1. Patients present with extrapulmonary signs of unknown origin and persistence, such as pestle and mortar fingers (toes), non-volatile pulmonary joint pain, male breast enlargement, dark skin or dermatomyositis, ataxia, phlebitis, etc. 2. 2. physical examination reveals vocal cord paralysis, superior vena cava obstruction syndrome, Horner’s sign, Pancoast’s syndrome, etc., suggesting the possibility of local invasion and metastasis. 3. Physical examination reveals hepatomegaly with nodules, subcutaneous nodules, and enlarged lymph nodes in the supraclavicular fossa, suggesting the possibility of distant metastasis.