Annular pancreas. Etiology, classification and diagnostic imaging

Area of Science:

• Gastroenterology and Hepatology
• Embryology and Developmental Biology

Background:

• Annular pancreas is a rare congenital anomaly resulting from abnormal pancreatic duct fusion during embryonic development.
• It is characterized by pancreatic tissue encircling the duodenum, potentially causing obstruction.
• Classification includes Type I (divisional), Type II (branch), and Type III (main duct) annular pancreas based on duct fusion patterns.

Observation:

• This study focuses on a rare variant where the tail of the annular duct fuses with the dorsal pancreatic duct, forming the main duct.
• Diagnostic imaging modalities such as endoscopic retrograde cholangiopancreatography (ERCP), hypotonic duodenography, computed tomography (CT), and ultrasound were utilized.
• Each imaging technique provides distinct views of the annular pancreas anatomy.

Findings:

• The described variant involves a specific fusion pattern of ventral and dorsal pancreatic ducts.
• Imaging findings from ERCP, hypotonic duodenography, CT, and ultrasound are presented.
• The study highlights the characteristic appearances of this rare annular pancreas subtype across different modalities.

Implications:

• Accurate diagnosis of annular pancreas subtypes is crucial for appropriate clinical management.
• Understanding the embryological basis aids in recognizing this anomaly.
• Combined use of ERCP or hypotonic duodenography with CT or ultrasound is recommended for definitive diagnosis.