Abstract
Primary lung carcinomas have been observed in 1 % of the dogs and 0.8 % of the cats necropsied. The primary lung carcinomas histologically resemble those of man. Age distribution is more or less the same in man and animals. The prevalence of the tumour types is however completely different. In domesticated animals the adenocarcinomas are dominating, while epidermoid carcinomas are rare. The anaplastic carcinomas include small cell and large cell types. These undifferentiated tumours are very rare in dogs. We have not seen any cases in the other domesticated species. Compared with the other types of bronchial carcinomas, the small cell as well as the large cell anaplastic carcinomas seem to occur at an earlier age, i.e. at 7 years. On the other hand, the bronchial adenocarcinomas have been observed in a higher age group (11¼ years in the dog and 13 years in the cat). A predilection towards lung tumours does not exist in the male sex. In spite of the low incidence, oncological investigations of spontaneous tumours in domestic animals may be important for research in the epidemiology and etiology of carcinoma in man.