Mucin-producing Cystic Hepatobiliary Neoplasms: Updated Nomenclature and Clinical, Pathologic, and Imaging Features

Practical approach to diagnose and manage benign liver masses

Benign liver lesions are among the most commonly diagnosed abnormalities in liver imaging. They are often discovered incidentally during routine examinations or imaging conducted for unrelated reasons. These can be solid lesions, such as hemangiomas, focal nodular hyperplasia, hepatic adenomas, or cystic lesions. Recent advancements in MRI technology, particularly with hepatocyte-specific contrast agents, have enhanced the characterization of these lesions, reducing the reliance on invasive tissue sampling. Nevertheless, tissue sampling retains a crucial role in the evaluation of indeterminate lesions or those with malignant potential. While most benign liver lesions are asymptomatic, some can become symptomatic, causing discomfort, pain, or bleeding, particularly if the lesion is large. A deep understanding of the molecular underpinnings of the lesions is crucial for tailoring patient management strategies, particularly in distinguishing lesions that require surgical intervention from those that can be monitored. For instance, the molecular subclassification of hepatic adenomas has provided mechanistic insights and identified certain subtypes that are at higher risk of malignancy. Most benign liver lesions can be safely monitored; however, in patients with cirrhosis or a known primary malignancy, a high index of suspicion for cancer is required. It is crucial to carefully evaluate any liver lesion identified in these patients to ensure that indeterminate lesions are not overlooked. Effective management of benign liver lesions involves a multidisciplinary team, including hepatologists, surgeons, and radiologists, ensuring a comprehensive and individualized approach to patient care. This review outlines the clinical presentation of common benign liver lesions, providing a diagnostic and management framework. Emphasis is placed on a personalized approach to minimize patient distress and optimize outcomes by leveraging imaging advancements and multidisciplinary collaboration.

Successful Surgical Management of Giant Mucinous Cystic Neoplasm of Liver (MCN-L) Presenting With Peritoneal Rupture and Biliary Prolapse: Case Report and Review of Literature

Mucinous cystic neoplasms of liver (MCN-L) are generally considered benign indolent cystic liver lesions, not associated with significant clinical symptoms in majority of patients. However, rarely these benign-appearing lesions may have a complicated clinical course, presenting with jaundice, acute abdomen, or malignant transformation. We report one such rare clinical presentation of MCN-L presenting with obstructive jaundice and abdominal pain due to prolapse of cystic component in biliary system and peritoneal rupture occurring simultaneously. Despite the complex nature of presentation, it was successfully managed surgically with normal follow-up imaging.

To identify important MRI features to differentiate hepatic mucinous cystic neoplasms from septated hepatic cysts based on random forest

OBJECTIVE

To identify important MRI features to differentiate hepatic mucinous cystic neoplasms (MCN) from septated hepatic cysts (HC) using random forest and compared with logistic regression algorithm.

METHODS

Pathologically diagnosed hepatic cysts and hepatic MCNs with pre-operative contrast-enhanced MRI in our hospital from 2010 to 2023 were collected and only septated lesions on enhanced MRI were enrolled. A total of 21 septated HC and 18 MCNs were included in this study. Eighteen MRI features were analyzed and top important features were identified based on random forest (RF) algorithm. The results were evaluated by the prediction performance of a RF model combining the important features and compared with the performance of the logistic regression (LR) algorithm. Finally, for each identified feature, diagnostic probability, sensitivity, and specificity were calculated and compared.

RESULTS

Four variables, i.e., the septation arising from wall without indentation, multiseptate, intracapsular cyst sign, and solitary lesion were extracted as top important features with significance for MCNs by the random forest algorithm. The RF model using these variables had an AUC of 0.982 (0.95CI, 0.950-1.000), compared with the LR model based on two identified features with AUC of 0.931 (0.95CI, 0.846-1.000), p = 0.202. Among the four important features, multiseptate had the highest specificity (95.2%) and good sensitivity (72.2%, lower than the septation from wall without indentation, 94.4%) to diagnose MCNs.

CONCLUSION

Four out of 18 MRI features were extracted as reliably important factors to differ hepatic MCNs from septated HC. The combination of these four features in a RF model could achieve satisfactory diagnostic efficacy.

