Porcelain gallbladder

INTRODUCTION — Porcelain gallbladder is associated with chronic gallbladder inflammation. Approximately 95 percent of patients have associated gallstones. Patients with a porcelain gallbladder are often asymptomatic. The diagnosis is usually made incidentally on abdominal imaging. Porcelain gallbladder is associated with an increased risk for gallbladder cancer, but the magnitude of risk appears to be small. This topic will review the epidemiology, clinical presentation, diagnosis, and management of porcelain gallbladder. Gallbladder cancer, uncomplicated gallstone disease, acalculous cholecystitis, and acute cholecystitis are discussed separately. (See "Gallbladder cancer: Epidemiology, risk factors, clinical features, and diagnosis" and "Overview of gallstone disease in adults" and "Choledocholithiasis: Clinical manifestations, diagnosis, and management" and "Acalculous cholecystitis: Clinical manifestations, diagnosis, and management".)

TERMINOLOGY AND SUBTYPES — Porcelain gallbladder is characterized by calcification of the gallbladder wall [1]. The term porcelain gallbladder has been used to describe the bluish discoloration and brittle consistency of the gallbladder wall associated with this condition [2]. Porcelain gallbladder is classified based upon the extent of calcification [3]:

●Complete intramural calcification – A continuous band of calcium infiltrates and replaces the muscular layer of the gallbladder wall. It is accompanied by sloughing of the mucosal epithelium and dense fibrosis of the entire gallbladder wall.

●Selective mucosal calcification – Calcification of the gallbladder wall is less extensive or segmental with flecks of calcium in the mucosa of the gallbladder wall.

EPIDEMIOLOGY

Incidence — Porcelain gallbladder is rare and is detected in 0.06 to 0.08 percent of cholecystectomy specimens [4]. It has a female preponderance (5:1) and is usually diagnosed in the sixth decade of life [5].

Risk of malignancy — The incidence of gallbladder carcinoma in patients with porcelain gallbladder is approximately 2 to 3 percent [6]. In a systematic review of seven series that included 60,665 patients who underwent cholecystectomy, 140 (0.2 percent) had porcelain gallbladder [6]. Of those with porcelain gallbladder, 21 (15 percent) had gallbladder cancer. However, the high rates of gallbladder cancer were seen primarily in older studies. Among the 85 patients with porcelain gallbladder from studies reported between 2001 and 2011, gallbladder cancer was seen in two (2.3 percent; range 0 to 5 percent for the individual studies).

Patients with selective mucosal calcification of the gallbladder wall appear to be at higher risk for gallbladder cancer compared with those in whom the gallbladder wall is completely calcified (complete type) [2-4,6-9]. In a series of 44 patients with gallbladder calcification who underwent cholecystectomy, 17 had complete intramural calcification, and 27 had selective (incomplete) mucosal calcification [8]. Gallbladder cancer was present in two of the patients with selective mucosal calcification (7 percent) and in none of the patients with complete calcification. A potential explanation for the difference in the risk of gallbladder cancer is that since gallbladder cancer is mucosal in origin and patients with the complete type of porcelain gallbladder have a low risk due to loss of mucosal epithelium. (See 'Terminology and subtypes' above and 'Ultrasonography' below.)

The most common type of malignancy associated with porcelain gallbladder is adenocarcinoma, which is seen in nearly 80 percent of patients with porcelain gallbladder who develop gallbladder cancer. Squamous cell carcinoma and adenosquamous carcinoma have also been reported [10]. (See "Gallbladder cancer: Epidemiology, risk factors, clinical features, and diagnosis".)

PATHOGENESIS — The pathogenesis of gallbladder wall calcification is controversial. Porcelain gallbladder is associated with cholelithiasis in more than 95 percent of patients [7]. It has been suggested that the chronic inflammation due to gallstones results in scarring, hyalinization, and calcification [5]. An alternative hypothesis is that cystic duct obstruction leads to bile stagnation within the gallbladder followed by mucosal precipitation of calcium carbonate salts [7].

CLINICAL PRESENTATION

Clinical features — Patients are often asymptomatic, but occasionally present with symptoms due to complications of gallstone/gallbladder disease. This includes right upper quadrant/epigastric abdominal pain, jaundice, or fever due to common duct obstruction, cholangitis, or pancreatitis. Rarely, the gallbladder may be palpable as a firm, nontender mass in the right upper quadrant.

Incidental imaging finding — Porcelain gallbladder may be detected on abdominal imaging (abdominal radiographs, ultrasound, or abdominal computed tomography [CT] scan). Plain abdominal radiographs may reveal curvilinear or rim-like calcifications in the gallbladder wall (image 1) [4]. However, similar findings can also be seen if the gallbladder is full of bile that is supersaturated with calcium salts (milk of calcium bile) or due to calcifications in gallstones, renal cysts, chest wall masses, and degenerative cystic lesions of the pancreas and adrenal gland. Abdominal radiographs are not diagnostic for porcelain gallbladder due to their low sensitivity and specificity. Diagnostic imaging modalities for porcelain gallbladder include abdominal CT scan and ultrasound. (See 'Diagnostic imaging' below.)

