Cyst of the falciform ligament of the liver: a rare cause of right upper quadrant pain.

Cysts of the falciform ligament are rare. Only a dozen cases have been reported in the English literature, with the first reported case in 1909. The etiology of these cysts is diverse but can be classified into primary and secondary causes. No specific complex exists and their presentations vary among persons. Physical examination may demonstrate a mass in the right upper abdomen. Although rare, they should be considered in the differential diagnosis of right upper quadrant abdominal pain. They are treated through excision.