Growth of Focal Nodular Hyperplasia is Not a Reason for Surgical Intervention, but Patients Should be Referred to a Tertiary Referral Centre

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.

Focal Nodular Hyperplasia: A Comprehensive Review with a Particular Focus on Pathogenesis and Complications

Focal nodular hyperplasia is a benign tumor of the liver that is often found incidentally with imaging. The purpose of this review is to discuss the pathophysiology, rare complications that can occur due to these lesions, and management options. A literature review was performed on clinical trials and case reports involving focal nodular hyperplasia complications and management of these, as well as the proposed pathogenesis underlying these tumors. Although exposure to oral contraceptive pills and endogenous hormones have been thought to play a role in the development of these lesions, this has not been proven. Most recently, they are thought to arise as a consequence of a vascular anomaly causing alterations in the expression of angiopoietin genes. Complications are rare, but previous cases have reported associated pain, rupture and compression of nearby structures (hepatic vein, stomach, biliary system). Resection of focal nodular hyperplasia is not usually recommended. However, if there is associated pain with no other identifiable cause or presence of a large or growing lesion with risk of causing a complication, then surgical resection, radiofrequency ablation or arterial embolization should be considered.

Pedunculated Focal Nodular Hyperplasia: When in Doubt, Should We Cut It Out?

Focal nodular hyperplasia (FNH) is the second most common benign hepatic tumor and can rarely present as an exophytic solitary mass attached to the liver by a stalk. Most FNH cases are usually detected as incidental findings during surgery, imaging or physical examination and have a high female predominance. However, the pedunculated forms of FNH are particularly rare and commonly associated with severe complications and diagnostic challenges. Hence, our study aims to provide a comprehensive summary of the available data on the pedunculated FNH cases among adults and children. Furthermore, we will highlight the role of different therapeutic options in treating this clinical entity. The use of imaging techniques is considered a significant addition to the diagnostic toolbox. Regarding the optimal treatment strategy, the main indications for surgery were the presence of symptoms, diagnostic uncertainty and increased risk of complications, based on the current literature. Herein, we also propose a management algorithm for patients with suspected FNH lesions. Therefore, a high index of suspicion and awareness of this pathology and its life-threatening complications, as an uncommon etiology of acute abdomen, is of utmost importance in order to achieve better clinical outcomes.

Suspected focal nodular hyperplasia in male adults: 10-year experience from a large liver centre

PURPOSE

Focal nodular hyperplasia (FNH) is commonly found in females of reproductive age. In males, the diagnosis is made more cautiously due to its lower incidence and higher incidence of hepatocellular carcinoma, which can have overlapping imaging features. Follow-up or biopsy is sometimes required. This retrospective study aims to assess management of suspected FNH in male adult patients at our institution over a 10-year period.

METHODS

Male adults (≥ 18 years) suspected of having FNH from January 2010-June 2020 were identified using a departmental radiology information system search. Data was collected from radiology reports and patient pathway manager.

RESULTS

Of 342 patients with suspected FNH, 62 were male (18.1%; F:M of 4.5:1). We only included patients investigated and followed up by MRI, total of 57 patients. Median age was 40 years (range 18-74 years). Background liver disease present in 21/57 (36.8%), majority with hepatic steatosis. Average number of lesions per patient 1.7. 22/57 (38.6%) had at least one MRI follow-up using liver-specific contrast with 7 lesions demonstrating variation in size (range growth: -3.27 mm/year to + 4 mm/year). In 7 cases, MRI was not definitive; 6 required biopsy and 1 resection. Only 2/7 demonstrated malignancy. Of the total 57 patients, 6 have deceased and none due to a misdiagnosed or mismanaged hepatic lesion.

CONCLUSION

FNH is relatively uncommon in males, however, our data suggests that lesions with typical MRI characteristics do not require follow-up and diagnosis can be made confidently, similar to females. Any atypical features should prompt a biopsy.

Imaging strategy for focal nodular hyperplasia in children: long-term experience from two specialist European centres

BACKGROUND

Focal nodular hyperplasia (FNH) in children is a rare but benign tumour, which must be differentiated from malignant entities to avoid unnecessary treatment, leading to potential morbidity.

