Polysplenia syndrome: a review of the relationship with viscero-atrial situs and the spectrum of extra-cardiac anomalies

Polysplenia syndrome is classified as one of the situs ambiguous or heterotaxy syndromes and is classically termed left isomerism or bilateral left-sidedness. However, polysplenia is a controversial and complex entity with no fixed pathognomonic features but rather a broad spectrum of abnormalities. In many published case series, polysplenia was neither associated with viscero-atrial heterotaxy nor with duplication of left-sided structures. The relationship between polysplenia and viscero-atrial situs is not clear. Several recent case reports describe the association of polysplenia with situs inversus totalis or with pancreatic; venous and other anomalies or with several types of malignancy. This article provides the reader with a review of the literature as well as our own experience aiming at better understanding of the polysplenia syndrome, its relationship with viscero-atrial situs and the spectrum of associated extra-cardiac anomalies.