Airways Disease

Pulmonary hamartoma is a benign neoplasm of the lung. It accounts for the majority of benign lung tumors. A hamartoma is composed of a variety of mesenchymal elements that may include cartilage, calcification, fat, epithelial cells, and smooth muscle. While benign, they are considered true neoplasms, and may demonstrate slow growth. Hamartomas are most commonly discovered in the 6th decade of life. Men have a 2-to-3 fold increased incidence compared to women. Most hamartomas are discovered incidentally. However, patients may rarely present with symptoms such as cough, hemoptysis, or recurrent pneumonia due to lesion proximity to the airway. On CT, hamartoma classically manifests as a small pulmonary nodule with intrinsic chondroid calcification and fat. These findings are essentially diagnostic of hamartoma. However, only 60% of hamartomas contain macroscopic fat, and even fewer (15%) exhibit characteristic “popcorn” calcification. Most hamartomas do not require resection, unless they are symptomatic. Other benign lesions also occur in the lung, but are much less common. A chondroma differs from a hamartoma in that is entirely comprised of cartilage. Chondromas are a component of Carney triad, which is also comprised of gastric leiomyosarcomas and extraadrenal paragangliomas. Lipomas and leiomyomas are other rare benign neoplasms, composed of fat and smooth muscle, respectively. Benign neurogenic neoplasms may also occur within the central airways.