OBJECTIVES

To provide data on imaging findings of these lesions with a suggested algorithm for diagnosis, sampling and follow-up.

MATERIALS AND METHODS

This retrospective review evaluated imaging of all patients diagnosed with FNH in two tertiary referral centres in Europe between 1975 and 2018.

RESULTS

One hundred and four patients with 137 tumours were reviewed. The mean age at presentation was 8.2 years. The median tumour size was 5 cm (range: 0.3-29 cm). Multiple lesions were seen in 16.3% of patients. The male-to-female ratio was 1:2.

CONCLUSION

FNH with typical features on imaging can be safely followed up once the diagnosis has been established. The use of contrast-enhanced ultrasound and magnetic resonance imaging allows accurate characterisation in most cases. Histological sampling is only advised when there is diagnostic doubt. Atypical arterial enhancement of FNH should prompt the search for a congenital portosystemic shunt.

Benign liver tumours: understanding molecular physiology to adapt clinical management

Improvements in understanding the pathophysiology of the different benign liver nodules have refined their nosological classification. New criteria have been identified using imaging, histology and molecular analyses for a precise diagnosis of these tumours. Improvement in the classification of liver tumours provides a more accurate prediction of disease progression and has modified patient management. Haemangioma and focal nodular hyperplasia, the most common benign liver tumours that develop in the absence of chronic liver disease, are usually easy to diagnose on imaging and do not require specific treatment. However, hepatocellular adenomas and cirrhotic macronodules can be difficult to discriminate from hepatocellular carcinoma. The molecular subtyping of hepatocellular adenomas in five major subgroups defined by HNF1A inactivation, β-catenin mutation in exon 3 or exon 7/8, and activation of inflammatory or Hedgehog pathways helps to identify the tumours at risk of malignant transformation or bleeding. New clinical, biological and molecular tools have gradually been included in diagnostic and treatment algorithms to classify benign liver tumours and improve patient management. This Review aims to explain the main pathogenic mechanisms of benign liver tumours and how this knowledge could influence clinical practice.

Focal Nodular Hyperplasia and Focal Nodular Hyperplasia-like Lesions

Focal nodular hyperplasia (FNH) is a benign lesion occurring in a background of normal liver. FNH is seen most commonly in young women and can often be accurately diagnosed at imaging, including CT, MRI, or contrast-enhanced US. In the normal liver, FNH frequently must be differentiated from hepatocellular adenoma, which although benign, is managed differently because of the risks of hemorrhage and malignant transformation. When lesions that are histologically identical to FNH occur in a background of abnormal liver, they are termed FNH-like lesions. These lesions can be a source of diagnostic confusion and must be differentiated from malignancies. Radiologists' familiarity with the imaging appearance of FNH-like lesions and knowledge of the conditions that predispose a patient to their formation are critical to minimizing the risks of unnecessary intervention for these lesions, which are rarely symptomatic and carry no risk for malignant transformation. FNH is thought to form secondary to an underlying vascular disturbance, a theory supported by the predilection for formation of FNH-like lesions in patients with a variety of hepatic vascular abnormalities. These include abnormalities of hepatic outflow such as Budd-Chiari syndrome, abnormalities of hepatic inflow such as congenital absence of the portal vein, and hepatic microvascular disturbances, such as those that occur after exposure to certain chemotherapeutic agents. Familiarity with the imaging appearances of these varied conditions and knowledge of their association with formation of FNH-like lesions allow radiologists to identify with confidence these benign lesions that require no intervention. Online supplemental material is available for this article. ^©RSNA, 2022.

Long-term outcomes of transarterial embolization with lipiodol-bleomycin emulsion plus polyvinyl alcohol particles versus the particles alone for large symptomatic focal nodular hyperplasia: a propensity score-matched analysis

OBJECTIVES

To compare the efficacy of transarterial embolization (TAE) with polyvinyl alcohol (PVA) particles alone and lipiodol-bleomycin emulsion (LBE) plus PVA particles for patients with unresectable large symptomatic focal nodular hyperplasia (FNH).

