Neuroblastoma
- Neuroblastoma is a tumor of the sympathetic nervous system — most often arising in the adrenal gland, but it can pop up anywhere the sympathetic chain runs, from the neck to the pelvis.
- It's a disease of the very young: usually toddlers and infants, typically under age 5.
- The imaging signature is a calcified, heterogeneous mass that engulfs and displaces vessels rather than invading the kidney — it surrounds the aorta like dough wrapped around a sausage.
- It loves to cross the midline and spread to lymph nodes, bone, and bone marrow at the time of diagnosis.
- The big mimic to separate it from is Wilms tumor, which arises from the kidney and pushes vessels aside rather than swallowing them.
Imagine a tumor that doesn't politely stay in one organ but instead follows a wiring diagram. Neuroblastoma grows from the sympathetic nervous system — the "fight or flight" wiring that runs as a chain alongside your spine and balloons out into the adrenal glands. So this tumor can show up anywhere that wiring goes. Most of the time it sets up shop in the adrenal gland sitting on top of the kidney, but it has no problem appearing in the chest, the neck, or deep in the pelvis. It's one of the most common childhood cancers and the most common solid tumor outside the brain in little kids — and the single most common cancer in infants.
Who gets it, and why it's sneaky
This is a tumor of the very young — think infants and toddlers, usually diagnosed under age 5. The sneaky part is how it announces itself. Because it can sit anywhere along the sympathetic chain, the presentation is all over the map: a firm belly, bone pain that looks like a limp, or some genuinely strange paraneoplastic acts. A couple of the classics are worth knowing because they're so memorable.
Two quirky presentations get tested over and over: "raccoon eyes" — bruising around the eyes from spread to the bones behind the orbit — and opsoclonus-myoclonus, the "dancing eyes, dancing feet" syndrome where the child has chaotic eye movements and jerky limbs. Both should make you think neuroblastoma.
What it looks like on imaging
When you finally get pictures, neuroblastoma has a personality. On CT it's a heterogeneous, often bulky mass that loves calcium — coarse, blotchy calcifications show up in the majority of cases, which is a useful fingerprint. The mass is messy-looking because it's a mix of solid tumor, necrosis, and sometimes hemorrhage.
But the single most important behavior — the thing that nails the diagnosis — is what it does to blood vessels. Neuroblastoma encases vessels rather than displacing them. Picture sourdough rising around a chopstick: the dough surrounds and engulfs the chopstick without moving it. The tumor wraps around the aorta, the celiac axis, and the renal vessels, lifting the aorta away from the spine. It also happily crosses the midline, which most well-behaved tumors won't do.
The one you must not confuse it with
The most important "is it A or B" in pediatric abdominal masses is neuroblastoma versus its arch-rival from the same neighborhood. They both make a big mass near the kidney in a young child, but they behave like opposite personalities.
| Feature | Neuroblastoma | Wilms tumor |
|---|---|---|
| Origin | Sympathetic chain / adrenal (suprarenal) | Arises from the kidney itself (intrarenal) |
| Typical age | Younger — often infants/toddlers | Slightly older toddlers/preschoolers |
| Vessels | Encases and surrounds them | Displaces them, pushes them aside |
| Calcification | Common, coarse | Uncommon |
| Midline | Frequently crosses it | Usually respects it |
| Kidney | Pushes the kidney down and out, but spares it | Replaces/distorts the kidney itself |
The trap is the "claw sign." A mass arising from the kidney makes the renal tissue curve around it like a claw gripping a ball — that points to Wilms. Neuroblastoma instead sits on top of the kidney and shoves it downward and outward, so the kidney looks pushed rather than eaten. Decide who the mass belongs to before you commit.
MRI, nuclear medicine, and staging
MRI earns its keep when the tumor reaches toward the spine. Neuroblastoma along the paraspinal chain likes to sneak through the neural foramina into the spinal canal in a dumbbell shape — an hourglass with one bulb inside the canal and one bulb outside. That's a cord-compression emergency, and MRI is how you catch it.
For the whole-body picture, neuroblastoma has its own special flashlight: MIBG (a radiotracer that homes in on sympathetic tissue) lights up both the primary tumor and its metastases, which is why it's central to staging and follow-up.
Neuroblastoma is famous for one of oncology's strangest plot twists. In a subset of infants, even widely spread disease can spontaneously regress or mature into something benign. So "lots of disease everywhere" doesn't carry the same grim meaning it would in an older child — age and biology matter enormously here.
The one thing to remember
If you remember nothing else: neuroblastoma is the suprarenal mass in a small child that calcifies, crosses the midline, and wraps itself around vessels instead of pushing them away. Find a mass that's behaving like dough around a chopstick, and you're already most of the way to the answer.