A rare cause of vomiting: annular pancreas.

Annular pancreas is a rare congenital anomaly that consists of a ring of pancreatic tissue partially or completely encircling the second part of the duodenum. It can affect anyone from neonates to adults, and is difficult to diagnose because it can present in a wide range of clinical conditions. Although cases have also been reported in adults, symptomatic cases are often referred in infancy or early childhood. A 17-year-old female patient who was diagnosed as having annular pancreas is reported. The patient had had non-bilious vomiting accompanied by abdominal pain, especially 5-10 minutes after meals, for seven years. Annular pancreas, which may be seen at any age, should be considered in the differential diagnosis of patients with non-bilious vomiting, particularly after meals, over a long period.