METHODS

We performed a retrospective analysis of patients who underwent TAE either with PVA particles alone (group A, n = 46) or LBE plus PVA particles (group B, n = 35) for large (≥ 7 cm) symptomatic FNH between January 2002 and February 2019. Propensity score matching (PSM) (1:1) was performed to adjust for potential baseline confounders. Technical success, adverse events (AEs), symptom relief, and changes in the lesion size after TAE were evaluated. Statistical analysis included Wilcoxon rank sum test and χ² test.

RESULTS

After PSM, no significant differences in baseline characteristics were found between the groups (31 in group A and 31 in group B, with a mean age of 31 years). Technical success was achieved in all patients (100%), without major AEs in both groups. Complete resolution of the abdominal symptoms was reported in 77.4% in group A and 100% in group B (p = 0.037) during a mean follow-up period of 72 months; complete resolution (CR) of the FNH rate was significantly higher in group B than in group A (93.6% vs. 67.7%; p = 0.019).

CONCLUSION

Compared with the use PVA particles alone, TAE with LBE plus PVA particles in the treatment of patients with large symptomatic FNH had a significantly higher rates of CR of the FNH and complete relief of the symptoms.

KEY POINTS

• Transarterial embolization (TAE) with lipiodol-bleomycin emulsion (LBE) plus PVA particles for the large symptomatic FNH yielded better results than with PVA particles alone, in terms of complete resolution of FNH lesions (93.6% vs 67.7%) and complete relief of the abdominal symptoms (100% vs 77.4%) during a mean follow-up period of 72 months (38-170 months). • No major complications were recorded in both groups, and no significant difference in the incidence of postembolization syndrome were observed between the two groups.

Focal nodular hyperplasia mimicking hepatocellular adenoma and carcinoma in two cases

Focal nodular hyperplasia (FNH) is a solid benign tumor of the liver, predominantly in young women. A correct diagnosis of FNH is essential for making appropriate clinical decisions and avoiding unnecessary liver resection. Herein, we reported that two male cases with FNH, who initially presented with persistent abdominal discomfort, were misdiagnosed with hepatocellular adenoma (HCA) and hepatocellular carcinoma (HCC) on contrast-enhanced magnetic resonance imaging and computed tomography scans, respectively. After surgery, a histological diagnosis of FNH was finally established. In this paper, we also reviewed the knowledge regarding diagnosis and differential diagnosis of FNH on imaging examinations, which are helpful for avoiding misdiagnoses and guiding clinical interventions.

Focal nodular hyperplasia in a 14-year-old child: A case report

BACKGROUND

Focal nodular hyperplasia (FNH) is a benign rare liver neoplasm in children and includes only 2% of all pediatric liver tumors. Here we reported the case of a 14-year-old girl with vague flank pain who was managed conservatively.

CASE PRESENTATION

Our case is a 14-year-old child (female), with a 5 cm diameter lesion in the right lobe of the liver in CT scan, and histologic findings compatible with FNH. A solid mass lobulated contour, intense enhancement with a hypodense central area, possibly indicative of central scar, was seen. Despite her mild flank pain we did not insist on surgical resection and managed her conservatively. Her pain resolved 2 weeks later and an imaging follow-up with ultrasound 6 months later showed no increase in size or numbers.

CONCLUSION

FNH is an uncommon mass lesion in children. Our patient had mild symptomatic severity, and several guidelines recommend surgical treatment in this condition, but our team performed conservative and medical treatment for her and got the desired result. Therefore, the combination of these factors raises the importance of introducing the case. According to FNH's nature, stability, complications, and evaluation of pain are essential to avoid unnecessary surgeries.

Robotic resection of liver focal nodal hyperplasia guided by indocyanine green fluorescence imaging: A preliminary analysis of 23 cases

BACKGROUND

Focal nodal hyperplasia (FNH) is a common benign tumor of the liver. It occurs mostly in people aged 40-50 years and 90% of the patients are female. FNH can be cured by local resection. How to locate and judge the tumor boundary in real time is often a challenge for surgeons.

AIM

To summarize the technique and feasibility of robotic resection of FNH guided by indocyanine green (ICG) fluorescence imaging.

METHODS

The demographics and perioperative outcomes of a consecutive series of patients who underwent robotic resection of liver FNH guided by ICG fluorescence imaging between May 1, 2018 and September 30, 2019 were retrospectively analyzed. ICG was injected through the median elbow vein in all the patients at a dose of 0.25 mg/kg 48 h before the operation. During the operation, the position of FNH in the liver was located in the fluorescence mode of the Da Vinci Si robot operating system and the tumor boundary was determined during the resection.

