CASE 14309 Published on 15.01.2017

Pyloric-type gallbladder adenoma: ultrasound, CT and MRI findings

Section

Abdominal imaging

Case Type

Clinical Cases

Authors

Tonolini Massimo, MD (1); Crespi Michele, MD (2); Matacena Giovanni, MD (1)

"Luigi Sacco" University Hospital, Radiology (1) and Surgery (2) Departments
Via G.B. Grassi 74 20157 Milan, Italy; Email:mtonolini@sirm.org

Patient

39 years, female

Categories

Area of Interest Biliary Tract / Gallbladder ; Imaging Technique Ultrasound, CT, MR

Procedure Diagnostic procedure, Cholangiography ; Special Focus Dysplasias, Neoplasia ;

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Clinical History

A middle-aged woman presented with a previous hysterectomy for benign disease, and is currently suffering from alimentary vomiting and upper abdominal pain since 24 hours, without peritonism.
Urgent laboratory tests revealed leukocytosis (24.000cells/mmc), bilirubin 3 mg/dL, hyperlipasemia (1864 U(L), raised C-reactive protein (35 mg/L), aspartate- (747 U/L) and alanine-aminotransferase (786 U/L).

Imaging Findings

Ultrasound (Fig.1) showed a 3.6-cm nonmobile lobulated intraluminal gallbladder mass, isoechoic with the adjacent fatty liver, overlying the continuous non-thickened gallbladder wall.
The next day, CT (Fig.2) showed peripancreatic oedema, normal pancreatic size and enhancement consistent with oedematous acute pancreatitis. The gallbladder mass showed solid precontrast attenuation and moderate enhancement with an identifiable vascular pedicle.
Symptoms and laboratory changes regressed within a week on conservative treatment.
MRI (Figs.3, 4) showed non-dilated common bile duct filling defects consistent with sludge, blood clots or fragments of the gallbladder mass. The latter showed low T2-, low-to-intermediate T1 signal intensity, unrestricted diffusion, moderate and persistent enhancement. The gallbladder wall and adjacent liver parenchyma appeared normal.
Cholecystectomy with en-bloc resection of IVb-V liver segments and nodal dissection was performed. Pathology diagnosed sessile mucosal proliferation with histological features of tubular adenoma with pyloric metaplasia, without signs of dysplasia or malignancy.

Discussion

Termed gallbladder polyps (GP), lesions protruding into the lumen from the gallbladder wall are encountered in up to 5-7% of the general population, often incidentally during ultrasonographic studies for unrelated reasons. GPs encompass pseudotumours (cholesterol polyps, adenomyomatosis and inflammatory polyps in descending order of frequency), benign and malignant tumours [1, 2].
Gallbladder adenomas (GAs) are rare benign epithelial tumours, which account for approximately 2% of GPs and are found in 0.15% of cholecystectomy specimens. GAs occur in adulthood and advanced age and are asymptomatic, except when obstructing the gallbladder infundibulum; symptoms are generally due to associated lithiasis or chronic inflammation. GAs are almost invariably solitary lesions measuring up to 2 cm in size, and are histologically categorized as pyloric, intestinal, foveolar and biliary. The former type is characterised by dilated glandular structures, metaplastic pyloric-type gastric cells staining positive for mucin, may harbour dysplasia (in 27% of cases) and occasionally foci of carcinoma in larger lesions. Some Authors considered GAs premalignant after observing cases of malignant transformation and Adenomatous residues in invasive carcinomas; conversely recent reports claim that a dysplasia-to-carcinoma sequence is more probable [3-6].
Albeit 95% of GPs are non-neoplastic, radiologists should suggest whether a GP requires surgery, follow-up or nothing; unfortunately the differentiation between benign GPs over 1 cm and protruding forms of gallbladder carcinoma (P-GC) is challenging. Sonographically GAs show homogeneous isoechoic appearance, are confined to the lumen with thin underlying gallbladder wall. CT features suggestive of malignancy include size >1.5 cm, irregular surface, mural thickening, and perception on unenhanced images [7-12].
As this case exemplifies, MRI is helpful in the differentiation of GA from P-GC, the latter characterised by mural thickening, heterogeneously increased T2 signal intensity, prolonged enhancement. Conversely, GA shows moderate homogeneous enhancement with subsequent washout, smooth underlying wall with normal thickness. Diffusion-weighted imaging further improves diagnostic accuracy, since apparent diffusion coefficient (ADC) values of P-GC generally measure 1.31-1.46 and are significantly lower than those of GAs (1.72-2.66 x10-3 mm2/s) [8-10, 13-15].
Accurate imaging is crucial for correct surgical choice and planning. Cholecystectomy is recommended for GPs greater than 1 cm with symptoms, patient age over 50 years, concurrent gallstones or interval growth. Radical surgery including en-bloc resection of adjacent liver and regional lymphadenectomy is required when malignancy cannot be excluded [1,2].

