Linear organoid nevus in a dog

A skin lesion classified as linear organoid nevus is reported in a female s tandard Schnauzer. The dog was brought to the clinic with multiple hyperpig mented, hyperkeratotic linear or ovoid plaques on the head, neck, trunk, ea rs, and limbs. Histological findings included severe orthokeratotic hyperke ratosis, focal parakeratosis and hyperplasia of both the epidermis and the follicular infundibular epithelium, and marked sebaceous hyperplasia. No im provement was noted with systemic retinoid therapy. This is the second line ar organoid nevus described in a dog, and the first report of retinoid ther apy for this disease.