Most pulmonary carcinoids are central obstructing masses involving a large to medium-sized bronchus. These neuroendocrine tumors have unpredictable behavior, but many are localized, resectable, and follow a benign course. They typically manifest with hemoptysis and the consequences of bronchial obstruction. In this case, the pneumonia in the right upper lobe probably resulted from obstruction to drainage caused by the tumor. Obstruction may lead to peripheral resorption atelectasis. Adenocarcinomas are common lung tumors, but are typically peripheral. A hamartoma is an uncommon but benign pulmonary lesion that also is located peripherally. Kaposi sarcoma can involve the lung in some patients with AIDS, and the tumor often has a bronchovascular distribution; obstruction is not common, but bleeding on biopsy is. Large-cell carcinomas are typically large, bulky, peripheral masses.