Left paraduodenal hernia (LPDH) is a retrocolic internal hernia of congenital origin that develops through the fossa of Landzert, and extends into the descending mesocolon and left portion of the transverse mesocolon. It carries significant overall risk of mortality, yet delay in diagnosis is not unusual due to subtle and elusive features. Familiarisation with the embryological and anatomical features of this rare hernia is essential for surgical management. This is especially important with respect to vascular anatomy as major mesenteric vessels form intimate relationships with the ventral rim and anterior portion of the hernia. As an illustrative case, we describe our experience with a striking example of LPDH, particularly focusing on the inherent diagnostic challenges and associated critical vascular anatomy. We advocate the role of diagnostic laparoscopy; however caution that decision to safely proceed with laparoscopic repair must occur only with confident identification of the vascular anatomy involved.