Document Type : Original Articles
Authors
1
Department of Clinical Sciences, Faculty of Veterinary Medicine, Ur.C., Islamic Azad University, Urmia, Iran.
2
Department of Pathology, Faculty of Veterinary Medicine, Ur.C., Islamic Azad University, Urmia, Iran.
10.22092/ari.2025.369826.3701
Abstract
Primary lung tumors are sporadic in dogs, and connective tissue-caused benign pulmonary adenomas and primary pulmonary neoplasms are infrequently reported in the genera Canis and Felis. This study aimed to examine the pathological and immunohistochemical features of canine pulmonary adenomas diagnosed over 10 years. The dogs with lung adenoma (n = 6) underwent necropsy and were investigated for hematological changes, histopathology (H&E, Masson's trichrome, and Perl's Prussian blue staining), and immunohistochemistry. Out of 882 dogs of various breeds with clinical respiratory signs, pulmonary adenomas were detected in six (0.68%), mostly large, 8-12-year-old dogs. Hematological assessments evidenced remarkable neutrophilia in the tumor-beading group (P< 0.05), and all tumors were identified as papillary adenomas. Interestingly, two tumor-affected dogs had concurrent chronic heart failure manifested in pulmonary hemosiderophages, which is being reported for the first time. The tumors' immunophenotype was TTF-1-, EGFR-, Napsin-A-, CEA-, EMA-, CK+, Vim-, p53-, and Ki67 negative for cell proliferation, indicating the lack of tumor malignancy potential. Whilst EGFR expression was not detected in tumorous lungs, the positive expression profiles were observed for EGFR, TTF-1, and Napsin-A in, respectively, around 30%, 30%-40%, and 40% of normal pulmonary cells. The expression profiles for these markers match in dogs’ normal pulmonary cells, with variations in TTF-1 and Napsin-A expressions acting as a potent source of EGFR mutation and its altered expression profile in malignant lung tumors such as adenocarcinomas. The results suggest that canine pulmonary adenomas are completely benign and have no malignant potential, and immunohistochemical assessments can aid in disease prognosis and inform the development of tailored therapy protocols.
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