Hepatocellular adenoma in the paediatric population: Molecular classification and clinical associations

Hepatocellular adenomas associated with antiepileptic drugs: A case report

Hepatocellular adenoma (HCA) represents a rare benign liver tumor occurring predominantly in females of reproductive age and taking oral contraceptives. They are associated with various conditions. We report the case of a male patient with hepatic adenomas who has an association with long-term antiepileptic drugs in treatment for seizures of Rasmussen's encephalitis without a history of anabolic steroid use or any underlying hyperestrogenism. MRI findings show multiple hepatic nodules with mainly intermediate signal on T2, intratumoral fat content without diffusion restriction, and intense enhancement in the arterial phase with and without washout in portal and equilibrium phases. The imaging characteristics of these adenomas are indicative of the HNF1 alpha-inactivated subtype. No therapeutic interventions have been performed so far. This association is rare, and few cases have been reported in the literature. This case aims to reaffirm and remind people of the association of hepatic adenomas with antiepileptic drug use and make an additional analysis of the new molecular subtypes of hepatic adenoma, described recently in the literature. Exhaustive literature research reveals few case reports.

MRI features of hepatocellular adenomas in children: clinical and radiological review

BACKGROUND

Hepatocellular adenomas (HCAs) are rare, benign hepatic tumors in children, with limited imaging data available for pediatric cases.

OBJECTIVE

To describe the magnetic resonance imaging (MRI) and clinical features of histologically proven HCAs in children.

MATERIALS AND METHODS

Single-center retrospective review of pathology-proven HCA from January 2004 to February 2024. Patients with available pre-intervention imaging in our PACS were included. Two independent readers reviewed the imaging studies. The features were summarized using descriptive statistics and inter-reader agreement was assessed using Cohen's kappa.

RESULTS

This study included 11 children (6 boys and 5 girls; median age 15 years) with 13 pathologically proven HCAs. Three patients had type 1a glycogen storage disease. Five patients had a single lesion, while six had multiple lesions. The lesions were well-defined with a median average diameter of 3.6 cm. Most were homogenously T1 iso-intense (61.5%) and mildly hyperintense (76.9%) on T2-w fat saturated images. The atoll sign was present in two lesions. Intralesional fat was observed in 69.2% of cases: microscopic in eight lesions and macroscopic in one. Hemorrhage occurred in three (23.07%) lesions and necrosis in one (7.7%). Nine out of 10 (90%) lesions showed arterial phase hyperenhancement, and only 3/10 (30%) lesions retained contrast on hepatobiliary phase. In total, 6/13 (46.1%) lesions showed washout, and all received hepatobiliary agent. One lesion ruptured with the hemoperitoneum. Of the 11, 63.6% of patients underwent percutaneous biopsy and 36.4% underwent surgical resection.

CONCLUSION

MR imaging features are nonspecific, but homogenous slight T2 hyperintensity, arterial phase hyperenhancement, and intralesional fat content are common features. Hepatobiliary contrast uptake is variable.

Gadoxetic acid-enhanced MRI in differentiating focal nodular hyperplasia from hepatocellular adenoma in children

OBJECTIVE

To investigate the diagnostic performance of gadoxetic acid (Gd-EOB)-enhanced MRI for distinguishing focal nodular hyperplasia (FNH) from hepatocellular adenoma (HCA) in children.

METHODS

Twenty-two patients (HCA, n = 6; FNH, n = 16) underwent MRI with Gd-EOB were retrospectively included in this study. The diagnosis was established by biopsy in eight patients and by imaging criteria and follow-up in 13 patients. After qualitative analyses of MRI, quantitative analyses were performed by calculating the relative signal intensity ratios (SIR) between lesion and liver parenchyma both on precontrast and hepatobiliary phase (HBP) images. Two equations, SIRpost-pre and liver-to-lesion contrast enhancement ratio (LLCER), using both SIRs of precontrast and HBP imaging together were also calculated.

