Benign Epithelial Tumors in Dog Skin

The document describes three types of benign epithelial tumors in dogs, known as epitheliomas: necrotising epitheliomas, intracutaneous keratinising epitheliomas, and trichoepitheliomas. Necrotising epitheliomas, observed in 37 cases (26 by the author), are common in terriers, occur in the subcutis, and do not metastasize. Intracutaneous keratinising epitheliomas, with 31 cases, extend from the cutis to the subcutis, often linked to the epidermis, and show no malignancy. Trichoepitheliomas, found in 17 cases, are located in the cutis and subcutis, resembling hair follicles but not forming true hairs, and are non-malignant. These tumors are typically found in dogs over 5 years old and are not observed on the head or limbs. The histogenesis suggests development from primitive hair matrix cells or epithelial proliferation in epidermal cysts.