phrygian cap

Phrygian caps are the most common congenital anatomic variant of the gallbladder. It denotes folding of the fundus back upon the gallbladder body and is asymptomatic with no pathological significance.

Radiographic findings

A Phrygian cap may be identified on ultrasound, multiphase CT/MRI or cholescintigraphy .

Ultrasound 

May be wrongly interpreted as a septum in an otherwise normal gallbladder.

Multiphase CT/MRI

Usually clearly differentiate Phrygian caps from mass lesions.

Cholescintigraphy

When multiphase CT/MRI are inconclusive, cholescintigraphy may be critical in preventing an unnecessary cholecystectomy. Gallbladder appears often smaller than the gallbladder fossa. Delayed imaging demonstrates filling of the gallbladder ruling out an underlying mass lesion.

History and etymology

The appearance is reminiscent of a Phrygian cap a head garment worn by inhabitants of Phrygia (modern Turkey) 1200-700 BC . Of note, the smurfs also wear a similar hat.

Treatment and prognosis

As a benign anatomical variant, Phrygian caps should not be mistaken for a pathology and does not require treatment.

Differential diagnosis