Lymphoma, Non-Hodgkin (NHL)

Key Features

Essentials of Diagnosis

• Virtually all childhood NHLs are rapidly proliferating, high-grade, diffuse malignancies

• Tumors exhibit aggressive behavior but are usually very responsive to treatment

• Can arise in any site of lymphoid tissue, including the lymph nodes, thymus, liver, and spleen

• Common extralymphatic sites include bone, bone marrow, CNS, skin, and testes

General Considerations

• Diverse group of cancers accounting for 5–10% of malignancies in children younger than 15 years

• About 500 new cases arise per year in the United States

• Incidence increases with age

• Male predominance of approximately 3:1

• Nearly all pediatric NHLs are histologically classified into four main groups

  • Lymphoblastic lymphoma

  • Small noncleaved cell lymphoma (Burkitt lymphoma and Burkitt-like lymphoma)

  • Large B-cell lymphoma

  • Anaplastic large cell lymphoma

Clinical Findings

• Lymphoblastic lymphoma

  • Airway compression (cough, dyspnea, orthopnea)

  • Superior vena cava obstruction (facial edema, chemosis, plethora, venous engorgement)

  • These symptoms are a true emergency necessitating rapid diagnosis and treatment

  • Pleural or pericardial effusions may further compromise the patient's respiratory and cardiovascular status

  • CNS and bone marrow involvement are not common at diagnosis

• Burkitt lymphoma and Burkitt-like lymphoma

  • Abdominal pain, distention, a right lower quadrant mass, or intussusception in a child older than 5 years

  • Bone marrow involvement is common (~65% of patients)

  • Burkitt lymphoma is the most rapidly proliferating tumor known and has a high rate of spontaneous cell death as it outgrows its blood supply

  • Consequently, children with massive abdominal disease frequently have tumor lysis syndrome (hyperuricemia, hyperphosphatemia, and hyperkalemia)

• Large cell lymphomas

  • Clinically similar to the small noncleaved cell lymphomas, although unusual sites of involvement are quite common

  • Skin lesions, focal neurologic deficits, and pleural or peritoneal effusions without an obvious associated mass are frequently seen

Diagnosis

Laboratory Findings

• CBC, liver function tests, and a biochemical profile (electrolytes, calcium, phosphorus, uric acid, renal function) should be obtained

• Elevated lactate dehydrogenase

  • Reflects tumor burden

  • Can serve as a marker of disease activity

Imaging

• Chest radiograph and chest CT scan, an abdominal ultrasound or CT scan, and possibly a PET scan should be considered

Diagnostic Procedures

• Bone marrow and CSF examinations are essential

• Diagnosis is made by biopsy of involved tissue with histology, immunophenotyping, and cytogenetic studies

  • Occasionally necessary to initiate corticosteroids or low-dose emergency radiation therapy until mass is small enough for biopsy to be done safely

  • Response to this approach usually prompt (12–24 hours)

Treatment

• Nearly all patients require intensive intrathecal chemotherapy for CNS prophylaxis

• Surgical resection is not indicated unless the entire tumor can be resected safely, which is rare

• Partial resection or debulking surgery has no role

• Therapy for lymphoblastic lymphoma involves dose-intensive, multiagent chemotherapy; duration of therapy is 2 ...