You are in: eMedicine Specialties > Radiology > GASTROINTESTINAL Porcelain GallbladderArticle Last Updated: Feb 12, 2008AUTHOR AND EDITOR INFORMATIONAuthor: Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR, LRCP, Chairman of Medical Imaging, Professor of Radiology, NGHA, King Fahad National Guard Hospital, King Abdulaziz Medical City, Riyadh, Saudi Arabia Ali Nawaz Khan is a member of the following medical societies: American Institute of Ultrasound in Medicine, Radiological Society of North America, Royal College of Physicians, Royal College of Physicians and Surgeons of the United States, Royal College of Radiologists, and Royal College of Surgeons of England Coauthor(s): Margaret Aird, MBChB, FRCR, Consulting Staff, Department of Radiology, Wythenshawe Hospital; Sumaira MacDonald, MBChB, PhD, MRCP, FRCR, Lecturer, Sheffield University Medical School; Endovascular Fellow, Sheffield Vascular Institute; David Sherlock, MBBS, FRCS, Consulting Staff, Department of Surgery, North Manchester General Hospital, Christie Hospital Editors: Neela Lamki, MD, Professor, Department of Radiology, Sultan Qaboos University, Oman; Adjunct Professor, Department of Radiology, Baylor College of Medicine; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Abraham H Dachman, MD, FACR, Professor, Department of Radiology, The University of Chicago School of Medicine; Director of CT, Department of Radiology, The University of Chicago Hospitals; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; John Karani, MBBS, FRCR, Consulting Staff, Department of Radiology, King's College Hospital, London Author and Editor Disclosure Synonyms and related keywords: calcified gallbladder, calcifying cholecystitis, cholecystopathia chronica calcarea, blue gallbladder wall, gallbladder discoloration, brittle gallbladder, calcified gallbladder, gallbladder wall calcification INTRODUCTIONBackgroundExtensive calcium encrustation of the gallbladder wall has been variably termed calcified gallbladder, calcifying cholecystitis, or cholecystopathia chronica calcarea. The term "porcelain gallbladder" has been used to emphasize the blue discoloration and brittle consistency of the gallbladder wall at surgery. Some authorities eschew these terms and instead call all calcified gallbladders "porcelain gallbladders." The true incidence of porcelain gallbladder is unknown, but it is reported to be 0.6-0.8%, with a male-to-female ratio of 1:5. Most porcelain gallbladders (90%) are associated with gallstones.1 Patients with porcelain gallbladder are usually asymptomatic, and the condition is usually found incidentally on plain abdominal radiographs, sonograms, or computed tomography (CT) images. Surgical treatment of porcelain gallbladder is based on results from studies performed in 1931 and 1962, which revealed an association between porcelain gallbladder and gallbladder carcinoma. Porcelain gallbladder is an uncommon condition; recognizing the clinical and imaging characteristics of the disease is important because of the high frequency (22%) of adenocarcinoma in porcelain gallbladder.2 Nonetheless, the causal relationship between porcelain gallbladder and malignancy has not been established. Surgery should not be delayed even if the patient is asymptomatic, because the occurrence of carcinoma in porcelain gallbladder is remarkably high.3 PathophysiologyHistologically, flakes of dystrophic calcium exist within the chronically inflamed gallbladder wall. The muscular wall of the gallbladder undergoes fibrotic changes. Microliths are diffusely scattered throughout the mucosa, submucosa, and glandular spaces, as well as in the Rokitansky-Aschoff sinuses. Calcification occurs in 2 forms: (1) a broad continuous band of calcification in the muscularis and (2) multiple punctate calcifications in the mucosa and glandular spaces of the mucosa. Gallstones are present in 90% of patients, and hydrops can obstruct the cystic duct. Most authorities consider gallbladder wall calcification to be secondary to a low-grade inflammation, but intramural hemorrhage and an imbalance in calcium metabolism are implicated as well. Rooholamini et al retrospectively studied 59 cases of histologically proved gallbladder carcinoma and found an association with porcelain gallbladder in 4% of cases.5 Calcification in the right upper quadrant of the abdomen has several causes. Calcification can be categorized by the organ system in which it appears; for example, calcification can affect the liver, gallbladder, right kidney, digestive tract, peritoneal cavity, right adrenal gland, and retroperitoneum. Diseases associated with these organs include large gallbladder opaque calculi, milk-of-calcium bile (see Image 9), echinococcal cysts (see Images 10-11), schistosomiasis and other granulomatous diseases,7 old liver infarcts that have healed (see Image 12), calcified renal cysts, renal calculi, calcified nonparasitic liver cysts, primary and metastatic liver tumors, benign liver tumors, and calcification in old adrenal hemorrhage and adrenal masses. FrequencyUnited StatesThe overall incidence of porcelain gallbladder in the United States appears to be identical to the international incidence (see