A 12-year-old poodle dog was presented with a history of severe dyspnea. Radiology revealed diffuse pulmonary lesion which was diagnosed as interstitial pneumonia. At necropsy there were multiple small coalescent nodules distributed throughout the lung parenchyma. Histologically the nodules consisted of cubic to low columnar atypical epithelial cells which were PAS-negatives. In the immunohistochemistry reaction this cells were marked for cytokeratin, TTF (thyroid transcription factor)-1 and surfactant apoprotein A (SP-A). The neoplastic cells were negative for vimentin and cromagranine A. The necrotic areas were not marked for TTF-1 and SP-A. Based of the histopathological and immunohistochemistry findings a diagnosis of non-mucinous bronchioloalveolar carcinoma with diffuse involvement of the lung was made. This is a rare form of presentation for this tumor, and it can mimetize pneumonia on clinical and morphological examination. A definitive diagnosis for this condition should be based on histopathology and immunohistochemistry.
immunohistochemistry; neoplasm; lung; cancer; pathology
