**Question:** A 25-year-old is seen in the clinic for assessment of an incidental finding on a CXR of a 2-cm solitary pulmonary nodule in the left lower lobe. He feels well and reports no dyspnea, chest pain, or constitutional symptoms. He does not smoke and has never had a previous CXR. The physical examination is completely normal. The nodule has a "popcorn ball"-type calcification pattern. Which of the following is the most appropriate next step in management?

A. Perform a CT scan to evaluate the nature of the nodule
B. Perform a biopsy of the nodule
C. Follow-up CXR in 3 months
D. Perform a bronchoscopy for diagnostic purposes

**Correct Answer:** A. Perform a CT scan to evaluate the nature of the nodule

**Core Concept:** A solitary pulmonary nodule (SPN) is an abnormal pulmonary opacity on a chest radiograph, usually less than 3 cm in diameter. The "popcorn ball"-type calcification pattern refers to the presence of small, coarse, and evenly distributed calcifications within the nodule. These calcifications are characteristic of benign lesions such as hamartomas, cysts, or granulomas.

**Why the Correct Answer is Right:** Given the small size, benign appearance, and clinical stability of the patient, it is crucial to further evaluate the nature of the nodule to rule out malignancy. A computed tomography (CT) scan is the most appropriate next step as it provides detailed information about the nodule's size, location, shape, and margin, which are important factors to differentiate between benign and malignant lesions.

**Why Other Options are Incorrect:**

A. Performing a biopsy would be inappropriate in this case as it carries a risk of bleeding, infection, and pneumothorax. Additionally, a biopsy may not accurately represent the entire nodule and may miss the malignant component.

B. A biopsy is not necessary for a stable, small, and benign-appearing nodule, as the "popcorn ball" calcification pattern supports the benign nature of the nodule.

C. A follow-up chest X-ray in 3 months could lead to misdiagnosis, especially considering the appearance of the nodule, as chest X-rays are less sensitive than CT scans in detecting nodule characteristics.

D. A bronchoscopy is not required as the patient is clinically stable and the nodule has a benign appearance. A bronchoscopy is primarily used for evaluating airway lesions or evaluating suspected lung cancer patients with respiratory symptoms.

**Clinical Pearls:**

1. In the context of a small, benign-appearing nodule with the "popcorn ball" calcification pattern, CT scan is more sensitive and specific than chest X-ray for nodule evaluation.
2. Clinical stability and benign-appearing nodules generally do not require invasive procedures like biopsy or bronchoscopy.
3. Regular follow-up chest X-rays may lead to misdiagnosis as they are less sensitive than CT scans.

4. Biopsy is not necessary in stable patients with benign-appearing nodules, as the appearance