RESULTS

Among the 23 patients, there were 11 males and 12 females, with a mean age of 30.5 ± 9.3 years. Twenty-two cases completed robotic resection, while one (4.3%) case converted to open surgery. In the robotic surgery group, the operation time was 35-340 min with a median of 120 min, the intraoperative bleeding was 10-800 mL with a median of 50 mL, and the postoperative hospital stay was 1-7 d with a median of 4 d. Biliary fistula occurred in two (8.7%) patients after robotic operation and they both recovered after conservative treatment. One (4.3%) patient received blood transfusion and there was no death in this study. The postoperative hospital stay in the small tumor group was significantly shorter than that in the large tumor group (P < 0.05).

CONCLUSION

ICG fluorescence imaging can guide the surgeon to perform robotic resection of liver FNH by locating the tumor and displaying the tumor boundary in real time. It is a safe and feasible method to ensure the complete resection of the tumor.

Management of focal nodular hyperplasia of the liver: Experience of 50 pediatric patients in a tertiary center

BACKGROUND

Focal nodular hyperplasia (FNH) is a rare benign hepatic lesion in children. No management guidelines for pediatric population exist because of limited evidence.

OBJECTIVE

To review the experience of a large tertiary liver center, providing additional clinical data to help formulate management guidelines for FNH in the pediatric population.

METHODS

We analyzed data of children <18 years diagnosed with FNH from 1996 to 2018 at our hospital, detailing management and long-term clinical outcome.

RESULTS

50 patients were identified. The median age was 10 years old (range 0.75-15.5 years old). The mean diameter of FNH was 5.9 cm (±3.1 cm). 10 patients had multiple lesions. First-line management: watchful waiting with serial checks (n = 37), surgery (n = 13). Of the watchful waiting patients, 10 required eventual second-line surgery. After a median follow-up of 4.7 years (range 0.5-20 years), 46 patients were asymptomatic, with no significant difference in clinical outcome (p = 0.962) between the two first-line management approaches. Lesions demonstrated growth in 13 cases: 5 of these required second-line surgery. In these patients, there was no significant difference in clinical outcome (p = 0.188) compared to nonoperative patients. Considering all surgically treated patients, there was no significant difference between first-line and second-line surgery for clinical outcome (p = 0.846), hospital stay (p = 0.410), complications (p = 0.510) and severe complications (p = 0.385).

CONCLUSIONS

Our data support the hypothesis that watchful waiting is a safe initial approach to pediatric FNH management in patients with no major symptoms or complications. Surgery should be reserved for patients with diagnostic doubt, persistent symptoms and/or biological or significant anatomical abnormalities. FNH growth alone should not be considered as an indication for surgery.

TYPE OF STUDY

Therapeutic study.

LEVEL OF EVIDENCE

Level III.

Surgical indications for focal nodular hyperplasia of the liver: Single-center experience of 48 adult cases

Backgrounds/Aims

Focal nodular hyperplasia (FNH) is one of the most common benign tumors of the liver. There is still a lack of evidence on surgical indications for FNH. This study intended to analyze the surgical indications for FNH.

Methods

We analyzed 48 cases of FNH diagnosed after hepatic resection.

Results

Common reasons leading to surgical resection were diagnostic uncertainty (n=31), and persistent symptoms (n=8). None of our patients had a past history of contraceptive use. Percutaneous biopsy was performed in 14 patients and FNH was diagnosed in nine patients, and hepatic adenoma, hepatocellular carcinoma, plasmacytoma, angiosarcoma, and atypical hepatocellular proliferation in one patient each. Minor hepatectomy (n=37) was performed more frequently than major hepatectomy (n=11). Open hepatectomy (n=29) was performed more frequently than laparoscopic hepatectomy (n=19), but laparoscopic and minimally-invasive surgery was frequently performed during the late phase of the study period. Postoperative surgical complications occurred in two patients (4.1%).

Conclusions

FNH can be diagnosed by imaging studies, but surgical treatment may be considered in cases of diagnostic uncertainty or persistent symptoms.