“Lesioni nodulari di origine apocrina nel gatto Persiano: descrizione di 6 casi”

APOCRINE GLAND LESIONS IN THE PERSIAN CAT: 6 CASES The authors describe apocrine gland lesions in 6 Persian cats (1F and 5 M), ranging from 7 to 16 years, with a pinnal and facial distribution. The lesions were characterized by dark brown to black nodules, firm or slightly soft with alopecic surface. Cytological, histological and immunohistochemical investigations were performed. The cytology of a palpebral nodule showed a background of brownish material admixed with epithelial cells with vacuolated cytoplasm often containing pigmented, granular material and with rare macrophages. Histopathology showed multiple cysts, lined by well differentiated epithelial cells. The cysts contained homogeneous fluid material intermixed with brownish, granular material (apocrine cyst). Sometimes the epithelium was arranged in multiple layers, forming papillary projections towards the lumen (apocrine cystadenoma). Some epithelial cells were characterized by marked atipia, loss of the polarity and increased mitotic activity (apocrine adenocarcinoma). Immunoistochemistry (CK, SMA and Ki-67) confirmed the glandular origin and the proliferative nature of the lesions. In human medicine, a similar lesion characterized by multiple facial cysts, is described (apocrine hydrocystoma). Similar findings were rarely described in the dog and cat, where multiple cysts on the pinna (ceruminous cystomatosis) and apocrine gland tumors of the face (cystadenoma/apocrine carcinoma) are described. Summarizing, it is important to include cystic lesion of apocrine glands in the differential diagnoses of pigmented facial nodules of the cat.