What is the most common intra-abdominal solid tumor in children?

Neuroblastoma is the Most Common Intra-abdominal Solid Tumor in Children

Neuroblastoma is the most common intra-abdominal solid tumor in children, making option (b) neuroblastoma the correct answer. 1, 2, 3

Evidence Supporting Neuroblastoma as the Most Common Intra-abdominal Solid Tumor

The 2024 NCCN Guidelines for Neuroblastoma clearly state that "neuroblastoma is the most common extracranial solid tumor diagnosed in children" 1. This is further supported by multiple research studies:

• Neuroblastoma accounts for approximately 11% of all pediatric cancers and 15% of all pediatric cancer deaths 3
• 70% of neuroblastomas occur in the abdomen, making it the predominant intra-abdominal solid tumor in the pediatric population 2
• Neuroblastoma has a peak age of onset of 22 months 3

Comparison with Other Options

Nephroblastoma (Wilms Tumor)

While nephroblastoma (option a) is an important pediatric renal tumor, it is less common than neuroblastoma in the overall intra-abdominal category. Nephroblastoma is primarily a renal tumor, whereas neuroblastoma has a broader distribution within the abdomen.

Rhabdomyosarcoma

Rhabdomyosarcoma (option c) can occur in the abdomen but is more commonly found in the head and neck region, extremities, and genitourinary tract 4. It is not the most common intra-abdominal solid tumor in children.

Fibrosarcoma

Fibrosarcoma (option d) is a rare soft tissue sarcoma that can occur in children but is much less common than neuroblastoma as an intra-abdominal tumor.

Clinical Characteristics of Neuroblastoma

Neuroblastoma originates from neural crest cells and has several important clinical features:

• Most commonly presents as an abdominal mass (70% of cases) 2
• Often diagnosed at advanced stages with 70% having metastases at diagnosis 2
• Can spread via direct extension through the subperitoneal space 5
• Imaging characteristics include calcifications on plain radiographs and heterogeneous enhancement on CT/MRI 6
• May present with symptoms including abdominal pain, respiratory distress due to diaphragmatic pressure, and inferior vena cava obstruction 7

Staging and Prognosis

Prognosis varies significantly based on age and stage:

• Children under one year of age have better outcomes
• Stage I disease (8% of patients) has the best prognosis
• Stage IV disease has only a 3% survival rate 2
• Current treatment protocols have improved outcomes, but long-term survival rates for high-risk patients remain <50% 3

Treatment Approach

Treatment is multimodal and includes:

• Surgical removal as primary therapy when possible
• Radiation therapy, particularly beneficial for stage III disease
• Chemotherapy regimens, often with autologous stem cell transplantation for advanced disease
• Immunotherapy as an emerging treatment modality 2, 3

In conclusion, neuroblastoma is definitively the most common intra-abdominal solid tumor in children, making option (b) the correct answer to this question.