Subhepatic ciliated foregut cyst.

Foregut cyst derives from the primitive foregut and occurs in the tracheobronchial tree, mediastinum, liver, pancreas, tongue, and upper digestive tract. We report the first case of a foregut cyst in the subhepatic area. A computed tomographic scan of a 45-year-old man with dull backache showed a discrete subhepatic multiloculated cystic lesion. The cyst lining consisted of ciliated, columnar epithelium, goblet cells, and underlying double layer of smooth muscle. In addition to positivity for cytokeratin and epithelial membrane antigen in the epithelial cells, focal weak positivity for thyroid transcription factor was present, a novel finding further supporting respiratory differentiation. We hypothesized the occurrence of this cyst in this location based on the embryonic communication between the thoracic and abdominal cavities through the pericardio-peritoneal canal, eventually separated by pleuroperitoneal membranes. Abnormal buds off the tracheobronchial tree may get pinched off by these membranes, leading to migration into the abdomen.