Skin neoplasia in dogs and cats is a common finding in practice and can include sebaceous gland tumours such as adenocarcinoma and adenoma. This report describes a 10‐year‐old Cocker Spaniel presenting with a sebaceous gland neoplasia in the caudal left lung lobe, with no evidence of a primary tumour. To the authors' knowledge, sebaceous gland neoplasia has never been reported as a primary tumour in the lungs of a dog.