The presence of central fat is pathognomonic of a benign pulmonary hamartoma. The presence of dense central or diffuse calcification is characteristic of a granuloma often from old fungal infection. Eccentric, stippled, or irregular calcium deposits are indeterminate in differentiating benign from malignant nodules. This allows direct comparison of the index nodule with a reference standard. CT scanning also allows for the radiographic examination of the mediastinum, liver, and adrenal glands to stage the patient for possible future surgical procedures.
Malignant nodules take up more tracer than normal tissue or granulomas.
This expensive new scan awaits the results of ongoing multicenter evaluations but may offer the ability to characterize the primary nodule and screen for regional and distant metastases. The primary goal in attempting to biopsy a SPN is to establish a benign diagnosis and spare the patient an invasive surgical procedure. However, in some instances a diagnosis of malignancy up front can be useful. Many patients are hesitant to undergo thoracic surgery without knowing they have a cancer. In other patients at moderate to high risk for surgical exploration, a positive preoperative biopsy may put to rest fears that a risky procedure may be unnecessary.