Solitary pulmonary nodule: New face on an old problem

Advances in radiologic techniques are improving the detection and evaluation of the solitary pulmonary nodule. While past chest films are valuable for identifying nodule growth, thin-section CT provides better assessment of calcification and can detect nodules not seen on chest films. Calcification in a central, laminated, or diffuse pattern indicates the nodule is benign. Risk factors for malignancy include nodule size greater than 2 cm; radiologic evidence of growth; and a history of smoking, airway obstruction, or malignancy. If the nodule is uncalcified and is 3 mm or smaller, repeat thin-section CT at 6 months; if it is 4 to 7 mm, repeat CT in 3 months. For nodules of 8 to 30 mm, consider contrast enhancement with CT, MRI, or positron emission tomography. If the nodule shows enhancement, biopsy or removal may be indicated.