American Board of Internal Medicine (ABIM) Certification Practice Exam

What imaging characteristic is typical of small cell lung cancer?

1. Diffuse pulmonary nodules

2. Large hilar mass with bulky mediastinal lymphadenopathy

3. Patchy infiltrates

4. Pleural effusion

The correct answer is: Large hilar mass with bulky mediastinal lymphadenopathy

Small cell lung cancer (SCLC) is typically characterized by a large hilar mass along with bulky mediastinal lymphadenopathy. This is due to the tendency of this type of cancer to metastasize early and spread to regional lymph nodes, leading to prominent masses in the central thoracic region. In imaging studies, particularly chest CT scans, the appearance of these large mass lesions along with associated lymphadenopathy is a distinguishing feature of SCLC. SCLC is classified as a neuroendocrine tumor and usually presents at a more advanced stage, which contributes to the large size of the tumors and the extensive lymph node involvement. The presence of a significant mediastinal component is an important finding when diagnosing this cancer. In contrast, other imaging characteristics found in lung cancer types such as non-small cell lung cancer may present with diffuse pulmonary nodules, patchy infiltrates, or pleural effusions, but the distinctive presentation of a bulky mediastinal mass is primarily associated with small cell lung cancer. Therefore, recognizing the imaging characteristic associated with SCLC is crucial for making an accurate diagnosis and determining appropriate treatment strategies.