What is the differential diagnosis and initial management for a child with an abdominal mass and hypertension, considering Neuroblastoma, Williams syndrome, and Hepatoblastoma?

Differential Diagnosis: Neuroblastoma is the Most Likely Diagnosis

In a child presenting with an abdominal mass and hypertension (BP 150/90), neuroblastoma is the most likely diagnosis, as hypertension is a well-recognized clinical feature of this malignancy, occurring through catecholamine excess or renal artery compression. 1, 2

Clinical Reasoning for Each Differential

A. Neuroblastoma (Most Likely)

• Abdominal mass with hypertension is a classic presentation of neuroblastoma, as patients commonly present with abdominal mass or distension along with hypertension as a specific associated finding 1
• Hypertension occurs through two mechanisms: catecholamine-secreting tumor causing elevated normetanephrine levels, or mechanical compression of renal vessels 2
• Additional supportive features to assess include: fever, weight loss, irritability, bone pain, periorbital ecchymosis ("raccoon eyes"), or opsoclonus-myoclonus-ataxia syndrome 1, 3

B. Wilms Tumor (Beckwith-Wiedemann Syndrome Context)

• While Wilms tumor presents with abdominal mass, hypertension is less characteristic compared to neuroblastoma 1, 4
• Beckwith-Wiedemann syndrome (BWS) increases risk for both Wilms tumor and hepatoblastoma, but the syndrome itself presents with distinctive features: macroglossia, omphalocele/umbilical hernia, hemihyperplasia, and overgrowth 1, 4
• If no BWS features are present, this diagnosis becomes less likely 4

C. Hepatoblastoma (Least Likely for This Presentation)

• Hepatoblastoma typically presents with abdominal mass but hypertension is not a characteristic feature 1, 5
• More commonly associated with BWS (2,280-fold relative risk), Simpson-Golabi-Behmel syndrome, or familial adenomatous polyposis 1
• Elevated alpha-fetoprotein (AFP) is the hallmark laboratory finding, present in approximately 50% of neonatal cases 5

Immediate Diagnostic Workup Algorithm

First-Line Essential Studies

1. Urinary catecholamines (VMA and HVA) - elevated in majority of neuroblastoma patients, essential for diagnosis 1, 3
2. Abdominal imaging with ultrasound initially, followed by CT or MRI to characterize the mass and assess for renal artery compression 1, 2
3. Complete blood count with differential - assess for anemia, pancytopenia 1
4. Comprehensive metabolic panel - evaluate renal function and electrolytes 1
5. Serum alpha-fetoprotein (AFP) - if hepatoblastoma remains in differential 1

Tissue Diagnosis Requirements

• Multiple core biopsies or surgical resection for definitive diagnosis, with adequate tissue for histologic and molecular evaluation (MYCN amplification, ALK mutations) 1
• Fine-needle aspiration is NOT recommended 1, 3
• Bilateral bone marrow aspirates and trephine biopsies if metastatic disease suspected 1

Hypertension Management Considerations

Critical pitfall: In catecholamine-producing neuroblastoma, hypertension management requires specific sequencing to avoid hypertensive crisis 2

• Initiate α-adrenergic blockade BEFORE β-blockade to prevent unopposed α-stimulation 2
• Consider angiotensin-converting enzyme inhibitors if renal artery compression is present 2
• Tyrosine hydroxylase inhibitors may be needed for severe catecholamine excess 2
• Multidisciplinary coordination between oncology, nephrology, and anesthesia is essential for peri-operative management 2

Syndrome-Specific Screening Context

If BWS features are identified during examination (macroglossia, hemihyperplasia, omphalocele):

• Implement standardized tumor surveillance: renal ultrasounds every 3 months through age 7 years for Wilms tumor 1, 4
• Abdominal ultrasound with AFP measurements every 3 months through age 4 years for hepatoblastoma 1, 4
• For CDKN1C mutations specifically: add neuroblastoma screening with urine catecholamines 4

Age-Related Diagnostic Considerations

• Neuroblastoma, Wilms tumor, and hepatoblastoma all occur in pediatric populations but have different age distributions 6, 7
• Hepatoblastoma is more common in neonates and infants under 2 years, with 75% survival in hemangiomas, 64% in mesenchymal hamartoma, but only 25% in hepatoblastoma 5
• The presence of hypertension strongly favors neuroblastoma regardless of age 1, 2