RESULTS

The most distinguishing non-contrast-enhanced MRI feature of HCA was intralesional fat since all HCA contained fat but none of FNHs. All FNHs were iso- or hyperintense relative to the adjacent liver on HBP images, but all HCAs except one were hypointense. The mean SIRpost-pre and LLCER of FNH were significantly higher than that of HCA (P < .001). SIRpost-pre and LLCER provided sensitivity and specificity values of 100%.

CONCLUSION

Although intralesional fat is a strong discriminative feature for distinguishing between HCA and FNH, qualitative properties of these lesions may not be enough for confident diagnosis. Gd-EOB uptake in the HBP provides high diagnostic accuracy, but overlap can be seen. SIRpost-pre and LLCER overcome the difficulties and have the best sensitivity and specificity.

ADVANCES IN KNOWLEDGE

Gadoxetic acid-enhanced MRI is a valuable tool for differentiation of FNH and HCA in children.

"Update on pediatric primary liver tumors"

Liver masses are common in children, however primary malignant neoplasms are rare, representing only 1% of all pediatric cancers. Hepatocellular neoplasms are the most common primary liver malignancies and hepatoblastoma (HB) is the most frequently diagnosed. The incidence of HB, which is increasing, is approximately of 2 cases per million in the United States, followed by hepatocellular carcinoma (HCC). Pediatric primary liver tumors of mesenchymal origin are less common, except for benign vascular tumors (hemangiomas). Malignant mesenchymal neoplasms represent approximately 10-15% of all, the most common being embryonal sarcoma and malignant rhabdoid tumor. Malignant vascular tumors are rare, but epithelioid hemangioendothelioma (EHE) and angiosarcoma can be seen in children. The development and adoption of consensus diagnostic, therapeutic and risk-stratifying approaches for pediatric patients with malignant liver tumors has been historically challenged by their rarity and by their diverse clinical and histological appearance. On-going collaborative efforts of international consortia including the Children's Oncology Group (COG) in North America, the German Society of Paediatric Oncology and Haematology (GPOH), the Societe Internationale d' Oncologie Pediatrique Liver Tumor Study Group (SIOPEL) in Europe and the Japanese Liver Tumor group (JPLT), have made significant contributions to understanding the clinical and histopathological features, as well as the underlying biology of pediatric liver tumors, in particular HB. A new classification of pediatric liver tumors drafted at the international consensus meeting held in Los Angeles, has been incorporated in the recent WHO classification and is currently used by the PHITT (Paediatric Hepatic Malignancy International Tumour Trial) and other therapeutic protocols. This manuscript provides an overview of salient diagnostic features and updates in classification and molecular characterization for the most common pediatric primary liver neoplasms. It also includes a brief overview of other less common but relevant tumors, which should be considered in the differential diagnosis.

Update on the Pathology of Pediatric Liver Tumors: A Pictorial Review

Liver tumors in children are uncommon and show remarkable morphologic heterogeneity. Pediatric tumors may arise from either the epithelial or mesenchymal component of the liver and rarely may also show both lines of differentiation. Both benign and malignant liver tumors have been reported in children. The most common pediatric liver tumors by age are benign hepatic infantile hemangiomas in neonates and infants, malignant hepatoblastoma in infants and toddlers, and malignant hepatocellular carcinoma in teenagers. Here, we provide an up-to-date review of pediatric liver tumors. We discuss the clinical presentation, imaging findings, pathology, and relevant molecular features that can help in the correct identification of these tumors, which is important in managing these children.

Pediatric Hepatocellular Adenomas: What Is Known and What Is New?

Current understanding and classification of pediatric hepatocellular adenomas (HCA) are largely based on adult data. HCAs are rare in children and, unlike in adults, are often seen in the context of syndromes or abnormal background liver. Attempts to apply the adult classification to pediatric tumors have led to several "unclassifiable" lesions. Although typically considered benign, few can show atypical features and those with beta-catenin mutations have a risk for malignant transformation. Small lesions can be monitored while larger (>5.0 cm) lesions are excised due to symptoms or risk of bleeding/rupture, etc. Management depends on gender, age, underlying liver disease, multifocality, size of lesion, histologic subtype and presence of mutation, if any. In this review, we summarize the data on pediatric HCAs and highlight our experience with their diagnosis and management.

