Chapter 28

### Key Points

1. Robotic surgery offers advantages for the resection of selected solid mediastinal chest masses.

2. A calcified mass in the posterior mediastinum is most commonly of neural cell origin.

3. Neuroblastomas that arise in the mediastinum usually have a more favorable prognosis than those in other locations.

4. A careful and thorough evaluation for potential airway obstruction is required prior to biopsy for patients with a large anterior mediastinal mass. Alternative sites of biopsy should be investigated if general anesthesia is of considerable risk.

5. A calcified mass located within the anterior mediastinum is typically a teratoma.

6. Complete surgical resection is the goal for mediastinal germ cell tumors.

7. Mediastinal hemangiomas are rare causes of respiratory distress or feeding difficulties in infants. Propranolol may help shrink these lesions, but it has not been prospectively studied.

8. Lymphatic malformations (cystic hygromas) are benign lesions that may envelop vital structures. Interventional radiology techniques offer highly effective treatment of macrocystic mediastinal lesions.

9. The role of thymectomy for myasthenia gravis (MG) is controversial, and there is a lack of prospective studies documenting efficacy.

### Anatomy

The mediastinum is the portion of the thoracic cavity that lies between the 2 pleural sacs. It is bounded superiorly by the thoracic inlet, inferiorly by the diaphragm, anteriorly by the sternum, and posteriorly by the vertebral bodies and costovertebral sulci. Classic anatomic definitions of the mediastinum in adults may fail to convey a clear, precise understanding of the surgical anatomy in childhood. In the pediatric population, it is preferable to divide the mediastinum into 3, rather than 4, compartments. The anterior mediastinum is defined as the area between the sternum and the pericardial sac including the cephalad portion of the mediastinum. The middle mediastinum remains bounded by the anterior and posterior surfaces of the pericardium. The posterior mediastinum encompasses the area from the posterior aspect of the pericardium to the vertebral bodies and their costovertebral sulci, including the cephalad portion of the mediastinum.

These definitions provide clinicians with descriptive terminology that is more consistent with the surgical anatomy in the pediatric age group. For instance, a neurogenic tumor arising from the third sympathetic ganglion should be considered a superior mediastinal mass, but in order to formulate an accurate differential diagnosis, the posterior position of the lesion is the most important information to be imparted. The visceral contents of these 3 redefined mediastinal compartments are listed in Table 28-1.

Table 28-1Visceral Contents of the Mediastinal Compartments as Redefined for the Pediatric Population

### Introduction

Mediastinal masses are not common ...

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.

Ok

## Subscription Options

### AccessSurgery Full Site: One-Year Subscription

Connect to the full suite of AccessSurgery content and resources including more than 160 instructional videos, 16,000+ high-quality images, interactive board review, 20+ textbooks, and more.