CASE 11575 Published on 24.02.2014

Unilocular mucinous cystoadenoma of the porta hepatis

Section

Abdominal imaging

Case Type

Clinical Cases

Authors

Fabiano S, Funel V, Ciancarella P, Di Giuliano F, Bindi A, Simonetti G

Policlinico Tor Vergata,
Viale Oxford 81,
00133 Roma (RM), Italy

Patient

54 years, female

Categories

Area of Interest Biliary Tract / Gallbladder ; Imaging Technique Ultrasound, Ultrasound-Colour Doppler, MR

Procedure Diagnostic procedure ; Special Focus Cysts ;

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Clinical History

A 54-year-old post-menopausal woman was referred to our institution to perform a hepatobiliary MRI for upper abdominal pain and dyspepsia, occurred in the past year.
She had previously undergone a US examination showing a round hypoechoic liver lesion of unclear diagnosis. She reported no relevant medical history.

Imaging Findings

US presented a 1cm hypoechoic unilocular cyst-like lesion with thin walls, without internal septa, mural nodules or papillary projections, localized in the porta hepatis and showing apparent communication with the common hepatic duct. Doppler evaluation did not demonstrate significant vascularization.
MRI images confirmed the presence of a lesion right near the confluence of the right and left hepatic duct. It had a very high signal intensity on T1-weighted images and mild hyperintensity on T2-weighted images; fat-sat images excluded the presence of adipous content. Morphological characteristics of the lesion were similar to US finding with round shape and homogeneous signal.
The lesion did not show significant contrast enhancement with a lower signal hyperintensity due to the rescaling phenomenon.
Surgical excision was performed and histological diagnosis revealed a well-defined mucinous cystic lesion communicating with the left hepatic duct, composed by a single-layered columnar epithelium with mesenchimal ovarian-like stroma.

Discussion

Biliary cystoadenomas represent the benign type of biliary cystic tumours and were recently classified as mucinous cystic neoplasms in the W.H.O. classification of the biliary tumours [1]. They are uncommon cystic neoplasms that occur most frequently within the liver, while are less common in the extra-hepatic biliary tree or in the gallbladder (< 10%) [2].
Histological analysis typically shows multiple loculations but in rare cases they are unilocular; the latter are more frequently intra-hepatic. The cyst may contain serous, mucinous, bilious, haemorrhagic or mixed fluid. They show ovarian-like stroma in the cyst wall [3-4].
The clinical presentation is variable and nonspecific, depending on size and location of the lesion: abdominal pain, nausea, vomiting, upper quadrant palpable mass, jaundice. Occasionally cystoadenomas may be incidentally discovered during abdominal imaging studies. They are more frequent in middle-aged women.
Although biliary cystoadenomas are benign tumours, they can progress to cystoadenocarcinomas and may recur after surgical excision [5]. Furthermore cystic lesions of the liver comprise a broad spectrum of pathological entities, ranging from developmental lesions (simple cysts, biliary hamartomatosis, Caroli disease) and inflammatory lesions (abscesses, hydatid cysts) to neoplastic lesions (cystic hepatocellular carcinomas and liver metastases) and rare diseases (intra-hepatic haematomas and bilomas) [6-7].
Abdominal radiographs can show hepatomegaly and wall calcifications. US and CT show unilocular or multilocular cyst; the transmission and the attenuation depend on the fluid content (serous, bilious, mucinous or proteinaceous); thin mural nodes and papillary projections may be present. Signs of haemorrhage and calcifications are rarely visible. Septa and soft tissue components of the walls may enhance after the administration of contrast media [3].
Also MRI signal can vary with the cystic content, with mucinous cysts showing typical hyperintensity on T1-weighted images and mild hyperintensity on T2-weighted images. Moderate enhancement may be present.
Cholangiography is helpful in case of duct dilatation or obstruction and it can demonstrate a communication of the cystadenoma with the biliary tree. The latter can also be demonstrated in the hepatobiliary phase of an MRI using a hepatocyte-specific contrast agent [8].
The presence of irregular wall thickening, thick solid nodules and septa, intense enhancement and coarse calcification are suspicious of malignant transformation.
If a benign disease is ascertained, observation and/or follow-up examinations can be recommended. However, image features are often inconclusive and require surgical excision to confirm the diagnosis.

