General Considerations

•benign epithelial proliferation arising from superficial epithelium between hair follicles

•small to moderate size with pore containing keratin ± hair follicles

•rupture produces a severe pyogranulomatous dermatitis due to the keratin contents of the cyst

•cytology: keratinous debris, clusters of squamous cells ± cholesterol crystals

•1 case reported in the cat

•intracutaneous cornifying epithelioma is common in dogs

•sex predisposition: males

•2 distinct clinical patterns for intracutaneous cornifying epithelioma: solitary and generalized

Solitary Intracutaneous Cornifying Epithelioma

•solitary form is more common in purebred dogs along the back, neck, thorax, and shoulders

•treatment: surgery

•prognosis: good

Generalized Intracutaneous Cornifying Epithelioma

•Norwegian Elkhound and Keeshond are predisposed to the generalized or multicentric form

•treatment: cryosurgery or retinoids (etretinate is better than isotretinoin)

•prognosis: guarded to good with 71% complete response and 29% to retinoids, but recurrence is common following cessation of treatment