerve tissue in two cases. No mitotic figures were noted. Mesenchymal hamartomas may present as a subcutaneous, subconjunctival or orbital mass. Although they have a predisposition to occur at the lateral canthus, they may be located elsewhere on the eyelids or in the orbit.

An 8-year-old Scottish terrier was presented with a red and painful right eye. Slitlamp biomicroscopy and ocular ultrasound demonstrated the presence of a large mass in the anterior chamber. Enucleation was performed one week after initial presentation. Histological examination of the eye revealed a relatively well-delineated mass distorting the dorsal iris and occupying most of the anterior chamber. The tumor was composed of fully differentiated adipose tissue and normal hematopoietic cells of the three major blood-forming elements. These findings were most consistent with the diagnosis of an anterior chamber myelolipoma distorting the iris. To the author's knowledge, this is the first report of an intraocular myelolipoma in any species.

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Corneal sequestra are ophthalmic lesions that are remarkably common in Persian, Himalayan and exotic cats. In this study, the genetic aspects of this disease were investigated in a population of cats originating from a single cattery. Odds ratios were calculated for parents with affected offspring. The heritability of (owner-reported) corneal sequestra was estimated with a Markov chain Monte Carlo procedure. Well-phenotyped cases and controls were used for a genome-wide association study. Data from 692 cats originating from the cattery, of which 61 were affected, were used. Cats from two specific mothers had significantly higher odds of developing corneal sequestra, but no significant effect of the fathers was found (after correction for the mothers). The heritability of corneal sequestra was estimated to be 0.96. A genome-wide association study with 14 cases and 10 controls did not reveal an associated chromosomal region. The large effect that genetic factors had on the development of corneal sequestra in this study suggests that selective breeding could be an effective way to reduce the prevalence of this condition in these cat breeds.