Which of the following is a normal variant of the right lobe of the liver that might be mistaken for hepatomegaly?

Riedel's lobe is considered a normal anatomical variant of the right lobe of the liver, and it can extend more inferiorly than the typical liver shape, leading to an appearance that may suggest hepatomegaly or enlargement of the liver. Understanding this variant is important for proper imaging interpretation, as it may be mistaken for pathological liver enlargement.

Riedel's lobe is characterized by its elongated and downward projection, which distinguishes it from normal liver contour. This variant is usually asymptomatic and does not indicate any liver disease. Recognizing it is crucial in avoiding misdiagnosis that could lead to unnecessary interventions or further imaging.

In contrast, focal nodular hyperplasia and hepatic adenoma are both tumor-like conditions that may lead to an actual increase in liver size or mass lesions but do not represent normal liver anatomy. A liver cyst, while it can also be a benign condition, typically does not mimic the impression of hepatomegaly in the same anatomical manner as Riedel's lobe does. Therefore, Riedel's lobe stands out as the correct choice in the context of normal anatomical variations of the liver.