Subhepatic ciliated foregut cyst

Area of Science:

• Gastroenterology and Hepatology
• Developmental Biology
• Surgical Pathology

Background:

• Foregut cysts typically originate from the primitive foregut and are found in various locations, including the respiratory tract, mediastinum, liver, pancreas, and upper digestive system.
• The subhepatic area, located beneath the liver, is an unusual site for foregut cyst development.

Observation:

• A computed tomographic (CT) scan revealed a multiloculated cystic lesion in the subhepatic region of a 45-year-old male presenting with backache.
• Histopathological examination of the cyst lining showed ciliated columnar epithelium, goblet cells, and a double layer of smooth muscle.
• Immunohistochemical analysis demonstrated positivity for cytokeratin and epithelial membrane antigen, with focal weak positivity for thyroid transcription factor, indicating respiratory differentiation.

Findings:

• This case represents the first reported instance of a foregut cyst in the subhepatic location.
• The histological and immunohistochemical findings strongly support a respiratory epithelial origin for the cyst.
• The presence of thyroid transcription factor further supports the hypothesis of respiratory differentiation.

Implications:

• The findings suggest that foregut cysts can develop in the subhepatic area, potentially arising from aberrant embryonic development.
• The proposed mechanism involves abnormal budding from the tracheobronchial tree during embryonic development, with subsequent migration into the abdomen via the embryonic pericardio-peritoneal canal.
• This case expands the known anatomical distribution of foregut cysts and provides insight into their embryological origins.