All of the following conditions are derived from the primitive embryonic foregut except:

D. Mesenteric cyst.

DISCUSSION: Mesenteric cysts are derived from lymphatic anlage in the abdomen and are unassociated with foregut development. The lung buds arise from the primitive foregut and anomalies associated with tracheopulmonary development are therefore all derived from foregut. These include tracheoesophageal fistula, congenital lobar emphysema, enteric cysts (which may communicate to the normal esophagus, lung, or spinal canal; e.g., neurenteric cyst), cystic adenomatoid malformations, solitary lung cysts, intra- and extralobar sequestrations, and bronchogenic cysts. The stomach and first part of the duodenum are also of foregut origin, and thus a gastric duplication is by definition derived from foregut.