GROSS EVALUATION, SAMPLING PROCEDURES AND HISTOLOGICAL CHARACTERIZATION OF FELINE MIDDLE EAR DISEASES

Introduction: Study of ear diseases is hampered by the difficult specimen preparation, resulting in the belief that these are uncommon in cats. The purpose of this study was to characterize gross and microscopic lesions of inflammatory and neoplastic origin, particularly of the middle ear. Materials and Methods: Ears from 26 cats were samplingduring necropsies, using a previously described technique (Sula et al. 2014) and were examined grossly and processed for routine histologic examination of the external, middle, and internal ear. Results: This sampling technique allows to have on a single slide the external, middle and internal ear andthis facilitates a single, complete and exhaustive evaluation of these structures. Gross and microscopic evaluation of feline ears highlighted numerous pathological conditions: 3 chronic external and medial otitis, 1 nasopharyngeal polyp, 1 ceruminous cystomatosis, 1 squamous cell carcinoma and 1 ceruminous adenocarcinoma with metastasis. Furthermore, we identified 1 case of mucoperiosteal exostoses. Conclusions: The sampling technique for the ear is simple to be performed and useful to evaluate all the anatomical structures. Focusing on middle ear alterations, these were frequently not reported in clinical history, but became evident during gross and, particularly, histopathological evaluations. We concluded that histologic evidence of middle ear diseases in cats is far greater than clinical literature reported; this suggests that ears, when possible, should be histologically evaluated. Furthermore, we reported for the first time mucoperiosteal exostoses in a domestic cat; this condition was described only in a single report in African lions.