The solitary pulmonary nodule: a primer on differential diagnosis

Despite significant advances in noninvasive imaging techniques, management of the solitary pulmonary nodule (SPN) remains a challenge for chest physicians. Patients with SPNs are frequently asymptomatic, and the physical examination is seldom revealing. Accurate diagnosis is essential, because >50% of patients will require prompt disease-specific therapy. The complexity of the problem is best appreciated by reviewing the differential list, which includes nearly 80 distinct clinical entities. Consequently, a thorough understanding of the more common etiologies is necessary to adequately treat patients with SPNs.