Symptoms and diagnosis of neuroblastoma

Neuroblastoma can develop in any location where the sympathetic autonomic nervous system is present.  A child with neuroblastoma may have no symptoms at all.  Its discovery may therefore be fortuitous, when a mass is detected, generally in the abdomen or thorax.  It may also be associated with abdominal pain, respiratory distress, fever in the case of metastases, disturbance of balance, or even a deterioration in the patient's general condition.
Neuroblastoma can also be identified by the appearance of compression in the spinal column or canal, which can lead to paraplegia. This is an absolute medical emergency, requiring immediate multidisciplinary care.

When neuroblastoma is suspected, the child is referred to a specialized center such as Institut Curie, to confirm the diagnosis, assess disease progression, and determine the best treatment plan. 

Medical imaging to assess neuroblastoma

Imaging tests to diagnose neuroblastoma —such as CT scans, MRI, or MIBG (meta-iodobenzylguanidine) scintigraphy, often after X-ray or ultrasound— are performed in specialized centers like Institut Curie. They are used to locate and assess tumor extension.
 

A biopsy to confirm neuroblastoma

A biopsy is generally performed under ultrasound guidance with a needle, or surgically, to allow a pathological examination of the tumor and a molecular biology analysis to confirm the diagnosis. The objective? To identify biomarkers that characterize the tumor and serve as important prognostic factors. Analysis of the MYCN gene is key. This gene may be present in up to a hundred copies in a single tumor cell, instead of the usual two. This is known as MYCN amplification, which makes neuroblastoma more aggressive. This information must be taken into account in treatment. A profile of the number of chromosomes, or segments of chromosomes (genomic profile), and the search for other genetic abnormalities, is also frequently carried out.

The ALK gene is also an important element in the molecular analysis of neuroblastoma, as it is frequently mutated in tumor cells. At Institut Curie, these mutations have been found in 10-15% of children with neuroblastoma, and even more in cases of relapse. Detection of the ALK gene makes it possible to offer targeted treatment when conventional therapies fail. 

When tumor biopsies are not possible —due to location, in infants, or in cases of relapse —Institut Curie offers a liquid biopsy based on a simple blood test. This detects genetic alterations through the presence of small fragments of circulating DNA, released by the tumor itself. Institut Curie was a pioneer in the development of this diagnostic technique by its biology laboratory, a benchmark in the fight against neuroblastoma.