International, below). InternationalBecause most cases of gallbladder calcification are not reported, determining the exact incidence is difficult; however, studies of cholecystectomy specimens reveal a 0.6-0.8% occurrence rate for extensive mural calcification.1 Mortality/MorbidityThe clinical importance of porcelain gallbladder lies in its significant association with gallbladder carcinoma. Because patients with gallbladder carcinoma usually have a poor prognosis, most authors agree that carcinoma occurs in association with porcelain gallbladder with sufficient frequency to warrant prophylactic cholecystectomy. RaceNo racial predilection is reported. In regions with a high incidence of gallstone disease, a high incidence of porcelain gallbladder might be expected; however, this relationship has not been demonstrated to date. Calcified hydatid cysts in the liver are fairly common in endemic areas, such as the Middle East, Eastern and Mediterranean Europe, and North Africa. These cysts can mimic porcelain gallbladder on plain abdominal radiographs; however, the patient's country of origin or history of travel to endemic regions can suggest the diagnosis of calcified hydatid cysts. Ultrasonography will reveal the true gallbladder. SexThe male-to-female ratio is 1:5.1 AgeThe mean age of patients is 54 years, with an age range of 38-70 years. Porcelain gallbladder is exceptionally rare in children; the only case described is of a 10-year-old girl who underwent a prophylactic cholecystectomy.8 Clinical DetailsCharacteristically, the condition is clinically covert, although a palpable mass may occasionally be found. The diagnosis of porcelain gallbladder is frequently made because of incidental findings on plain abdominal radiographs, sonograms, or CT images; sometimes, a mass may be palpable in the right upper quadrant of the abdomen. The association between gallbladder malignancy and porcelain gallbladder was established on the basis of the results of studies performed in 1931 and 1962.4 Since then, sporadic case reports and collections of cases have appeared in the literature, and their findings have reinforced this association. A study conducted by Towfigh et al contradicts this time-honored view. The authors reviewed the medical records of 10,741 patients who underwent cholecystectomies in the years 1955-1998. Pathology slides were evaluated for evidence of calcification and gallbladder carcinoma. The incidence of porcelain gallbladder was 0.14% (15 patients) in the series; 10 patients had symptoms suggestive of biliary colic or cholecystitis, and the diagnosis was incidental in 5. All specimens examined showed histologic evidence of chronic cholecystitis and partial calcification of the gallbladder wall. Gallstones were found in 60% of the patients, but none had gallbladder carcinoma. During the same period, 0.82% of the patients had gallbladder carcinoma, none of whom had gallbladder wall calcification. The study did not reveal carcinoma in patients with porcelain gallbladder. In addition, none of the patients with gallbladder carcinoma had porcelain gallbladder. The authors concluded that with a better understanding of the natural history of porcelain gallbladder, patient treatment may change; however, until further studies confirm these findings, the importance of surgical treatment cannot be overemphasized, considering the frequency of carcinoma associated with porcelain gallbladder (as reported in previous studies). Most authors agree that carcinoma occurs in association with porcelain gallbladder with sufficient frequency to warrant prophylactic cholecystectomy. Most carcinomas associated with porcelain gallbladder are diffusely infiltrating adenocarcinomas, although squamous cell carcinoma has been described as well. In rare cases, calcification that has precipitated in mucus within neoplastic glandular tissue may also be visible on plain radiographs; this calcification can mimic a carcinoma that is developing in a porcelain gallbladder. Preferred ExaminationAlthough most porcelain gallbladders are incidentally seen on plain abdominal radiographs, the definition and sensitivity provided by CT scanning appears to be far superior to the definition and sensitivity of radiography. CT is also superior to radiography for staging gallbladder carcinoma when it is a complication of porcelain gallbladder. Sonograms do not depict porcelain gallbladder as well as CT scans do; sonographic findings can mimic those seen with a nonfunctioning gallbladder, large calculus, and emphysematous cholecystitis. (Patients with emphysematous cholecystitis usually have diabetes with no point tenderness [ie, diabetic neuropathy]. In one third of these patients, the white blood cell [WBC] count is within the normal range. High-level echoes that outline the gallbladder result from gas within the gallbladder wall. With emphysematous cholecystitis, the male-to-female ratio is 5:1.) Occasionally, hepatobiliary surgeons may order angiograms when a malignant change has occurred and staging is required. Limitations of TechniquesIn porcelain gallbladder, plain radiographic findings are usually straightforward and are not often confused with findings related to other