Etiology of Solitary Pulmonary Nodule Although cancer is usually the primary concern, solitary pulmonary nodules have many causes (see table Some Causes of a Solitary Pulmonary Nodule). Of these, the most common vary by age and risk factors, but typically include Granulomas Pneumonia Bronchogenic cysts Table Evaluation of Solitary Pulmonary Nodule The primary goal of evaluation is to detect cancer and active infection.