The incidence of Hodgkin disease has a bimodal distribution with peaks in the adolescent/young adult years and again after age 50; it is rarely seen in children younger than 5 years of age. In children, boys are affected more commonly than girls; in adolescents, the gender ratio is approximately equal. The incidence of NHL increases with age. It is more common in whites than in African Americans and in males than in females. NHL has been described in association with congenital or acquired immunodeficiency states and after organ or stem cell transplantation. Burkitt lymphoma commonly is divided into two forms: a sporadic form commonly seen in North America and an endemic form commonly seen in Africa, which has a strong association to EBV.
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The most common clinical presentation of Hodgkin disease is painless, firm lymphadenopathy often confined to one or two lymph node areas, usually the supraclavicular and cervical nodes. Mediastinal lymphadenopathy producing cough or shortness of breath is another frequent initial presentation. The presence of one of three B symptoms has prognostic value: fever (>38° C for 3 consecutive days), drenching night sweats, and unintentional weight loss of 10% or more within 6 months of diagnosis.
The sporadic (North American) form of Burkitt lymphoma more commonly has an abdominal presentation (typically with pain), whereas the endemic (African) form frequently presents with tumors of the jaw. The anterior mediastinum and cervical nodes are the usual primary sites for T-cell lymphomas. These lymphomas may cause airway or superior vena cava obstruction, pleural effusion, or both.
The diagnosis of lymphoma is established by tissue biopsy orexamination of pleural or peritoneal fluid. Systemic symptoms,such as fever and weight loss, may be present and are particularly prominent in patients with anaplastic large cell lymphoma,which can be insidious in onset. If the bone marrow contains 25% or greater blasts, the disease is classified as acute leukemia (either B-cell acute lymphoblastic leukemia [ALL] or T-cellALL). This distinction makes little prognostic or therapeuticdifference because both require aggressive, systemic therapy inaddition to CNS-directed therapy.
Patients suspected to have lymphoma should have a complete blood count, erythrocyte sedimentation rate, and measurement of serum electrolytes, calcium, phosphorus, lactate dehydrogenase, and uric acid. A chest x-ray assesses for a mediastinal mass (Fig. 156-1). The diagnosis ultimately requires a pathologic confirmation from tissue or fluid sampling. For staging purposes, a bone marrow aspirate, bone scan, and positron emission tomography or gallium scan also are indicated. The pathologic hallmark of Hodgkin disease is the identification of Reed-Sternberg cells. Histopathologic subtypes in childhood Hodgkin disease are similar to those in adults; 10% to 15% have lymphocyte predominant, 50% to 60% have nodular sclerosis, 30% have mixed cellularity, and less than 5% have lymphocyte depletion. All subtypes are responsive to treatment. Staging of Hodgkin disease is according to the Ann Arbor system. Staging laparotomy is no longer used in children because computed tomography scans often identify abdominal (lymph nodes, liver, spleen) involvement.