Hepatoblastoma is a rare form of liver cancer that primarily affects young children, typically those under three years of age. This malignant tumor originates in the liver tissues and is the most common primary liver cancer in the pediatric population. Ultrasound is a key medical imaging tool used in the diagnosis and evaluation of hepatoblastoma, providing important insights for parents and caregivers. This article details what ultrasound shows and the subsequent steps in managing this condition.
Understanding Hepatoblastoma Ultrasound
Ultrasound is a non-invasive imaging technique that uses high-frequency sound waves to create real-time images of internal organs and structures. For hepatoblastoma, ultrasound serves several purposes, including initial detection and assessing tumor characteristics. Ultrasound is also used to monitor how the tumor responds to treatment over time. It is a preferred method for screening children at high risk of developing hepatoblastoma, such as those with certain genetic conditions like Beckwith-Wiedemann syndrome, with screening typically occurring every three months until age four. It is favored due to its safety, lack of radiation exposure, widespread availability, and lower cost compared to other imaging tests.
Preparing for and Undergoing the Ultrasound
Preparing a child for a hepatoblastoma ultrasound involves specific instructions. Depending on the child’s age, a period of fasting may be required to reduce gas in the abdomen, which can interfere with sound wave transmission. Parents should dress their child in comfortable, loose-fitting clothing that allows easy access to the abdominal area.
During the procedure, the child typically lies on an examination table. A clear, water-based gel is applied to the skin over the abdomen to help the transducer glide smoothly and ensure good contact. The sonographer then gently moves the transducer across the child’s abdomen, and the sound waves bounce off the liver and tumor, creating images on a monitor. The procedure is generally painless and brief. Keeping a young child calm can involve bringing a favorite toy, book, or pacifier.
What Ultrasound Images Show
On ultrasound, hepatoblastomas often appear as solid masses, which are predominantly echogenic, meaning they reflect sound waves strongly and appear brighter on the image. Larger tumors may show heterogeneity, appearing less uniform due to varying tissue compositions, including areas of necrosis (dead tissue) or hemorrhage (bleeding). Calcifications, which are deposits of calcium, can also be present within the tumor and may appear as bright spots with shadowing behind them.
Ultrasound allows for the assessment of the tumor’s size and its relationship to the surrounding healthy liver tissue. It can also help identify if the tumor has displaced or invaded major blood vessels like the portal vein, which is a significant factor in determining resectability. While less common, ultrasound can also detect other findings such as ascites (fluid accumulation in the abdomen) or enlarged lymph nodes.
Next Steps After Ultrasound
Following an ultrasound that suggests hepatoblastoma, further diagnostic steps are necessary to confirm the diagnosis and plan treatment. More detailed imaging may be required, often including magnetic resonance imaging (MRI) or computed tomography (CT) scans. These offer a more comprehensive view of the tumor’s extent and its relationship to nearby structures, assisting in precise staging.
A tissue biopsy is performed to definitively confirm the diagnosis of hepatoblastoma and determine its specific histological subtype. This involves obtaining a small sample of the tumor for microscopic examination. The results from all imaging studies and the biopsy are then reviewed by a multidisciplinary team of specialists, including pediatric oncologists, surgeons, and radiologists. This ensures a comprehensive understanding of the tumor and leads to an individualized treatment plan for the child.