Hepatic adenoma in a 7-year-old girl: a case report and literature review

BACKGROUND

Hepatocellular adenomas (HCAs) are rare benign tumors of the liver that occur predominantly in women taking oral contraceptives. In children, HCAs comprise < 5% of hepatic tumors. We report a case of HCAs in a 7-year-old girl with estrogen and glucose imbalance.

CASE PRESENTATION

A 7-year-old girl was presented to our hospital with bilateral breast enlargement for 2 months, polydipsia, polyuria, polyphagia, hyperglycemia, and significant weight gain. Computed tomography (CT) showed a 7.2 cm×6.9 cm×5.3 cm round-shaped mass in the left inner lobe of the liver, ovarian ultrasound showed multiple follicles in the ovaries bilaterally, and cranial magnetic resonance imaging (MRI) showed an enlarged superior pituitary. Hematological and biochemical results were as follows: fasting glucose was 19.7 mmol/L, estradiol was 122.9 pmol/L, follicle-stimulating hormone 10.81 IU/L, luteinizing hormone 10.99 IU/L, insulin-like growth factor 1,513 ng/mL, glutamine aminotransferase 86 U/L, and alkaline phosphatase 362 U/L. Thyroid functions, methemoglobin, fetal protein, carcinoembryonic antigen, and chorionic gonadotropin were normal. The patient had a complete surgical resection of the liver tumor, and the postoperative histopathological diagnosis was HCAs. After the surgery, insulin was injected and the glucose levels were stable. During the 36-month follow-up period, neither tumor recurrence nor significant abnormalities were detected using color Doppler ultrasound of the liver. The child's precocious puberty is currently under control.

CONCLUSIONS

HCAs are particularly rare in children with liver tumors, and risk factors for the development of HCAs in children include sex hormone imbalance, obesity, Fanconi anemia (FA), glycogen storage diseases (GSDs) type I, III, and IV, galactosemia, immunodeficiency, congenital portosystemic shunts (CPSS), cardiac hepatopathy status-post Fontan procedure, Hurler syndrome, familial adenomatous polyposis, germline HNF1A mutations, and maturity-onset diabetes of the young type 3. Most HCAs are detected during a physical examination without clinical symptoms, and some patients may present with symptoms such as abdominal pain, abdominal distension, and abdominal masse. Serum liver function tests can show increased alkaline phosphatase (ALP) and γ- glutamyl transferase (GT), whereas α-Fetoprofein (AFP) levels are normal. The definitive diagnosis relies mainly on histopathological examination. Because HCAs can rupture and bleed and become malignant. Early surgical treatment is recommended after detection.

Incidental Liver Lesions in children: A practical and evidence-based approach

Incidental liver lesions are increasingly being discovered in the context of the increased use of ultrasound studies and the majority are benign. In children, although individually rare, the differential diagnosis is broad and therefore a systematic approach is of utmost importance to reduce the radiological and disease burden in children and their families. This review article collected current evidence and provides fundamental information for the clinician regarding specific differential diagnoses and unique imaging features of benign liver lesions in children. Ultimately, we propose a practical stepwise approach mainly involving clinical and radiological workup. Laboratory tests and histopathological examination may be necessary in the presence of red flags or in indeterminate lesions.

Diagnosis and Follow-up of Incidental Liver Lesions in Children

Incidental liver lesions are identified in children without underlying liver disease or increased risk of hepatic malignancy in childhood. Clinical and imaging evaluation of incidental liver lesions can be complex and may require a multidisciplinary approach. This review aims to summarize the diagnostic process and follow-up of incidental liver lesions based on review of the literature, use of state-of-the-art imaging, and our institutional experience. Age at presentation, gender, alpha fetoprotein levels, tumor size, and imaging characteristics should all be taken into consideration to optimize diagnosis process. Some lesions, such as simple liver cyst, infantile hemangioma, focal nodular hyperplasia (FNH), and focal fatty lesions, have specific imaging characteristics. Recently, contrast-enhanced ultrasound (CEUS) was Food and Drug Administration (FDA)-approved for the evaluation of pediatric liver lesions. CEUS is most specific in lesions smaller than 3 cm and is most useful in the diagnosis of infantile hemangioma, FNH, and focal fatty lesions. The use of hepatobiliary contrast in MRI increases specificity in the diagnosis of FNH. Recently, lesion characteristics in MRI were found to correlate with subtypes of hepatocellular adenomas and associated risk for hemorrhage and malignant transformation. Biopsy should be considered when there are no specific imaging characteristics of a benign lesion. Surveillance with imaging and alpha fetoprotein (AFP) should be performed to confirm the stability of lesions when the diagnosis cannot be determined, and whenever biopsy is not feasible.

