High dorsal drainage routes of Spiegel's lobe.

BACKGROUND/PURPOSE: The venous drainage from Spiegel's lobe to the terminal portion of the hepatic veins has been described in the literature, but its morphology remains unclear.

METHODS

We examined 42 dissected liver specimens and 38 cast specimens.

RESULTS

In 8 of the 42 dissected liver specimens and 5 of the 38 cast specimens we found atypical but thick (over 3 mm) caudate veins that drained Spiegel's lobe and emptied into the terminal portion (along the most proximal 5-mm course) of the middle hepatic vein (MHV) or the inferior vena cava (IVC) near the MHV terminal (less than 10 mm from the MHV). We termed these the superior caudate vein. This vein ran upward between the caudate portal branches of the left and hilar bifurcation origins or through the territory of the left origin. The superior caudate vein, consistently coexisted with the typical vein(s). We also found several analogues of the superior caudate vein, such as the cranially shifted opening of the typical caudate vein and relatively thick proximal tributaries of the MHV from Spiegel's lobe.

CONCLUSIONS

Although the superior caudate vein, if present, seemed to have a large role in the venous drainage of the lobe, its incidence seemed to be too low for clinical relevance.