ACG Clinical Guideline: Focal Liver Lesions

Focal liver lesions (FLLs) have become an increasingly common finding on abdominal imaging, especially asymptomatic and incidental liver lesions. Gastroenterologists and hepatologists often see these patients in consultation and make recommendations for management of multiple types of liver lesions, including hepatocellular adenoma, focal nodular hyperplasia, hemangioma, and hepatic cystic lesions including polycystic liver disease. Malignancy is important to consider in the differential diagnosis of FLLs, and healthcare providers must be familiar with the diagnosis and management of FLLs. This American College of Gastroenterology practice guideline uses the best evidence available to make diagnosis and management recommendations for the most common FLLs.

Peribiliary cysts: uncommon mimickers of hepatic and biliary cystic lesions

Peribiliary cysts (PC) are dilatations of the extramural peribiliary glands, with a very characteristic imaging pattern in the contexts of hepatobiliary diseases, idiopathic portal hypertension, adult-type polycystic disease of the liver and kidneys, solitary nonparasitic cysts, and systemic infections. The clinical relevance of PC is related to the fact that their presence may indicate underlying pathologies (such as those mentioned above) and may be considered as a potential marker of liver disease progression. Although imaging findings are quite characteristic, recognizing their main differential diagnoses, including malignancies, can be challenging but are essential to avoiding diagnostic errors.

Imaging features and management of focal liver lesions

Notably, the number of incidentally detected focal liver lesions (FLLs) has increased dramatically in recent years due to the increased use of radiological imaging. The diagnosis of FLLs can be made through a well-documented medical history, physical examination, laboratory tests, and appropriate imaging methods. Although benign FLLs are more common than malignant ones in adults, even in patients with primary malignancy, accurate diagnosis of incidental FLLs is of utmost clinical significance. In clinical practice, FLLs are frequently evaluated non-invasively using ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). Although US is a cost-effective and widely used imaging method, its diagnostic specificity and sensitivity for FLL characterization are limited. FLLs are primarily characterized by obtaining enhancement patterns through dynamic contrast-enhanced CT and MRI. MRI is a problem-solving method with high specificity and sensitivity, commonly used for the evaluation of FLLs that cannot be characterized by US or CT. Recent technical advancements in MRI, along with the use of hepatobiliary-specific MRI contrast agents, have significantly improved the success of FLL characterization and reduced unnecessary biopsies. The American College of Radiology (ACR) appropriateness criteria are evidence-based recommendations intended to assist clinicians in selecting the optimal imaging or treatment option for their patients. ACR Appropriateness Criteria Liver Lesion-Initial Characterization guideline provides recommendations for the imaging methods that should be used for the characterization of incidentally detected FLLs in various clinical scenarios. The American College of Gastroenterology (ACG) Clinical Guideline offers evidence-based recommendations for both the diagnosis and management of FLL. American Association for the Study of Liver Diseases (AASLD) Practice Guidance provides an approach to the diagnosis and management of patients with hepatocellular carcinoma. In this article, FLLs are reviewed with a comprehensive analysis of ACR Appropriateness Criteria, ACG Clinical Guideline, AASLD Practice Guidance, and current medical literature from peer-reviewed journals. The article includes a discussion of imaging methods used for the assessment of FLL, current recommended imaging techniques, innovations in liver imaging, contrast agents, imaging features of common nonmetastatic benign and malignant FLL, as well as current management recommendations.

Intraductal papillary neoplasms of the bile ducts-what can be seen with ultrasound?

Intraductal papillary neoplasm of the bile ducts is a rare tumor. Characteristic features include bile duct dilatation, cystic lesions with communication to the bile ducts, and intraluminal solid nodules arising from the bile duct wall. As in pancreatic intraductal papillary mucinous neoplasia, intestinal, pancreaticobiliary, gastric, and oncocytic types are described. Intraductal papillary neoplasm of the bile ducts has a high potential for malignancy, and patients should be surgically resected when possible. In this review, the complex imaging diagnosis is presented. The main focus is on contrast-enhanced ultrasound, an established method for many other indications whose potential on the biliary system should be better exploited. In the present article, typical contrast-enhanced ultrasound findings in intraductal papillary neoplasm of the bile ducts are demonstrated.

