Evaluation of mediastinal mass

Mediastinal anatomy

The mediastinum is the thoracic space between the visceral pleura of the lungs. The boundaries of the mediastinum are the visceral pleura, thoracic inlet (spine, first ribs, and manubrium), diaphragm, sternum, and anterior spinal ligaments. The contents of the mediastinum include the heart, great vessels, trachea, esophagus, thymus gland, lymphatic tissue, and nerves.

The International Thymic Malignancy Interest Group (ITMIG) classification divides the mediastinum into prevascular, visceral, and paravertebral compartments (which roughly correlate to the historic anterior, middle, and posterior compartments, respectively).[1]Carter BW, Tomiyama N, Bhora FY, et al. A modern definition of mediastinal compartments. J Thorac Oncol. 2014 Sep;9(9 suppl 2):S97-101. https://jto.org/article/S1556-0864(15)33331-1/fulltext http://www.ncbi.nlm.nih.gov/pubmed/25396318?tool=bestpractice.com [2]Carter BW, Benveniste MF, Madan R, et al. ITMIG classification of mediastinal compartments and multidisciplinary approach to mediastinal masses. Radiographics. 2017 Mar-Apr;37(2):413-36. https://pubs.rsna.org/doi/10.1148/rg.2017160095 http://www.ncbi.nlm.nih.gov/pubmed/28129068?tool=bestpractice.com

[Figure caption and citation for the preceding image starts]: Anatomic compartments of the mediastinum.From the collection of Dr Muniappan [Citation ends].

Mediastinal contents

Prevascular (anterior) mediastinal contents include:

• Thymus gland

• Mediastinal fat

• Lymph nodes

• Extracardiac aorta.

Visceral (middle) mediastinal contents include:

• Pericardium, heart, ascending and descending aorta, great vessels

• Trachea and carina

• Lymph nodes

• Esophagus

• Vagus nerves

• Thoracic duct.

Paravertebral (posterior) mediastinal contents include:

• Proximal intercostal vessels

• Thoracic spinal ganglion

• Sympathetic nerve chain

• Lymph nodes.