THE ANATOMIC complexity of the adult mediastinum leaves but little room for surprise at the possibilities of developmental aberrations that may occur therein.1 Prominent among such lesions are those cysts the structural elements of which point to the alimentary tract as their source. These abnormal structures are usually but not always2 discovered during childhood and are almost always entirely confined within the boundaries of the thorax.
The opportunity of having seen two examples of these pathologic curiosities which presented unusual features justifies this report.
3—K. O'N., a 2 year old white girl, was seen in March of 1949 because of a mass which presented in the left side of the neck when she strained, as in coughing. She had been subject to recurrent episodes of respiratory infections and respiratory distress since the age of 8 months. The breathing during such attacks was obstructive in type.