Management of Mucinous Cystic Neoplasms of the Liver

BACKGROUND

Mucinous cystic neoplasms of the liver (MCN-L) including biliary cystadenomas (BCA) and biliary cystadenocarcinomas (BCAC) are rare cystic lesions that comprise less than 5% of all liver cysts and affect only a small subset of individuals. We herein review the current evidence regarding the clinical presentation, imaging characteristics, tumor markers, pathological findings, clinical management, and prognosis of MCN-L.

METHODS

A comprehensive review of the literature was performed using MEDLINE/Pubmed and Web of Science databases. In PubMed, the terms "biliary cystadenoma," "biliary cystadenocarcinoma," and "non parasitic hepatic cysts" were queried to identify the most recent data on MCN-L.

RESULTS

US imaging, CT, and MRI, as well as consideration of clinicopathological features, are required to appropriately characterize and diagnose hepatic cystic tumors. BCA are premalignant lesions and cannot be reliably differentiated from BCAC based on imaging alone. As such, both types of lesions should be treated with margin-negative surgical resection. Following surgical resection, recurrence is fairly low among patients with BCA and BCAC. Despite having worse long-term outcomes than BCA, the prognosis following surgical resection of BCAC still remains more favorable than other primary malignant liver tumors.

CONCLUSION

MCN-L are rare cystic liver tumors that include BCA and BCAC, which can be difficult to differentiate based on imaging alone. Surgical resection remains the mainstay of management for MCN-L with recurrence being generally uncommon. Future multi-institutional studies are still required to better understand the biology behind BCA and BCAC to improve the care of patients with MCN-L.

Imaging of Hepatobiliary Cancer

The liver and biliary tree are common sites of primary and secondary malignancies. MRI followed by CT is the mainstay for the imaging characterization of these malignancies with the dynamically acquired contrast enhanced phases being the most important for diagnosis. The liver imaging reporting and data system classification provides a useful framework for reporting lesions in patents with underlying cirrhosis or who are at high risk for developing hepatocellular carcinoma. Detection of metastases is improved with the use of liver specific MRI contrast agents and diffusion weighted sequences. Aside from hepatocellular carcinoma, which is often diagnosed noninvasively, other primary hepatobiliary tumors may require biopsy for definite diagnosis, especially when presenting with nonclassic imaging findings. In this review, we examine the imaging findings of common and less common hepatobiliary tumors.

The multidisciplinary management of cholangiocarcinoma

Cholangiocarcinoma is a lethal malignancy of the biliary epithelium that can arise anywhere along the biliary tract. Surgical resection confers the greatest likelihood of long-term survivability. However, its insidious onset, difficult diagnostics, and resultant advanced presentation render the majority of patients unresectable, highlighting the importance of early detection with novel biomarkers. Developing liver-directed therapies and emerging targeted therapeutics may offer improved survivability for patients with unresectable or advanced disease. In this article, the authors review the current multidisciplinary standards of care in resectable and unresectable cholangiocarcinoma, with an emphasis on novel biomarkers for early detection and nonsurgical locoregional therapy options.

EASL Clinical Practice Guidelines on the management of cystic liver diseases

The advent of enhanced radiological imaging techniques has facilitated the diagnosis of cystic liver lesions. Concomitantly, the evidence base supporting the management of these diseases has matured over the last decades. As a result, comprehensive clinical guidance on the subject matter is warranted. These Clinical Practice Guidelines cover the diagnosis and management of hepatic cysts, mucinous cystic neoplasms of the liver, biliary hamartomas, polycystic liver disease, Caroli disease, Caroli syndrome, biliary hamartomas and peribiliary cysts. On the basis of in-depth review of the relevant literature we provide recommendations to navigate clinical dilemmas followed by supporting text. The recommendations are graded according to the Oxford Centre for Evidence-Based Medicine system and categorised as 'weak' or 'strong'. We aim to provide the best available evidence to aid the clinical decision-making process in the management of patients with cystic liver disease.