Neuroblastoma, Adrenal/Retroperitoneal


KEY FACTS

Terminology

  • Malignant tumor of sympathetic chain primitive neural crest cells

  • Increasing degrees of cellular differentiation/benignity along spectrum: Neuroblastoma (malignant) → ganglioneuroblastoma → ganglioneuroma (benign)

Imaging

  • Location

    • Adrenal (35-48%)

    • Extraadrenal retroperitoneum (25-35%)

    • Posterior mediastinum (16-20%)

  • Small round solitary mass vs. large multilobulated lesion

  • Aggressive tumor with tendency to invade adjacent tissues

  • Frequently engulfs & displaces adjacent vascular structures (rather than just displacing)

  • Ca²⁺ in up to 90% by CT

  • Metastases in 50-60% at diagnosis, most commonly to bone, lymph nodes, liver, soft tissues

Top Differential Diagnoses

  • Wilms tumor

  • Neonatal adrenal hemorrhage

  • Less common adrenal tumors

  • Other cystic/solid suprarenal lesions

Clinical Issues

  • Most common extracranial solid malignancy in children

  • Median age at diagnosis: 15-17 months

  • Wide variety of clinical presentations; most commonly presents as palpable abdominal mass

  • Features associated with better prognosis

    • Age at diagnosis < 18 months

    • Stage 4S/MS

    • Localized tumor not involving vital structures

    • Absent MYCN (N-myc) oncogene amplification

This graphic shows the anatomic extent of the sympathetic chain ganglia (including the adrenal glands) from the cervical region to the pelvis. Neuroblastoma (NBL) can arise anywhere along the sympathetic chain.

Supine AP abdominal radiograph in a 1-year-old boy with a palpable abdominal mass shows displacement of bowel loops
by a large, heterogeneously calcified mass
in the left abdomen.

Axial CECT in the same patient shows the large, lobulated, calcified mass
crossing the midline. The mass encases & lifts the aorta
off of the spine. These features are typical of NBL.

Anterior Tc-99m nuclear medicine bone scan in the same patient shows radiotracer uptake
throughout the heavily calcified abdominal mass. No cortical bone metastases were detected in this study. Note the intense (but normal) radiotracer uptake at the primary growth centers of the visualized bones.

TERMINOLOGY

Definitions

  • Malignant tumor of sympathetic chain primitive neural crest cells

  • Increasing degrees of cellular differentiation/benignity along spectrum: Neuroblastoma [(NBL), malignant] → ganglioneuroblastoma (GNBL) → ganglioneuroma [(GN), benign]

IMAGING

General Features

  • Best diagnostic clue

    • Partially calcified, lobulated suprarenal/paraspinal mass in infant

  • Location

    • Anywhere along sympathetic chain from neck to pelvis

      • Adrenal (35-48%)

        • 90% adrenal in prenatally detected cases

      • Extraadrenal retroperitoneum (25-35%)

      • Posterior mediastinum (16-20%)

      • Pelvis (2-3%)

      • Neck (1-5%)

      • Metastatic disease with no primary identified (1%)

  • General imaging features

    • Small, round, solitary suprarenal/paraspinal mass vs. large, lobulated lesion crossing midline

    • Aggressive tumor, may invade adjacent tissues

      • Intraspinal invasion via neural foramina

      • Kidney, muscle

    • Frequently engulfs & displaces adjacent vascular structures (rather than just displacing/compressing)

    • Ca²⁺ in up to 90% by CT

    • Metastases in 50-60% at diagnosis, most commonly to bone, lymph nodes, liver, soft tissues

      • Liver: Well-defined focal vs. extensive poorly defined lesions with hepatomegaly

      • Bone: Focally destructive cortical &/or well-defined or confluent intramedullary lesions

      • Soft tissues: Cutaneous/subcutaneous lesions may be visible on physical exam & imaging

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