A pulmonary hamartoma is a benign tumor found in the lungs, typically composed of a mixture of different types of tissues, such as cartilage, fat, and connective tissue. These tumors are usually small and asymptomatic, meaning they often do not cause any noticeable symptoms. They are most commonly discovered incidentally during imaging tests, such as a chest X-ray or CT scan, performed for other reasons. Although pulmonary hamartomas are non-cancerous, they can sometimes be mistaken for malignant tumors. The exact cause of these growths is not well understood, but they are generally considered to be developmental abnormalities. Treatment is usually not necessary unless the hamartoma causes symptoms or grows significantly, in which case surgical removal may be recommended.