Mirizzi syndrome is a rare complication (frequency about 1%) of chronic cholecystitis and prolonged cholelithiasis, which consists of inflammatory process of gallbladder wall and direct compression (Mirizzi syndrome type I) or erosion (Mirizzi syndrome type II, III, IV) of the common bile duct and subsequent fistulous formation [6].

After Mirizzi and Mc Sherry [7] classification, the most recent and predominant classification was made by Csendes et al [8]. According to it, Mirizzi syndrome is divided in four types depending on the size of the destruction of the common bile duct (Fig. 4)[4]. A wide communication that included the entire circumference of the CBD (Over 66% of the common bile duct diameter) classifies this case as Mirizzi syndrome type IV [9].

In a large study (219 patients), Csendes et al [8], reported that 11% of their patients with Mirizzi syndrome had type I lesions, 41% had type II lesions, 44% had type III lesions, and 4% had type IV lesions.

Clinical manifestation of this syndrome includes recurrent cholangitis, jaundice, right upper quadrant pain, and abnormal liver biochemistry [10,11]. It is remarkable that this patient was anicteric.

The gold standard in diagnosis of Mirizzi syndrome is ERCP [12]. In this case ERCP was a valuable diagnostic tool that revealed the bile duct stenosis, the impacted gallstone, the wide cholecystocholedochal fistula, and the colonic haustration of the cholecystocolic fistula. Another helpful diagnostic method in this case was Magnetic Resonance Cholangiopancreatography (MRCP). In this case MRCP demonstrated neither the fistulas nor the choledochal stenosis, but it raised a suspicion of an abnormal communication between the gallbladder and the common bile duct. According to the literature, MRCP usually is a sensitive diagnostic tool for the detection of fistulas [13].

Mirizzi syndrome is a rare complication of cholelithiasis that represents a dangerous alteration of the anatomy and bears the potential to lead to significant morbidity and biliary injury, particularly in the laparoscopic era. In this condition the cystic duct usually runs parallel to the CBD (10% of cholangiograms) [14]. Preoperative recognition of this variation is important to avoid inadvertent ligation or severance of the bile duct. An attempt to expose Calot's triangle may lead to severe bile duct injury such as: i) iatrogenic communication between the gallbladder and CBD [4], ii) complete transection of CBD after dissection of the gallbladder neck [2,12,15], iii) tear of CBD [2]. Additionally, a high coincidence of Mirizzi syndrome and gallbladder cancer has been reported in several studies[16-18].

The intraoperative confirmation of Mirizzi syndrome was made after the extraction of the large gallstone. The contracted gallbladder, the inflammatory wall and the subsequent adherence with the common bile duct (CBD) resulted to the wide communication (fistulas diameter: = 3.5 cm) [4]. After temporary stenting of the CBD through the fistula opening we classified the condition as Mirizzi syndrome type IV which represents the most uncommon type [8].

The cholecystoenteric fistula usually develops insidiously, and an association with gallstones is always present. Cholecystoenteric fistula appears in 1.2 to 5% of patients with acute and chronic cholecystitis in a large series of cholecystectomies [19,20]. About 50% of diagnosis for biliary-enteric fistulas is preoperative. ERCP is the most important diagnostic tool in order to identify the presence of biliary-intestinal fistula. Two other significant diagnostic methods MRI and MRCP set up a high index of suspicion revealing the fistulous tract [21]. Subsequently ERCP was almost pathognomic as it demonstrated the colonic haustration. ERCP, barium enema, colonoscopy with contrast fistulography, technetium 99 m scintiscan, and morphine augmented hepatobiliary cholescintigraphy have been proved to be efficacious in the detection of the cholecystocolic fistula [3,22-25]. In this case, colonoscopy was unable to detect the fistulous tract, but the notification of the inflammatory area of the hepatic flexure was very helpful in the overall diagnosis. A causative correlation between Crohn's disease and cholecystocolic fistula formation was also precluded in this case, by colonoscopy [26,27].

The most common type of biliary-enteric fistula is cholecystoduodenal (75%); cholecystocolic is next common (10–20%), with a variety of other types being less frequent (15%) [28-30].

Pneumobilia, atrophic gallbladder with inflamed wall and impacted gallstone as U/S and CT findings, malabsortion with monthly diarrhea as the only clinical manifestation, were the main initial characteristics of this patient [21]. The potential causative agent of this fistula was mechanical erosion by the gallstone between the gallbladder infundibulum and the adjacent colon [31]. Chronic diarrhea, massive lower gastrointestinal hemorrhage, and gallstone ileus are the main severe complications of a cholecystocolic fistula [3,22,31-34]. The fistula's excision and repair of the hepatic flexure with primary closure was finally performed without any further postoperative complications.

The relatively high rate of inadvertent bile duct injury, as previously mentioned, reiterates the danger of Mirizzi syndrome. Laparoscopic cholecystectomy in MS type IV is hazardous and maintains a high threshold to open surgery. ERCP and intraoperative cholangiograms are significant diagnostic tools for MS. The proper surgical treatment of this fistula is partial cholecystectomy and side to side Roux-en-Y choledochojejunostomy. The inflammation and the high risk of fibrosis and stenosis make the primary repair of the fistula hazardous with increased morbidity and mortality rates, indicating Roux-en-Y hepaticojejunostomy the treatment of choice in Type IV Mirizzi syndrome [8,35]. On the other hand cholecystocolic fistula can be diagnosed and even treated by ERCP, and other methods as previously mentioned. Early operation with excision of the fistula and primary closure of the large bowel's defect is the treatment of choice[21,22,33]. Successful laparoscopic repair of isolated cholecystocolic fistulas has also been reported [21].

The rarity of this combination and the precocious recognition remains a challenge for the surgeon. ERCP remains the most powerful diagnostic tool and particularly in this case report approached with high accuracy the correct diagnosis. Primary repair of cholecystocolic fistula and minimal surgical maneuvers of Calot's triangle at the time of the operation for Mirizzi syndrome type IV in order to avoid bile duct injury are two important key points for successful treatment, of these clinical entities.