Differential Diagnosis List

Pyloric-type tubular adenoma of the gallbladder.

Immobile

adherent gallstones/gallbladder sludge ball

Cholesterol polyp

Inflammatory polyp

Protruding type gallbladder carcinoma

Chronic Cholecystitis

Gallbladder lymphoma (rare)

Metastatic gallbladder melanoma (rare)

Final Diagnosis

Pyloric-type tubular adenoma of the gallbladder.

References

[1] Terzi C, Sokmen S, Seckin S, et al (2000) Polypoid lesions of the gallbladder: report of 100 cases with special reference to operative indications. Surgery 127:622-627. (PMID: 10840356)

[2] Wiles R, Varadpande M, Muly S, et al (2014) Growth rate and malignant potential of small gallbladder polyps--systematic review of evidence. Surgeon 12:221-226 (PMID: 24502936)

[3] Albores-Saavedra J, Chable-Montero F, Gonzalez-Romo MA, et al (2012) denomas of the gallbladder. Morphologic features, expression of gastric and intestinal mucins, and incidence of high-grade dysplasia/carcinoma in situ and invasive carcinoma. Hum Pathol 43:1506-1513 (PMID: 22386521)

[4] Chlumska A, Waloschek T, Mukensnabi P, et al (2015) Pyloric gland adenoma: a histologic, immunohistochemical and molecular genetic study of 23 cases. Cesk Patol 51:137-143. (PMID: 26421956)

[5] Trivedi V, Gumaste VV, Liu S, et al (2008) Gallbladder cancer: adenoma-carcinoma or dysplasia-carcinoma sequence ?. Gastroenterol Hepatol 4(10):735-7 (PMID: 21960895)

[6] Yang G, Qin H, Raza A, et al (2016) Pyloric gland adenoma of gallbladder - reports of two cases and a brief review of literature. J Gastrointest Oncol 7Suppl 1:S81-S87. (PMID: 27034818)

[7] Grand D, Horton KM, Fishman EK (2004) CT of the Gallbladder: Spectrum of Disease. AJR Am J Roentgenol 183:163–170 (PMID: 15208132)

[8] Mellnick VM, Menias CO, Sandrasegaran K, et al (2015) Polypoid lesions of the gallbladder: disease spectrum with pathologic correlation. Radiographics 35:387-399 (PMID: 25763724)

[9] Revzin MV, Scoutt L, Smitaman E, et al (2015) The gallbladder: uncommon gallbladder conditions and unusual presentations of the common gallbladder pathological processes. Abdom Imaging 40:385-399 (PMID: 25063238)

[10] Catalano OA, Sahani DV, Kalva SP, et al (2008) MR imaging of the gallbladder: a pictorial essay. Radiographics 28:135-155 (PMID: 18203935)

[11] Jin W, Zhang C, He X, et al (2013) Differences between images of large adenoma and protruding type of gallbladder carcinoma. Oncol Lett 5:1629-1632 (PMID: 23760294)

