A lymphomatoid granulomatosis of the lungs in young dogs.

Clinical signs in three young dogs with primary lung neoplasms included cough, weight loss and anorexia. Chest radiographs taken in the terminal stages of the disease showed nodular and diffuse consolidation of the lungs typical of primary neoplasms. Macroscopically the lungs were infiltrated by firm, pale tissue; similar tissue replaced the enlarged bronchial lymph nodes. In two dogs similar deposits were found also in the liver and spleen. The infiltrates were composed of atypical, polymorphous lymphoreticular cells. Invasion of pulmonary blood vessels and of bronchi and bronchioles was striking. The lesions closely resembled those of lymphomatoid granulomatosis, a rare human disease of unknown cause.