Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal (GI) tract. They constitute a distinct group of mesenchymal tumors, presenting different histological aspects in comparison to other types, such as tumors of neural origin (schwannoma and paraganglioma), smooth muscle cell origin (leiomyoma and leiomyosarcoma), fibroblastic tumors, and vascular tumors (angiosarcoma), among others. Gastrointestinal autonomic nerve tumors (GANTs) are rare tumors, probably developing from the myenteric plexus of Auerbach. They are considered as a subgroup of GISTs with specific ultrastructural appearance. Although cytological, immunohistochemical, and ultrastructural characteristics of GIST and GANT appear to be relatively heterogeneous, similarities in pathology may complicate the diagnosis (1).

HighlightsAccessory right hepatic duct, that merged to the common bile duct.The accessory right hepatic duct drains the posterior segments of the right hepatic lobe.A detailed mapping of the bile tree is essential especially before major procedures.