American Board of Internal Medicine (ABIM) Certification Practice Exam

Which of the following is one of the most common anterior mediastinal masses?

1. Neurogenic tumors

2. Lymphoma

3. Malignant pleural mesothelioma

4. Fibromas

The correct answer is: Lymphoma

Lymphoma is identified as one of the most common anterior mediastinal masses due to its prevalence and the specific characteristics it exhibits when located in this area. The anterior mediastinum is the region of the chest between the sternum and the heart, and it is where a number of conditions can arise. Lymphoma, particularly thymic lymphoma or primary mediastinal B-cell lymphoma, typically manifests as a mass that can be identified via imaging studies such as chest X-rays or CT scans. Lymphoid tissues are abundant in the mediastinum, and lymphoma arises from these tissues, making it a frequent pathological finding in this anatomical space. Additionally, mediastinal lymphadenopathy can occur in various stages of the disease, further contributing to the mass effect and making lymphoma a common consideration during differential diagnoses for anterior mediastinal masses. The other options, while they may relate to the mediastinum to some extent, either occur more commonly in other locations or represent different pathological entities with lower prevalence in the anterior mediastinum specifically. Therefore, lymphoma’s connection to the lymphatic system and its typical presentation as a mass in the anterior mediastinum establishes it as the correct and most common answer in this context.