A 40-year-old man has had an increasing cough with hemoptysis for 2 weeks. He has never smoked and is in very good health. On physical examination, his temperature is 38.2deg C. A chest radiograph shows an area of consolidation in the right upper lobe. His condition improves with antibiotic therapy; however, the cough and hemoptysis persist for 2 more weeks. Chest CT scan now shows right upper lung atelectasis. Bronchoscopic examination shows a tan, circumscribed obstructive mass filling a right upper lobe bronchus. Which of the following neoplasms is most likely to produce these findings?

**Core Concept**
The patient's presentation with cough, hemoptysis, and a persistent obstructive mass in the right upper lobe bronchus suggests a bronchogenic neoplasm, specifically a type that arises from the mucous glands and leads to obstructive atelectasis.

**Why the Correct Answer is Right**
The patient's symptoms and findings are consistent with a mucoepidermoid carcinoma, a type of salivary gland-type tumor that can arise in the bronchi. Mucoepidermoid carcinomas are known to produce mucin, which can lead to obstructive atelectasis and hemoptysis. The tan, circumscribed obstructive mass seen on bronchoscopic examination is also consistent with this diagnosis.

**Why Each Wrong Option is Incorrect**
* **Option A:** Squamous cell carcinoma is a type of non-small cell lung cancer that typically presents with a central mass, but it is less likely to produce a mucoid obstructive mass.
* **Option B:** Adenocarcinoma is the most common type of lung cancer, but it typically presents as a peripheral mass and is less likely to produce a mucoid obstructive mass.
* **Option D:** Small cell carcinoma is a highly aggressive type of lung cancer that typically presents with widespread metastases and is less likely to produce a localized obstructive mass.

**Clinical Pearl / High-Yield Fact**
Mucoepidermoid carcinomas can be distinguished from other types of lung cancer by their production of mucin, which can lead to obstructive atelectasis and hemoptysis. This is an important clinical correlation to remember when evaluating patients with persistent cough and hemoptysis.

**Correct Answer:** C.

✓ Correct Answer: B. Carcinoid tumor