Differential Diagnosis List

Unilocular mucinous cystoadenoma communicating with the left hepatic duct.

Hepatic echinococcal cyst

Endometriotic cyst

Hepatic abscess

Metastasis from melanoma

Intraductal papillary neoplasm of the bile duct

Focal biliary dilatation

Final Diagnosis

Unilocular mucinous cystoadenoma communicating with the left hepatic duct.

References

[1] Bosman FT, Carneiro F, Hurban RH, Theise ND, eds (2010) WHO classification of tumors digestive system. Lyon, France: International Agency for Research on Cancer Press 222-224, 236-238

[2] Lim JH, Zen Y, Jang KT, Kim YK, Nakanuma Y (2011) Cyst-forming intraductal papillary neoplasm of the bile ducts: description of imaging and pathologic aspects. AJR 197:5, 1111-1120 (PMID: 22021503)

[3] Levy AD, Murakata LA, Abbott RM, Rohrmann CA Jr (2002) From the archives of the AFIP. Benign tumors and tumorlike lesions of the gallbladder and extrahepatic bile ducts: radiologic-pathologic correlation. Armed Forces Institute of Pathology. Radiographics Mar-Apr;22(2):387-413 (PMID: 11896229)

[4] Buetow PC, Buck JL, Pantongrag-Brown L, et al (1995) Biliary cystadenoma and cystadenocarcinoma: clinical-imaging-pathologic correlations with emphasis on the importance of ovarian stroma. Radiology 196:805–810 (PMID: 7644647)

[5] Ishak KG, Willis GW, Cummins SD, Bullock AA (1977) Biliary cystadenoma and cystadenocarcinoma: report of 14 cases and review of the literature. Cancer Jan 39(1):322-38 (PMID: 318915)

[6] Mortelé KJ, Ros PR (2001) Cystic focal liver lesions in the adult: differential CT and MR imaging features. RadioGraphics 21:895-910 (PMID: 11452064)

[7] Singh Y, Winick AB, Tabbara SO (1997) Multiloculated cystic liver lesions: radiologic-pathologic differential diagnosis. RadioGraphics 17:219–224 (PMID: 9017811)

[8] Billington PD, Prescott RJ, Lapsia R (2012) Diagnosis of a biliary cystadenoma demonstrating communication with the biliary system by MRI using a hepatocyte-specific contrast agent. Br J Radiol 85(1010):e35-6 (PMID: 22308224)

Case information

URL:	https://www.eurorad.org/case/11575
DOI:	10.1594/EURORAD/CASE.11575
ISSN:	1563-4086

Figure 1

Ultrasonography

45° oblique scan showing the porta hepatis. A round hypoechoic cyst-like lesion is visible above the portal vein and the common hepatic duct.

45° oblique scan detailing the cyst-like lesion: it appears unilocular and it shows thin walls, without internal septa, mural nodules or papillary projections.

45° oblique scan showing an apparent communication with the common hepatic duct and the maximum diameters of the lesion (10.5 x 11.4 mm).

Colour-Doppler sonogram of the same lesion showing the absence of proper vascularization.

Figure 2

Contrast-enhanced MRI of the abdomen

T1-weighted GRE sequence in the axial plane showing a round-shaped lesion with a very high signal intensity near the hepatic hilum. The maximum diameter measures 15.6 mm.

T2-weighted TSE sequence in the axial plane presenting the same lesion with mild homogeneous hyperintensity and thin walls. No mural node or papillary projection is visible.

T2-weighted SPIR sequence in the axial plane revealing the high signal intensity of the lesion, suggesting fluid content.

Fast GRE \"THRIVE\" sequence in the axial plane excluding the presence of adipous content within the lesion.

Fast GRE \"THRIVE\" sequence in the axial plane acquired in the arterial phase. The lesion appears less hyperintense for the \"rescaling\" phenomenon.

Fast GRE \"THRIVE\" sequence in the axial plane acquired in the portal-venous phase. The lesion appears even less hyperintense.

Fast GRE \"THRIVE\" sequence in the axial plane acquired in the equilibrium phase.

Ballanced sequence in the coronal plane. Here the lesion appears in the hepatic hilum (arrow).

Fast GRE \"THRIVE\" sequence in the portal-venous phase. Multiplanar reconstruction shows the lesion. The arrow indicate the confluence between the left and the right hepatic ducts in the common hepatic duct.