Comparatıve Evaluatıon Of The Cytologıcal, Hıstopathologıcal And Immunohıstochemıcal Fındıngs Of Canıne Cutaneous And Subcutaneous Masses

Abstract

In this study, we compared the cytological, histopathological, and immunohistochemical diagnoses of 71 canine cutaneous and subcutaneous masses. Cytological diagnoses included 56 tumors (21 mesenchymal, 15 epithelial, 16 round cell, four melanocytic), 13 infl ammatory reactions, and two cysts. Of the 21 cytologically diagnosed mesenchymal tumors, three were later confi rmed non-tumoral (hematoma, granulation tissue, fi broepithelial polyp). Thirteen out of 15 epithelial tumors were correctly diagnosed cytologically, whereas two cases were confi rmed to be non-tumoral (fi broepithelial polyp, granulation tissue) after histopathological examination. One mast cell tumor was later confi rmed as fi brous hyperplasia; diagnoses were correct in other round cell tumors. Cytological diagnoses were correct for all melanocytic tumors and cystic lesions. Five cases which had been cytologically diagnosed as infl ammatory reactions were diagnosed as tumors (lymphoma, papilloma, sebaceous adenoma, and squamous cell carcinoma) after histopathological examination. Immunohistochemistry confi rmed the histopathological diagnoses of all epithelial and round cell tumors, while the diagnoses of six mesenchymal tumors were changed after the immunohistochemical examination. The total accuracy of cytology in the diagnosis of tumoral/non-tumoral masses was 84.5%, and the accuracy in the determination of benign/malignant behavior was 83%. Diagnostic accordance between histopathology and immunohistochemistry was 86.6%. High success rates obtained with cytological diagnoses prove that cytology is a reliable diagnostic tool. The main diagnostic challenge remains with mesenchymal tumors and tumors accompanied by infl ammatory reactions. The results suggest that immunohistochemistry is fundamental for diagnoses of most mesenchymal tumors.