causes of calcification in the right upper quadrant. If doubt exists, cross-sectional imaging with a modality such as ultrasonography or CT can more accurately depict calcification in the appropriate organ.10 Porcelain gallbladder must be distinguished from large solitary calcified gallstones, which are seldom as large as porcelain gallbladders; however, exceptions can make a definite diagnosis difficult. Milky bile syndrome is characterized by radiopaque material that causes sufficient opacification of the gallbladder to cause it to be depicted on plain abdominal radiographs. Calculi in the cystic duct and/or Hartmann pouch usually obstruct the gallbladder, and the gallbladder wall will appear inflamed. The spontaneous expulsion of limy bile along with gallbladder calculi has been reported. The puttylike radiopaque material consists of calcium carbonate or, less commonly, calcium phosphate or calcium bilirubinate. Calcification of the gallbladder wall or milk-of-calcium bile may have identical appearances on sonograms; therefore, plain radiography is important in distinguishing these entities. Calcified hydatid cysts in the liver are fairly common in endemic areas, such as the Middle East, Eastern and Mediterranean Europe, and North Africa. These cysts can mimic porcelain gallbladder on plain abdominal radiographs; however, the patient's country of origin or history of travel to endemic regions suggest the diagnosis of calcified hydatid cysts. Ultrasonography will reveal the true gallbladder. Fataar et al described calcified gallbladder granulomas in schistosomal infestation that are dense enough to be seen on abdominal radiographs.7 Serpiginous calcification, as seen on plain radiographs of the abdomen in the region of the gallbladder neck, appears to indicate gallbladder schistosomiasis in patients from endemic areas.7 Calcifications in nonparasitic hepatic and renal cysts, in the adrenal gland, and in liver tumors usually are dissimilar to those in porcelain gallbladder. If confusion remains, sonograms or CT scans can be used to clarify the issue. Emphysematous cholecystitis can mimic porcelain gallbladder on sonograms; however, their clinical presentation is distinct from that of porcelain gallbladder. Ring-down shadows from gas within the gallbladder wall or lumen may be evident, and plain radiographs may show gas within the gallbladder fossa. DIFFERENTIALSGallbladder, Carcinoma Other Problems to Be ConsideredRight upper quadrant calcifications
RADIOGRAPHFindingsPlain abdominal radiographs may demonstrate curvilinear calcification in the right hypochondrium, which corresponds to the location and shape of the gallbladder (see Image 1). The thickness of the calcification is variable; it may be thin and faintly visible or amorphous, patchy, and thick. The gallbladder may be large, but its size can vary considerably. Oral cholecystography reveals a nonfunctioning gallbladder. Degree of ConfidenceAlthough plain abdominal radiographs have been a standard technique for demonstrating right upper quadrant calcification, sonograms and CT scans appear to be more sensitive (see Image 3). In some patients, plain abdominal radiographs may show no abnormalities. It is no longer considered adequate to use only plain radiographs when evaluating possible calcifications in the upper abdomen.10 False Positives/NegativesCalcification in the right upper quadrant of the abdomen has several causes. Calcification can be categorized by the organ system in which it appears; for example, calcification can affect the liver, gallbladder, right kidney, digestive tract, peritoneal cavity, right adrenal gland, and retroperitoneum. Diseases that are associated with these organs include large gallbladder opaque calculi, milk-of-calcium bile, echinococcal cysts, schistosomiasis and other granulomatous disease, old liver infarcts that have healed, calcified renal cysts, renal calculi, calcified nonparasitic liver cysts, primary and metastatic liver tumors, benign liver tumors, and calcification in old adrenal hemorrhage and adrenal masses. In porcelain gallbladder, plain radiographic findings are usually straightforward and are not often confused with findings related to other causes of calcification in the right upper quadrant. Calcified gallbladder granulomas in schistosomal infestation that are dense enough to be seen on abdominal radiographs have been described. Serpiginous calcification on plain abdominal radiographs in the region of the neck of the gallbladder appears to indicate gallbladder schistosomiasis in patients from endemic areas.7 CT SCANFindingsCT scans of porcelain gallbladder will show a curvilinear or rim calcification, which is usually associated with calculi in the anatomic location of the gallbladder. With gallbladder carcinoma (see Images 5-8), an associated pericholecystic mass may be visualized and intrahepatic metastases and hilar lymphadenopathy may be evident. Degree of ConfidenceAlthough plain abdominal radiographs have been the standard technique for demonstrating right upper quadrant calcification, CT scans appear to be more sensitive than radiographs. In some patients, plain abdominal radiographs may show no abnormalities. It