DIAGNOSIS — Porcelain gallbladder is usually discovered incidentally on abdominal imaging. The diagnosis is established by the presence of curvilinear or granular calcification of the gallbladder wall on abdominal computerized tomogram or ultrasound. In patients in whom porcelain gallbladder is suspected based on an abdominal radiograph or diagnosed on abdominal ultrasound, we perform an abdominal computed tomography because it has a high sensitivity for calcification and gallbladder cancer [4]. A definitive diagnosis of porcelain gallbladder is made by histopathological evaluation of the gallbladder after cholecystectomy. (See "Gallbladder cancer: Epidemiology, risk factors, clinical features, and diagnosis", section on 'Diagnostic evaluation'.)

Diagnostic imaging

Computed tomography — On abdominal computed tomography (CT) scan in patients with porcelain gallbladder, the gallbladder wall appears as a calcified rim with a dark central bile-filled region (image 2). Findings suggestive of gallbladder cancer that may be visualized on abdominal CT include a polypoid mass protruding into the lumen or completely filling it, focal or diffuse thickening of the gallbladder wall, or a mass in the gallbladder fossa with the gallbladder itself being indiscernible; liver invasion, suspected nodal involvement, or distant metastases [4]. The accuracy of CT scan in diagnosing porcelain gallbladder was evaluated in a study that evaluated 133 cases that were initially reported as porcelain gallbladder [11]. Radiology was reviewed by two independent radiologists and the diagnosis was confirmed by surgery/pathology or follow-up imaging. The diagnosis of porcelain gallbladder was confirmed in 90 of 133 cases (68 percent); thirty-two percent were false positive. Misleading causes included stones filling the whole gallbladder lumen (91 percent), sludge (7 percent), and mucosal enhancement (5 percent). Six percent of cases had concurrent gallbladder cancer at the outset. (See "Gallbladder cancer: Epidemiology, risk factors, clinical features, and diagnosis", section on 'Computed tomography and magnetic resonance imaging'.)

Ultrasonography — The sonographic appearance of porcelain gallbladder depends on the extent of calcification. When the gallbladder wall is heavily calcified and the wall is diffusely involved, calcification appears as an echogenic arc with clean posterior acoustic shadowing. Less extensive calcification results in partial shadowing such that the posterior wall of the gallbladder remains visible. In early cases, only segments of the gallbladder wall may be affected.

Three distinct sonographic patterns have been described in patients with porcelain gallbladder [4]:

●Type I – A hyperechoic semilunar appearance with posterior acoustic shadowing (image 3).

●Type II – A biconvex curvilinear echogenic appearance with variable acoustic shadowing.

●Type III – Irregular clumps of echoes with posterior acoustic shadowing.

Type I corresponds to the complete intramural calcification. Type II and III correspond to selective mucosal calcification. (See 'Terminology and subtypes' above.)

Histopathology — Porcelain gallbladder has two histologic patterns:

●Broad continuous band of calcification within the muscularis. This appears radiologically as large plaque-like areas.

●Multiple punctate calcifications in the glandular spaces of the mucosa. This pattern results in the radiographic appearance of granular calcification (picture 1).

DIFFERENTIAL DIAGNOSIS — The differential diagnosis of porcelain gallbladder on imaging includes cholelithiasis and emphysematous cholecystitis. These entities can be distinguished based on abdominal ultrasound. However, in some cases, abdominal computed tomography may be required.

●Cholelithiasis – A stone-filled gallbladder is another cause of shadowing in the gallbladder fossa. However, in patients with cholelithiasis there is a thin hypoechoic bile space between the gallbladder wall and the gallstone echo. The presence of a wall echo shadow complex is suggestive of a stone-filled collapsed gallbladder. (See "Overview of gallstone disease in adults", section on 'Clinical manifestations'.)

●Emphysematous cholecystitis – Patients with emphysematous cholecystitis may also have an echogenic crescent in the gallbladder fossa. Ring-down shadows from gas within the gallbladder wall on ultrasound can mimic calcification in patients with porcelain gallbladder. However, emphysematous cholecystitis produces dirty acoustic shadowing.

MANAGEMENT

Suggested approach — Our approach to the management of porcelain gallbladder is based on the following:

●Symptoms or complications of gallstone/gallbladder disease. This includes biliary-type pain, common duct obstruction, cholangitis, or recurrent pancreatitis.

●Pattern of calcification (selective mucosal calcification versus complete mural calcification).

●Patient's age and comorbid medical conditions.

The rationale for our approach is based on data that demonstrate that the risk of gallbladder cancer is low and that among patients with porcelain gallbladder the risk of cancer appears to be increased in patients with selective mucosal calcification as compared with complete mural calcification. (See 'Risk of malignancy' above.)

●Symptomatic or selective mucosal calcification – We refer patients with complete mural calcification for cholecystectomy if they are symptomatic. We suggest surgery for all patients with selective mucosal calcification, given their increased risk for gallbladder cancer. (See "Treatment of acute calculous cholecystitis" and "Approach to the management of gallstones" and 'Risk of malignancy' above.)

