Asymptomatic true gallbladder duplication: a case report and review of the literature.

Gallbladder duplication is a rare event, with an incidence at autopsy of about 1/4000, with very few documented symptomatic cases reported. Preoperative diagnosis and differentiation of this malformation are important to prevent inadvertent damage to the biliary system, a complicated postoperative course, and repeat surgery. We present a case of true gallbladder duplication found incidentally during abdominal ultrasonography (US). The diagnosis was made with US and the Y-type duplication was demonstrated with magnetic resonance cholangiopancreatography (MRCP).