Overview
Wilms tumor and neuroblastoma are rare.
Most lumps are harmless.
When to get medical care
Causes
Causes include constipation, enlarged organs, and tumors.
OwieClear has pages on 5 conditions that can cause lump or swelling in a child's belly. Each shows how soon to get care.
Common causes
- Belly tumor in a child (Wilms tumor or neuroblastoma) (needs checking)Often needs care today
Rare tumors of the kidney (Wilms tumor) or nerve tissue (neuroblastoma) in young children.
- HepatoblastomaOften needs care today
The most common liver cancer in young children, usually under 3.
- NeuroblastomaOften needs care today
A cancer of immature nerve cells, most often in the adrenal gland above the kidney.
- Wilms tumor (nephroblastoma)Often needs care today
The most common kidney cancer in children, usually under age 5.
Less likely causes
- Solid pseudopapillary neoplasm of the pancreasSee a doctor if it doesn't get better
A rare, slow-growing pancreatic tumor, usually in young women.
What you can do at home
- Avoid pressing on it.
Medicines
Depends on cause.
At the doctor
Imaging.
Questions you may be asked
- Symptoms
The exam
A belly exam.
Tests
- Ultrasound
Prevention
Well-child checks.
- Regular exams
Check your symptoms
Most symptoms have more than one possible cause. The symptom checker looks at all of your symptoms together, plus your age, and shows how soon to get care.
Sources
Last updated 2026-11-13.