●Asymptomatic and complete mural calcification – Among patients with complete mural calcification who are asymptomatic, particularly those who are young or who have good functional status, we offer prophylactic cholecystectomy, despite limited data regarding the true risk of gallbladder cancer in such patients, because the prognosis for gallbladder cancer is poor. (See "Prognosis and adjuvant treatment for localized, resected gallbladder cancer", section on 'Prognosis and patterns of spread'.)

In all patients with porcelain gallbladder who do not undergo cholecystectomy, we suggest conservative management. (See 'Conservative management' below.)

The management of porcelain gallbladder is controversial. Historically, porcelain gallbladder has generally been seen as an indication for cholecystectomy, even in asymptomatic patients. However, given that the risk appears to be lower than previously thought, some experts suggest that patients with porcelain gallbladder be observed, with surgery being reserved for those with conventional indications for cholecystectomy [6,12]. Others experts have challenged this recommendation, noting that the rate of gallbladder cancer seen in more recent studies (2 to 3 percent) is high enough to justify prophylactic cholecystectomy [13]. (See "Gallbladder cancer: Epidemiology, risk factors, clinical features, and diagnosis" and 'Epidemiology' above and "Laparoscopic cholecystectomy", section on 'Indications'.)

Surgery — Laparoscopic cholecystectomy is feasible in patients with porcelain gallbladder despite the presence of a fibrotic gallbladder wall, especially in patients with a long cystic duct and well-defined biliary anatomy [14,15]. Dissection can initially be performed laparoscopically with the plan to convert to an open procedure if necessary [16]. The surgeon should maintain a high index of suspicion for gallbladder cancer. A frozen section should be performed of any suspicious areas of the gallbladder. The management of gallbladder cancer is discussed in detail, separately. (See "Surgical management of gallbladder cancer".)

Conservative management — Patients with porcelain gallbladder who do not undergo cholecystectomy should be educated about the symptoms of gallstone/gallbladder disease and its complications and instructed to seek medical attention if the symptoms occur. We do not routinely screen for gallbladder cancer [17]. However, if imaging of the gallbladder is indicated, we perform contrast-enhanced computed tomography. Abdominal ultrasound is limited by gallbladder wall calcifications which obscure the gallbladder contents. (See 'Clinical features' above.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Cholecystitis and other gallbladder disorders".)

SUMMARY AND RECOMMENDATIONS

●Porcelain gallbladder is characterized by calcification of the gallbladder wall. The term porcelain gallbladder has been used to describe the bluish discoloration and brittle consistency of the gallbladder wall associated with this condition. Porcelain gallbladder is classified based upon the extent of calcification into complete intramural calcification or selective mucosal calcification. (See 'Terminology and subtypes' above.)

●The pathogenesis of gallbladder wall calcification is controversial. As porcelain gallbladder is associated with cholelithiasis in more than 95 percent of patients, it is hypothesized that calcification results from chronic inflammation due to gallstones or cystic duct obstruction, leading to bile stagnation and mucosal precipitation of calcium carbonate salts. (See 'Pathogenesis' above.)

●Porcelain gallbladder is detected in 0.06 to 0.08 percent of cholecystectomy specimens. The incidence of gallbladder carcinoma in patients with a calcified gallbladder is approximately 2 to 3 percent. Limited observational data suggest that patients with selective mucosal calcification appear to be at higher risk for gallbladder cancer compared with those with complete intramural calcification. (See 'Epidemiology' above.)

●Patients are often asymptomatic but occasionally present with symptoms due to complications of gallstone/gallbladder disease. This includes right upper quadrant/epigastric abdominal pain, jaundice, or fever due to common duct obstruction, cholangitis, or pancreatitis. (See 'Clinical features' above.)

●Porcelain gallbladder is usually discovered incidentally on abdominal imaging. The diagnosis is established by the presence of curvilinear or granular calcification of the gallbladder wall on abdominal computerized tomogram or ultrasound. In patients in whom porcelain gallbladder is suspected based on an abdominal radiograph or diagnosed on abdominal ultrasound, we perform an abdominal computed tomography. A definitive diagnosis of porcelain gallbladder is made by histopathological evaluation of the gallbladder after cholecystectomy. (See 'Diagnosis' above.)

●Our approach to the management of porcelain gallbladder is based on the following:

•Symptoms or complications of gallstone/gallbladder disease. This includes biliary-type pain, common duct obstruction, cholangitis, or recurrent pancreatitis.

•Pattern of calcification (selective mucosal calcification versus complete mural calcification).

•Patient’s age and comorbid medical conditions.

●We suggest surgery for patients with selective mucosal calcification or incomplete mural calcification, regardless of symptoms, provided they are good surgical candidates (Grade 2C).

●We refer patients with complete mural calcification for cholecystectomy if they are symptomatic. We also discuss prophylactic cholecystectomy with asymptomatic patients who are young or have good functional status, despite limited data regarding the true risk of gallbladder cancer in such patients, because the prognosis for gallbladder cancer is poor. Patients with porcelain gallbladder who do not undergo cholecystectomy should be educated about the symptoms of gallstone/gallbladder disease and its complications and instructed to seek medical attention if symptoms occur. (See 'Suggested approach' above.)