is no longer considered adequate to use only plain radiographs when evaluating possible calcifications in the upper abdomen.10 False Positives/NegativesCalcification in the right upper quadrant of the abdomen has several causes. Calcification can be categorized by the organ system in which it appears; for example, calcification can affect the liver, gallbladder, right kidney, digestive tract, peritoneal cavity, right adrenal gland, and retroperitoneum. Diseases that are associated with these organs include large gallbladder opaque calculi, milk-of-calcium bile, echinococcal cysts, schistosomiasis and other granulomatous disease, old liver infarcts that have healed, calcified renal cysts, renal calculi, calcified nonparasitic liver cysts, primary and metastatic liver tumors, benign liver tumors, and calcification in old adrenal hemorrhage and adrenal masses. Although calcification seen on plain abdominal images can possibly be confused with porcelain gallbladder, the anatomic location, as viewed on CT scans, depicts calcification in the gallbladder fossa. This finding is less likely to create confusion with other findings of upper abdominal calcification. MRIFindingsTo the authors' knowledge, magnetic resonance imaging (MRI) findings in porcelain gallbladder have not been reported. ULTRASOUNDFindingsFour distinct patterns have been identified in ultrasonography of porcelain gallbladder, and they are as follows: (1) a hyperechoic semilunar structure with posterior acoustic shadowing that simulates a stone-filled gallbladder devoid of bile (see Image 2), (2) a biconvex curvilinear echogenic structure with variable acoustic shadowing, (3) an irregular clump of echoes with posterior acoustic shadowing (see Image 4), and (4) an echogenic gallbladder wall without acoustic shadowing. In addition, a spiral image may show findings similar to those seen in scleroatrophic gallbladder lithiasis.11 Degree of ConfidenceAlthough plain abdominal radiographs have been the standard technique for demonstrating right upper quadrant calcification, sonograms appear to be more sensitive than radiographs.10 False Positives/NegativesIn porcelain gallbladder, plain radiographic findings are usually straightforward and are not often confused with findings related to other causes of calcification in the right upper quadrant. If doubt exists, cross-sectional imaging with a modality such as ultrasonography or CT can more accurately depict calcification in the appropriate organ.10 Porcelain gallbladder must be distinguished from large solitary calcified gallstones, which seldom are as large as a porcelain gallbladder; however, exceptions can make a definite diagnosis difficult. Confusion may also arise with emphysematous cholecystitis and a stone-filled gallbladder when only sonographic criteria are used; however, emphysematous cholecystitis usually causes dirty shadowing, which may be interrupted by ring-down shadows caused by gas within the wall or lumen of the gallbladder. A stone-filled gallbladder results in the wall-echo-shadow sign. The wall-echo-shadow sign consists of 2 parallel echogenic lines separated by a hypoechoic space with distal shadowing. The more superficial echogenic line is a result of the interface of the gallbladder wall and the liver; the hypoechoic area is the gallbladder wall itself. The deep echogenic line is the anterior surface of the gallstone(s). NUCLEAR MEDICINEFindingsRadionuclide uptake images obtained with technetium-99m hepatoiminodiacetic acid (HIDA) demonstrate a nonfunctioning gallbladder. Degree of ConfidenceNuclear medicine findings are nonspecific because HIDA uptake shows nonfunction in acute cholecystitis and chronic cholecystitis. HIDA uptake scanning is not a recommended imaging procedure for the assessment of porcelain gallbladder. ANGIOGRAPHYFindingsAngiography is useful when findings are complicated by carcinoma of the gallbladder. Although carcinoma tends to be avascular, angiography can be used to evaluate the hepatic artery and portal vein for occlusion and/or encasement. This information is useful when surgery is contemplated. Degree of ConfidenceAngiography is used for root mapping of the blood supply of the liver and gallbladder, for which angiography has good accuracy. Portal venous and/or hepatic arterial occlusion or encasement also can be demonstrated fairly well on angiograms. False Positives/NegativesHepatic arterial and/or portal venous occlusion or encasement can occur as a consequence of benign inflammatory diseases such as pancreatitis. INTERVENTIONRadiologic intervention is possible when an associated adenocarcinoma exists; the tumor can cause bile duct obstruction as a result of direct invasion or obstruction of the ducts as a consequence of lymph node metastases.13 The goal of intervention is to maintain biliary patency by means of endoscopic retrograde cholangiopancreatography or external and/or internal biliary drainage by using percutaneous transhepatic cholangiography. The spontaneous resolution of porcelain gallbladder has not been described; however, spontaneous resolution is a rare occurrence in milky bile syndrome. MULTIMEDIA
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