Gallbladder mucocele caused by intestinal metaplasia in lithiasic cholecystitis: A case report and literature review of a rare association

Abstract

Introduction: Mucin hypersecretion promoted by intestinal metaplasia can lead to gallstone formation. The presence of large amounts of mucin induced by a change in biliary epithelium structure is called a mucocele, a usually benign condition studied among animals but rarely described in humans. This entity must be distinguished from hydrops, a condition secondary to an impacted gallstone in the cystic duct leading to an outlet obstruction and distension of the gallbladder.

Presentation of case: We report a case of a 51-year-old female with lithiasic cholecystitis showing areas of intestinal metaplasia associated with a mucocele. Laparoscopic cholecystectomy was performed with an uneventful postoperative course. Macroscopic findings revealed a dilated gallbladder filled with mucoid fluid. Signs of chronic and focally acute cholecystitis with areas of intestinal metaplasia were observed microscopically.

Discussion: Lithiasic gallbladders can bear a gene that is found in goblet cells of intestinal metaplasia, leading to mucin hypersecretion. Metaplasia - a benign lesion often encountered on cholecystectomy specimens - can be the precursor of carcinoma. Mucin-producing gallbladder carcinoma is a very aggressive tumor that can appear as a mucocele. Consequently, preoperative computed tomography or magnetic resonance cholangiopancreatography should be performed in the presence of an unusual aspect on sonography.

Conclusion: Metaplastic changes in gallbladder epithelium associated with an overproduction of mucin and lithiasic cholecystitis reported in this case is a rarity. Malignancy is an alternative diagnosis of gallbladder mucocele that must be suspected whenever preoperative imaging of the gallbladder is atypical.

Keywords: Carcinoma; Case report; Cholecystitis; Gallbladder mucocele; Intestinal metaplasia; Literature review.

Fig. 1

Preoperative sonography. (A) Lithiasic cholecystitis with a stone of 26 mm (red arrow). (B) Sludge (yellow arrow), thickening of the gallbladder of 4.6 mm (red arrowhead).

Fig. 2

Macroscopic illustration of the gallbladder. Mucus is displayed on the left, and a transversal section of the cystic duct is shown on the right (red arrow) with adherent mucus (yellow arrow).

Fig. 3

Microscopic sections showing the intraluminal mucus. (A), (B) Mucus (red arrow) adheres to the normal biliary epithelium. Alcian blue-Periodic acid-Schiff (AB-PAS), magnification x 40 and × 200. (C) Intraluminal mucus, magnification x 40.

Fig. 4

Microscopic illustration of the gallbladder. A Rokitansky-Aschoff sinus (red asterisk) contains a stone fragment (red arrow) and mucus (yellow arrow). The normal biliary epithelium is marked with the yellow asterisk. Haematoxylin and eosin, magnification x 40.

Fig. 5

Microscopic illustration of the gallbladder. (A) Intestinal metaplasia (red arrow) without dysplasia. Normal biliary epithelium (yellow arrow). Haematoxylin and eosin, magnification x 40. (B) The same section at magnification x 200. A single layer of columnar cells with basally located nuclei is seen in the normal biliary epithelium. Intestinal metaplasia is characterized by the presence of goblet cells, usually found in the small intestine epithelium.