Left flank pain as the sole manifestation of acute pancreatitis: a report of a case with an initial misdiagnosis.

Acute pancreatitis is not an uncommon disease in an emergency department (ED). It manifests as upper abdominal pain, sometimes with radiation of pain to the back and flank region. Isolated left flank pain being the sole manifestation of acute pancreatitis is very rare and not previously identified in the literature. In this report, we present a case of acute pancreatitis presenting solely with left flank pain. Having negative findings on an ultrasound initially, she was misdiagnosed as having possible "acute pyelonephritis or other renal diseases". A second radiographic evaluation with computed tomography showed pancreatitis in the tail with abnormal fluid collected extending to the left peri-renal space. We performed a literature review and discussed this rare occurrence of acute pancreatitis. We also discussed the clinical pitfalls in this case.