Does a normal brain, face, and orbit Magnetic Resonance Imaging (MRI) with contrast rule out neuroblastoma?

No, a normal brain, face, and orbit MRI with contrast does NOT rule out neuroblastoma

Neuroblastoma is a peripheral nervous system tumor that arises from neural crest cells along the sympathetic chain—primarily in the abdomen (adrenal gland and paraspinal regions), chest, and pelvis—not in the brain, face, or orbits. 1, 2 A brain/face/orbit MRI examines the wrong anatomic regions entirely for this malignancy.

Understanding Neuroblastoma Location and Imaging

Primary Tumor Sites

• Neuroblastoma is an extracranial solid tumor that most commonly presents in the abdomen (65% of cases, particularly adrenal gland), posterior mediastinum (15-20%), neck (5%), and pelvis (5%) 1, 3
• The tumor arises from sympathetic nervous system tissue along the paravertebral sympathetic chain, not from cranial structures 2, 3
• Approximately 90-95% of neuroblastomas occur in children younger than 5 years of age, with peak incidence before age 2 1

Appropriate Imaging Modalities

• The preferred diagnostic imaging for neuroblastoma is ¹²³I-MIBG (metaiodobenzylguanidine) scintigraphy, which accumulates in neuroblastoma cells in 90-95% of cases and detects the primary tumor and metastases in bone, bone marrow, lymph nodes, and soft tissues 1
• Cross-sectional imaging with CT or MRI of the chest, abdomen, and pelvis is essential for identifying the primary tumor, assessing image-defined risk factors, and evaluating local extension 4, 3
• ⁹⁹ᵐTc-disphosphonate bone scintigraphy is used to diagnose skeletal metastases 1
• FDG-PET/CT is increasingly utilized for staging and response assessment 1

Why Brain/Face/Orbit MRI Misses Neuroblastoma

Coverage Limitations

• MRI of the brain, face, and orbits does not image the abdomen, chest, or pelvis where neuroblastoma primary tumors are located 5, 6
• The standard "MRI orbits, face, and neck" protocol covers from the orbits through the neck but stops at approximately the thoracic inlet, missing the chest, abdomen, and pelvis entirely 5
• Even when "MRI orbits, face, and neck" includes the neck, it does not extend caudally enough to capture thoracic, abdominal, or pelvic pathology 5

Metastatic Disease Considerations

• While neuroblastoma can metastasize to bone (including skull), bone marrow, lymph nodes, liver, and skin, approximately 50% of patients have metastases at presentation 1
• Orbital metastases (raccoon eyes) can occur but are manifestations of disseminated disease, not the primary tumor, and would require imaging of the primary site for diagnosis and staging 1, 3
• A normal brain/face/orbit MRI could miss extensive abdominal or thoracic primary disease with or without metastases to other sites 1

Critical Clinical Pitfall

The most dangerous error is assuming that imaging of the head and neck region can exclude neuroblastoma. If clinical suspicion exists (abdominal mass, bone pain, periorbital ecchymosis, opsoclonus-myoclonus syndrome, elevated urinary catecholamines), the correct initial imaging is:

• Abdominal/pelvic CT or MRI to identify the primary tumor 4, 3
• ¹²³I-MIBG whole-body scintigraphy for comprehensive staging 1
• Chest imaging (CT or MRI) if thoracic primary is suspected 3
• Bone scintigraphy or skeletal survey for metastatic evaluation 1

In summary: A normal brain, face, and orbit MRI provides no information about the presence or absence of neuroblastoma because it images the wrong anatomic regions for this tumor. 1, 2, 3