Non-neoplastic lesions of equine skin in the central United States and Canada: a retrospective study.

A retrospective study evaluated the clinical data and histologic features of non-neoplastic dermatologic lesions in skin biopsies from horses, donkeys, and mules submitted over a 10-year period to the Colorado State University Diagnostic Medicine Center and to the University of Saskatchewan Western College of Veterinary Medicine and Prairie Diagnostic Services. A total of 1793 non-neoplastic biopsies were available for analysis. Based on the histologic description and morphologic diagnosis, each submission was classified as inflammatory, or non-neoplastic/non-inflammatory. Results of this study demonstrate that non-neoplastic equine cutaneous biopsies are predominantly inflammatory, but histopathology alone may not be sufficient to definitively identify the underlying etiologies driving inflammatory lesions. Clinical correlation, including breed, age, and distribution of the cutaneous lesion, as well as ancillary tests such as bacterial or fungal culture are required to complete the clinical picture and arrive at the appropriate clinical diagnosis.