Alveolar adenoma: an unusual lung tumor.

A 34-year-old woman presented with chest pain and a solitary pulmonary nodule on chest roentgenogram. She was diagnosed with a rare benign lung tumor, alveolar adenoma of the lung, through pathological examination of the surgical specimen resected from the left upper lobe. Clinicians should also keep this entity in mind when making the differential diagnosis of a solitary pulmonary nodule.