Cholesterolosis is a part of the spectrum of degenerative and proliferative changes seen in the gall bladder, termed as hyperplastic cholecystosis, the other variant being adenomyosis. These changes are more commonly seen in the females, in the 4th and 5th decades and are usually asymptomatic. These changes are detected incidentally in 30-50% of cholecystectomy specimens.
Histologically, the normal gall bladder wall is comprised of a mucosa, lamina propria, muscle layer and connective tissue. Cholesterolosis results from abnormal deposits of cholesterol esters in macrophages within the lamina propria [foam cells] and in mucosal epithelium. The gall bladder may be affected in a patchy localized form or in a diffuse form. The diffuse form macroscopically appears as a bright red mucosa with yellow mottling [due to lipid], hence the term ‘strawberry gall bladder.’ In its localized form, cholesterolosis may present as multiple, very small polyps arising from the non-dependent wall, which may not be visualized radiologically. These polyps vary in size from 1-10 mm.
Ultrasound imaging of cholesterolosis is very definitive in its appearance. The polyps can be visualized as brightly echogenic non-mobile masses, with a ring down/ comet tail or reverberation artefact. These masses do not show shadowing, and there is usually no associated wall thickening.
This condition is not associated with an increased risk of malignancy and there is no known association with cholelithaisis and cholecystitis. Increased serum cholesterol level does not predispose to this condition. It is also not related to diabetes mellitus, atherosclerosis and hyperconcenteration of cholesterol in the bile.
|| Caption : Saggital sonogram of the gall bladder
Description : Saggital sonogram of the gall bladder shows multiple, echogenic, non-mobile foci without posterior shadowing, located in the wall.
If the polyps are small, the patient may simply be followed up; larger polyps need elective cholecystectomy, if symptomatic. The main concern is to rule out gallbladder malignancy.
Adenomyomatosis occurs as a part of same spectrum of degenerative changes as cholesterolosis and is radiologically similar to it. Therefore, sometimes it is difficult to distinguish between the two and the two conditions may often coexist. Adenomyomatosis occurs secondary to hyperplasia of mucosal and muscular elements, and shows Rokitansky-Aschoff sinuses, which are intramural diverticuli. These sinuses may contain cholesterol crystals, which give the reverberation artefact. There is usually associated gall bladder wall thickening.
CT scan may show a thickened GB wall, with the rosary sign in adenomyomatosis [enhancing mucosal epithelium with intramural diverticuli surrounded by non-enhancing hypertrophied muscle layer of gall bladder]. This sign mainly helps to distinguish adenomyomatosis from gall bladder malignancy. MRI aids in distinguishing cholesterolosis from adenomyomatosis. Nuclear scans [18-FDG] help in distinguishing small cholesterol polyps [no uptake] from gallbladder malignancy [which shows uptake].
1. Berk RN; van der Vegt JH; Lichtenstein JE. The hyperplastic cholecystoses: cholesterolosis and adenomyomatosis. Radiology 1983 Mar; 146(3)
2. Gore RM, Levine MS – Textbook of GI radiology. Philadelphia: Saunders; 1994:1709.
3. Cotrans S, Kumar V, Robins S. Robin's Pathologic Basis of Disease, 4th Edition. Philadelphia: Saunders; 1989: 973.
4. Kurtz A, Middleton W.: Ultrasound- The Requisites. St. Louis, MO: Mosby-Yearbook; 1996: 46-49.