Benign gallbladder and bile duct tumors are extremely rare. Which of the following statement(s) is/are true concerning benign biliary tumors?

a.Cholesterol polyps are due to foamy macrophages filled with cholesterol

b.Inflammatory polyps and cholesterol polyps are not considered to be premalignant

c.Gallbladder adenomas, like adenomas in other gastrointestinal organs, are considered premalignant

Benign gallbladder and bile duct tumors are extremely rare and can include pseudotumors or hyperplastic conditions which are thought to result from inflammatory states, or adenomas, which are most likely premalignant lesions. Cholesterolosis, or a strawberry gallbladder, is manifested by yellow spots visible on the surface of the gallbladder mucosa. This proliferation of foamy macrophages filled with cholesterol in the lamina propria may also result in the formation of polyps called cholesterol polyps. These polyps are thought to result from disturbance in cholesterol metabolism. Other pseudotumors of the gallbladder are inflammatory polyps which are composed of vascular connective tissue stalk with a single layer columnar epithelial cells and have a chronic inflammatory infiltrate. These lesions are not considered to be premalignant and are felt to be the result of chronic inflammation. Adenomas with hyperplasia of the epithelial layer of the gallbladder, like adenomas in other gastrointestinal organs can be sessile or papillary. Carcinoma in situ has been reported in these lesions, and they are thought to be premalignant. The cause of adenomas of the gallbladder is unknown; but most are not associated with the presence of gallstones. An adenomyoma of the gallbladder is a rare intramural mass or nodule. This lesion is characterized by a proliferation of the mucosal epithelium and hypertrophy of the mucosal layers of the gallbladder. Histologically in addition to muscular hypertrophy, invagination of the epithelial mucosa between muscle layers is evidenced. These lesions are also not considered premalignant.