Diagnostic value of color parametric imaging and contrast-enhanced ultrasound in the differentiation of hepatocellular adenoma and well-differentiated hepatocellular carcinoma

PURPOSE

To investigate the differential diagnostic value of computer-aided color parametric imaging (CPI) and contrast-enhanced ultrasound (CEUS) in hepatocellular adenoma (HCA) and well-differentiated hepatocellular carcinoma (wHCC).

METHOD

A total of 38 patients who underwent CEUS and were pathologically diagnosed with HCA (10 cases) and wHCC (28 cases) were reviewed retrospectively. The differences between the radiological features of HCA and wHCC were compared by two readers, blinded to the final diagnosis.

RESULTS

(a) Sonographic features: on gray-scale ultrasound, halo sign was more common in wHCC than in HCA (60.7% vs. 10.0%, p = 0.009). On CEUS, hyper- or isoenhancement was more common in HCA in the portal phase (90.0% vs. 50.0%; p = 0.022). On CPI mode, HCA was inclined toward centripetal enhancement (60.0% vs. 14.3% p = 0.010). HCA was characterized by the presence of pseudocapsule enhancement (50.0% vs. 14.3%; p = 0.036). Quantitative analysis showed that the arrival time of HCA was earlier than that of wHCC (12.4 ± 3.7 s vs. 15.9 ± 3.2 s; p = 0.006). (b) Interobserver agreement was improved by using CPI compared with CEUS. The diagnostic sensitivity, specificity, and accuracy of the combination were 80.0%, 85.7%, and 84.2%, respectively.

CONCLUSIONS

CEUS combined with CPI can provide effective information for the differential diagnosis of HCA and wHCC, especially for the non-experienced radiologists.

Hepatocellular Adenoma: What We Know, What We Do Not Know, and Why It Matters

In the last 2 decades there has been significant progress in research and diagnosis of hepatocellular adenoma (HCA), resulting in the establishment of a molecular and immunohistological HCA classification. This review aims to fine-tune the current expertise in order to enhance the histopathological diagnostic possibilities, by refining issues that are already known, addressing diagnostic difficulties and identifying still unknown aspects of HCA. We will discuss novel methods to identify HCA subtypes, in particular the sonic hedgehog HCAs and the interpretation of glutamine synthetase patterns for the recognition of beta-catenin mutated HCAs. The major complications of HCAs, bleeding and malignant transformation, will be considered, including the dilemmas of atypical and borderline lesions. Paragraphs on HCAs in different clinical and geographical settings, e.g. pregnancy, cirrhosis and non-western countries are included. The natural history of the different HCA subtypes in relation with age, sex and risk factors is a feature still insufficiently investigated. This is also true for the risks of clinical bleeding and malignant transformation in association with HCA subtypes. As HCA is a relatively rare tumor, a multicenter and multidisciplinary approach across geographical boundaries will be the appropriate method to establish prospective programs to identify, classify and manage HCAs, focusing on several aspects, e.g. etiology, underlying liver disease, complications, regression and growth. Updating what we know, identifying and addressing features that we do not know matters to warrant optimal patient management.

Pediatric Primary Hepatic Tumors: Diagnostic Considerations

The liver is the third most common site of abdominal tumors in children. This review article aims to summarize current evidence surrounding identification and diagnosis of primary hepatic tumors in the pediatric population based upon clinical presentation, epidemiology, and risk factors as well as classical imaging, histopathological, and molecular diagnostic findings. Readers will be able to recognize the features and distinguish between benign and malignant hepatic tumors within different age groups.