The lymphatic system is part of the immune system. It includes the lymph nodes, lymphatic vessels, spleen, thymus, tonsils, and bone marrow. Non-Hodgkin lymphomas develop when a lymphocyte acquires abnormalities that cause it to multiply uncontrollably.

In children, the vast majority of these lymphomas are aggressive forms, unlike the many indolent lymphomas seen in adults. They are classified based on the appearance of the cells, their immunophenotype, and their genetic or molecular characteristics.

In most cases, no cause is identified. The condition is not caused by diet, lifestyle, upbringing, or a psychological event.

An increased risk exists in some children with a congenital or acquired immune deficiency, following a transplant, or in certain genetic disorders. Viral infections may play a role in specific contexts. However, these situations account for only a small proportion of pediatric lymphomas.

Symptoms depend mainly on the location of the disease and can change rapidly.

The diagnosis is based on the analysis of tumor cells or tissue obtained via biopsy, fluid aspiration, or bone marrow aspiration, depending on the tumor’s location. The tests combine morphological analysis, immunophenotyping, cytogenetics, and molecular biology.

The specimen must be collected promptly and under appropriate conditions to ensure sufficient material is preserved for all analyses. Extensive surgery is generally not necessary to establish the diagnosis.

Staging Evaluation

This evaluation identifies the affected areas and assesses for spread to the bone marrow or the central nervous system. It may include CT, MRI, and PET-CT scans depending on the subtype, as well as a lumbar puncture and bone marrow examination. The choice of tests depends on the suspected condition and the patient’s clinical status.

Chemotherapy is the primary treatment. Its intensity, duration, and administration vary greatly depending on the type of lymphoma, the stage of the disease, the affected organs, and the patient’s response. Pediatric treatments follow established protocols and must be administered by an experienced team.

Mature B-cell lymphomas

Burkitt lymphoma and diffuse large B-cell lymphoma are treated with short, intensive courses of therapy. Rituximab, an antibody directed against CD20, is incorporated into the treatment of certain forms of mature B-cell lymphoma, particularly high-risk cases.

Lymphoblastic lymphomas

Treatment is prolonged and similar to that for acute lymphoblastic leukemia. It consists of several successive phases and includes measures to prevent central nervous system involvement.

Anaplastic large cell lymphoma

Chemotherapy remains the first-line treatment. In cases of relapse or refractory disease, treatments targeting CD30 or ALK may be considered depending on the situation and treatment protocols.

Surgery

It is primarily used to establish a diagnosis or to treat a complication. Wide excision of the mass is generally not beneficial, as these lymphomas are highly responsive to medical treatments.

Radiation therapy

It has become rare as a first-line treatment in children. It may be considered in a few specific situations, particularly for certain emergencies or refractory diseases.

Research and Innovative Treatments

Research focuses on targeted antibodies, molecular pathway inhibitors, bispecific antibodies, and CAR-T cells for certain refractory or relapsed B-cell lymphomas. Their use depends on available evidence, regulatory approval, and trial criteria.

Advances in treatment have led to high cure rates. Recent U.S. data report a five-year relative survival rate of approximately 90% for all non-Hodgkin lymphomas diagnosed before age 20. This overall figure does not predict individual outcomes.

The prognosis depends on the subtype, the extent of the disease, certain biological markers, possible involvement of the central nervous system or bone marrow, and, above all, the response to treatment. Certain localized forms are very often curable, while refractory or relapsed diseases remain more difficult to treat.

A new characterization of the disease may be necessary. The treatment strategy depends on the subtype, the site, and the time to relapse, as well as on the treatments already received. It may involve salvage chemotherapy, targeted antibodies, therapy directed against a molecular abnormality, autologous or allogeneic stem cell transplantation, or participation in a clinical trial.

Follow-up care monitors for possible relapse and long-term effects. It involves follow-up visits, clinical examinations, laboratory tests, and imaging studies tailored to the patient’s risk and symptoms.

The Department of Pediatric and Adolescent Oncology coordinates multidisciplinary care with teams from hematology, pathology, clinical laboratory medicine, imaging, intensive care, partner surgical departments, pharmacy, and supportive care. Patients treated here are between 0 and 25 years old.

Each case is discussed during a multidisciplinary team meeting. Because the disease can progress rapidly, the scheduling of tests, the prevention of complications, and the initiation of treatment are coordinated immediately.