Uncommon Presentation of Xanthogranulomatous Cholecystitis in a True Gallbladder Diverticulum: A Case Report and Literature Review

Introduction

The gallbladder develops during the fourth week of gestation from the hepatic diverticulum, which also gives rise to the liver, extrahepatic biliary ducts, and ventral part of the pancreas [1]. Infrequently, gallbladder malformation or disruption in embryogenesis leads to congenital anomalies. There are various congenital anomalies that can arise in the gallbladder, related to position or formation of the structure of the gallbladder and/or cystic duct. Position anomalies that surgeons may encounter during operations are intro-hepatic, left sided, retro-displaced, transverse, and floating gallbladder [2], as well as structural malformations that include absence or agenesis, double, bilobed, hour-glass, Phrygian cap, rudimentary or congenitally hypoplastic gallbladder, and diverticulum of the gallbladder, while absence of cystic duct, accessory ducts, long cystic duct, low insertion, and atresia are cystic duct malformations [2].

Diverticulum of the gallbladder can be true or false (pseudo-diverticulum) and congenital or acquired. A true diverticulum generally is an outpouching composed of all the alimentary organ layers, while pseudo-diverticulum usually is a herniation of the mucosa and/or submucosa without involving the muscularis layer and/or adventitia. True diverticulum of the gallbladder is very rare, accounting for only 0.06% of all gall-bladder congenital anomalies and 0.0008% of cholecystectomies at the Mayo Clinic [3,4].

Gallbladders associated with a true diverticulum are uncommonly found to be buried in the liver, leading to surgical difficulties during cholecystectomy. Therefore, background knowledge of rare anomalies plays a crucial role in guiding the surgeon to choose the optimal method of management. We also highlight the associated complications that can accompany these anomalies, such as non-specific prolonged ailments, acalculous cholecystitis, cholecystitis and cholelithiasis, recurrent cholangitis, and carcinoma of the gallbladder [5–7].

Case Report

A 38-year-old woman presented to Jubail General Hospital’s surgery clinic with right upper-quadrant (RUQ) pain occasionally radiating to her back. The pain was precipitated by eating a fatty meal and was relieved with analgesics, and was associated with vomiting after meals for 1 month. On physical examination, her vital signs were within normal range, and the abdomen was soft with mild tenderness at the RUQ. There was no jaundice or distress and Murphy’s sign was negative. Ultrasound showed borderline thickness of the gallbladder wall and a 1.8-cm gall stone stuck in the gallbladder neck, as well as sludge and tiny stones along the dependent part of the gallbladder and a small amount of peri-cholecystic fluid.

Laparoscopic cholecystectomy was done and gallbladder tissue was sent to histopathology. Gross examination revealed an already opened gallbladder measuring 8×3 cm, with wall thickness of 0.2 cm. The serosal surface was irregular and congested and the mucosa was congested and velvety. There was an outpouching within the body wall, measuring 2.5×1.5×1 cm, with a 0.6×0.3 cm orifice 5 cm from the cystic duct (Figure 1A, 1B).

Microscopically, sections showed protrusion of the gallbladder wall (muscularis and serosa layers) exhibiting abundant foamy histiocytes, chronic inflammatory cell infiltrate, foreign body giant cells, fibrosis, and hemorrhage. The remaining gall-bladder wall showed hemorrhage, mild inflammatory infiltrate predominantly consisting of lymphocytes, and a hypertrophic muscularis layer with Rokitansky-Aschoff sinuses. Interestingly, unlike the protrusion, the rest of the gallbladder wall did not have xanthogranulomatous inflammation (Figure 1C, 1D). Based on the above findings, the diagnosis of congenital diverticulum with xanthogranulomatous cholecystitis was made.

The postoperative course was uneventful and the patient was discharged the next day, and she was in good condition at the 1-week follow-up later at the surgery clinic.

Discussion

True diverticulum of the gallbladder is rarely reported in the literature. In the last century there have been only 35 documented cases, with an age range of 3–62 years (Table 1). Among these, 17 were males (∼48%), 11 were females (∼31%), and 7 had no reported sex (∼20%). In the current century, males accounted for 93% of cases (14 out of 15). Only 2 pediatric cases are found in the literature – a 3-year-old boy with cholelithiasis and cholecystitis reported in 1947 by Bogatko et al [8] and a 17-year-old girl with recurrent cholecystitis reported in 1998 by Kramer et al [13]. Most of the patients presented with signs and symptoms of cholecystitis, but 9 cases were based on autopsy, and a minority exhibited cholangitis (2 out of 35), pancreatitis (1 out of 35), and carcinoma (1 out of 35). Diverticular size ranged between 0.5 cm to 6 cm, with a tendency to be located at the gastric fundus (∼42%, 15 out of 35), followed by the gastric body (20%, 7 out of 35). A minor subset accounting for 8% (3 out of 35) reported to complicate surgical removal located anterior to the liver, with a tendency to project into it.

True diverticulum is an outpouching of the gallbladder wall involving all 3 histological layers: mucosa, muscularis propria, and adventitia. The pathogenesis is unclear, but is thought to be congenital, which might lead to complications, but there are reported cases without symptoms or complications [5,15]. In contrast to false diverticulum, which is proven to be a consequence of gallstone luminal pressure and inflammation [18], differentiation between the 2 entities could be approached through histological examination. In addition, false diverticula usually tend to be multiple rather than single (as with true diverticulum).

Xanthogranulomatous cholecystitis is a unique type of inflammation that is considered a separate clinical condition rather than a subset of chronic cholecystitis. The pathophysiology of this entity is related to obstruction and stasis caused by gallstones, which leads to protrusion of bile through a mucosal ulceration to the interstitium. Within the interstitium, macrophages are recruited during the inflammatory process. Macrophages are attracted to cholesterol, phospholipids, and fatty acid components of bile, engulfing them to form foamy cells, which are the main histological criteria of xanthogranulomatous inflammation. This morphology can be a pitfall for carcinoma, emphasizing the importance of histological recognition of xanthogranulomatous inflammation [19].

Conclusions

Gallbladders associated with a true diverticulum are uncommonly found to be buried in the liver, leading to surgical difficulties during cholecystectomy. Therefore, background knowledge of occasional anomalies plays a crucial role in guiding the surgeon to choose the optimal method of management.