The purpose of this paper is the presentation and discussion of 2 unusual cases of cyst of the lung. The second case suggests a new cause of spontaneous pneumothorax in infants. Insofar as we have been able to determine, no similar case has been reported in modern literature. The attempted correlation of the embryologic, pathologic and clinical relationship was, to us at least, interesting.
We believe the cysts in these 2 cases arose from anlages of the primitive gut. At necropsy they were not seen to be in any way connected with the gastrointestinal tract. The cysts were not the usual small islands of aberrant intestinal or pancreatic tissue sometimes found along the esophagus but were definite hollow, spherical, organoid tissues, isolated at the periphery of the lung. Although they were almost identical in their gross and histologic pathologic aspects, they showed some decided differences in their clinical manifestations. The