Paediatrics: Lymphoma

Lymphoma

There are two distinct disease entities that differ in regard to natural his-tory, presentation, and management. Both are more common in boys than girls.

Non-Hodgkin’s lymphoma (NHL)

The annual incidence of NHL is 10 per million. The majority are high-grade tumours that are divided into categories, using histology, immunopheno-type, and cytogenetics.

NHL staging (St Jude system)

Stage I: single site or nodal area (not abdomen or mediastinum).

Stage II: regional nodes, abdominal disease.

Stage III: disease on both sides of the diaphragm.

Stage IV: bone marrow or CNS disease.

Investigations

Tissue: bone marrow aspirate; lumbar puncture; pleural and abdominal

(peritoneal) fluid aspirate; exclusional biopsy.

Imaging: CT and positron emission tomography (PET) scans.

Treatment

Lymphoblastic (T cell, pre-B cell) lymphoma is treated like ALL. Mature B cell disease is treated with short series of dose-intensive courses of che-motherapy. Risk of tumour lysis  is high.

Prognosis 

Survival is >70% (>90% in those with localized disease).

Hodgkin’s Lymphoma

The incidence of Hodgkin’s Lymphoma (HL), or Hodgkin’s Disease, is very low before age 5yrs and rises with age. It is more common in patients with previous EBV infection. The histology shows Reed–Sternberg cells in an apparently reactive lymph node infiltrate.

Presentation 

Progressive, painless lymph node enlargement, the most common sites be-ing cervical (80%) and mediastinal (60%). Dissemination to extranodal sites is less common, lungs and bone marrow being most frequently involved. Fever, night sweats, weight loss (>10%) constitute ‘B’ symptoms and are common in advanced stages.

Subtypes

HL is divided into two subtypes, which are then further subdivided by histology. Classical HL includes nodular sclerosing (most common), mixed cellularity, and lymphocyte-depleted histology. Nodular lymphocyte– predominant HL is the other subtype, characterized by its distinctive his-tology and favorable prognosis.

Staging (Ann Arbor system)

·Stage I: single site.

Stage II: more than one site and on one side.

Stage III: on both sides of the diaphragm.

Stage IV: disseminated disease.

Investigations

·CT of neck, chest, abdomen, and pelvis.

·FDG PET scan.

·Bone marrow aspiration and trephine (if radiological evidence of at least stage III disease).

·EBV serology and ESR.

·Isotope bone scan (generally done with stage IV disease, evidence of bone pain, or B symptoms).

Treatment

National practices differ, influenced by the balance between cure and ad-verse long-term effects. Low stage disease may be cured with involved field radiotherapy alone, but chemotherapy with low dose involved field radiotherapy for selected cases is now more commonly employed. Chemotherapy usually includes alkylating agents, vinca alkaloids, anthra-cyclines and steroids, and the addition of radiotherapy is considered es-sential at least for bulky mediastinal or stage IV disease. Reductions and augmentations of these therapies is being explored in the context of clini-cal trials and the role of PET scanning is likely to play an increasing role in monitoring of disease and determination of therapy.

Prognosis 

5-yr survival >90% (stage IV, 70%; stage I, 97%).

Relapse 

Cure is still possible with second line therapy, including autolo-gous stem cell transplant.