Benign liver tumors in pediatric patients - Review with emphasis on imaging features

Abstract

Benign hepatic tumors are commonly observed in adults, but rarely reported in children. The reasons for this remain speculative and the exact data concerning the incidence of these lesions are lacking. Benign hepatic tumors represent a diverse group of epithelial and mesenchymal tumors. In pediatric patients, most benign focal liver lesions are inborn and may grow like the rest of the body. Knowledge of pediatric liver diseases and their imaging appearances is essential in order to make an appropriate differential diagnosis. Selection of the appropriate imaging test is challenging, since it depends on a number of age-related factors. This paper will discuss the most frequently encountered benign liver tumors in children (infantile hepatic hemangioendothelioma, mesenchymal hamartoma, focal nodular hyperplasia, nodular regenerative hyperplasia, and hepatocellular adenoma), as well as a comparison to the current knowledge regarding such tumors in adult patients. The current emphasis is on imaging features, which are helpful not only for the initial diagnosis, but also for pre- and post-treatment evaluation and follow-up. In addition, future perspectives of contrast-enhanced ultrasound (CEUS) in pediatric patients are highlighted, with descriptions of enhancement patterns for each lesion being discussed. The role of advanced imaging tests such as CEUS and magnetic resonance imaging, which allow for non-invasive assessment of liver tumors, is of utmost importance in pediatric patients, especially when repeated imaging tests are needed and radiation exposure should be avoided.

Current Knowledge in Ultrasound-Based Liver Elastography of Pediatric Patients

“…The AUROC of SWE for differentiating hepatic hemangiomas from malignant hepatic tumors was 0.77 with a sensitivity of 72.7% and a specificity of 66.7%, using a cutoff value of 23.62 kPa. IContrast-enhanced ultrasound (CEUS) is used for the improved detection and characterization of focal liver lesions [75][76][77][78][79][80][81]. CEUS does not influence the measurement of liver stiffness [82].…”

Hamartomas from head to toe: an imaging overview

“…When diagnosed, these lesions are commonly .10 cm. 42 Depending on tumour size, clinical presentation is variable and may include a palpable abdominal mass, anorexia and weight loss. Large tumours can obstruct the extrahepatic bile ducts and inferior vena, leading to jaundice and lower extremity oedema.…”

“…Calcifications and foci of necrosis or haemorrhage are rare. 42 At MRI, the cystic components are generally hyperintense on T 2 weighted images and of variable signal intensity on T 1 weighted images, depending on the proteinaceous content within the cyst. 43 Solid components appear hypointense relative to the normal liver Figure 8.…”

Detection and characterization of small superficially located focal liver lesions by contrast-enhanced ultrasound with high frequency transducers

“…Early detection and characterization of small FLLs may increase the chances of curative surgical resection or successful percutaneous ablation options of malignant tumours in early stages [8,9,11,14,22,23]. Conventional BMUS with low frequency convex transducer (1)(2)(3)(4)(5) is the first line imaging method for detecting and diagnosis of FLLs [4,5].…”