Infected urachal cyst initially misdiagnosed as an incarcerated umbilical hernia.

BACKGROUND Urachal abnormalities are a rare cause of lower abdominal pain. They are often initially mistaken for more common causes of lower abdominal pain, and the diagnosis is usually made during evaluation for one of these more common conditions. CASE REPORT We report a case of a painful periumbilical mass ultimately diagnosed as an infected urachal cyst. Although the cyst was evident sonographically, it was misidentified as an umbilical hernia, and the correct diagnosis was not made until the patient underwent computed tomography of the abdomen and pelvis before surgery. CONCLUSION Emergency physicians should consider urachal disease in patients presenting with lower abdominal pain and should also be familiar with both the clinical and radiologic findings characteristic of this disease.