[12] Park KW, Kim SH, Choi SH, et al (2010) Differentiation of nonneoplastic and neoplastic gallbladder polyps 1 cm or bigger with multidetector row computed tomography. J Comput Assist Tomogr 34:135-139. (PMID: 20118736)

[13] Yoshioka M, Watanabe G, Uchinami H, et al (2013) Diffusion-weighted MRI for differential diagnosis in gallbladder lesions with special reference to ADC cut-off values. Hepatogastroenterology 60:692-698. (PMID: 24046830)

[14] Irie H, Kamochi N, Nojiri J, et al (2011) High b-value diffusion-weighted MRI in differentiation between benign and malignant polypoid gallbladder lesions. Acta Radiol 52:236-240 (PMID: 21498356)

[15] Lee NK, Kim S, Kim TU, et al (2014) Diffusion-weighted MRI for differentiation of benign from malignant lesions in the gallbladder. Clin Radiol 69:e78-85 (PMID: 24290779)

Case information

URL:	https://www.eurorad.org/case/14309
DOI:	10.1594/EURORAD/CASE.14309
ISSN:	1563-4086

License

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Figure 1

Ultrasound

Sonography showed a large (maximum diameter 3.6 cm) non-mobile homogeneous intraluminal mass (arrowheads), approximately isoechoic with the liver, overlying the continuous, non-thickened gallbladder wall (thin arrows).

The gallbladder intraluminal mass (arrowheads) was seen overlying the continuous, non-thickened gallbladder wall (thin arrows), showed lobulated margins and appeared approximately isoechoic with the liver.

Figure 2

Unenhanced and post-contrast multidetector CT

The intraluminal gallbladder mass (arrowhead) overlying the non-thickened wall (thin arrow) showed solid attenuation values (28-30 Hounsfield units) on unenhanced scans. Note fatty liver, peripancreatic oedema (*).

Post-contrast images showed moderately vascularised gallbladder intraluminal mass (arrowheads) with vascular pedicle in the arterial-dominant (b,c) phase. Note continuous, normally enhancing gallbladder wall (thin arrows), peripancreatic oedema (*).

Moderately vascularised intraluminal mass (arrowheads) with vascular pedicle in the arterial-dominant (b,c) phase. Note normal thickness and enhancement of gallbladder wall (thin arrows), duodenal lipoma (thick arrow)

Portal venous phase images (d,e) showed moderately enhancing intraluminal gallbladder mass (arrowheads) overlying the normal gallbladder wall (thin arrows). Note normal pancreatic enhancement, peripancreatic oedema (*).

Figure 3

MRI - T2-, Diffusion-weighted and MR cholangiopancreatography images

T2-weighted images (a-b, fat-suppressed c) confirmed intraluminal gallbladder mass (arrowheads) with low signal intensity, overlying the thin, continuous gallbladder wall (thin arrows).

The intraluminal gallbladder mass (arrowheads) did not show diffusion restriction at b 800 (d) with corresponding apparent diffusion coefficient (ADC) value 2.1x10-3 mm2/s (e).

MR-cholangiopancreatography images showed small filling defects (arrows) in the non-dilated common bile duct, consistent with sludge, blood clots or fragments of the gallbladder mass (arrowheads).

Figure 4

MRI - Precontrast and dynamic enhanced T1-weighted images

The intraluminal gallbladder mass (arrowhead) showed low-to-intermediate precontrast T1 signal intensity.

The intraluminal gallbladder mass was moderately and homogeneously enhanced in the arterial phase (b, c with subtraction) after intravenous gadolinium contrast (gadobutrol).

Portal venous (d,e) and equilibrium phase (f) showed persistent moderate and homogeneous enhancement of the gallbladder mass (arrowheads); normally enhancing, thin and continuous gallbaldder wall (thin arrows).

Portal venous (d,e) showed persistent moderate and homogeneous enhancement of the gallbladder mass (arrowheads); normally enhancing, thin and continuous gallbaldder wall (thin arrows), nonenhanced duodenal lipoma (thick arrow).