Hematologic Malignancies: Lymphoma

I. HODGKIN’S LYMPHOMA A. Presentation 1. Subjective. Classical Hodgkin’s disease or Hodgkin’s lymphoma (HL) usually presents as painless lymphadenopathy in the cervical and/or supraclavicular regions. Isolated subdiaphragmatic lymphadenopathy or organ involvement is rare. Although staging studies reveal mediastinal adenopathy in more than 85% of patients, symptoms of cough, chest pain, dyspnea, and superior vena cava (SVC) syndrome are uncommon, even in patients with bulky mediastinal disease. Systemic symptoms or ‘‘B’’ symptoms, including fevers (temperature greater than 38◦C), drenching night sweats, or weight loss (more than 10% of baseline body weight in the preceding 6 months) occur in 30% to 40% of patients with stage III or IV disease, but in fewer than 10% of patients with stage I or II disease. In most series, the presence of B symptoms portends a worse prognosis. Generalized, severe pruritus occurs in approximately 25% of patients with HL, often precedes the diagnosis by months, can be a presenting symptom of both early and advanced-stage disease, and has no known prognostic significance. Alcohol-induced pain in involved lymph nodes is a rare symptom of HL (less than 1%). B symptoms and pruritus usually subside within a few days of initiating therapy. When HL presents in older patients or patients with the human immunodeficiency virus (HIV), B symptoms and intra-abdominal and extranodal involvement including lung, bone marrow, liver, or bone are more common. HL as well as non-Hodgkin’s lymphoma (NHL) should always be considered in the differential diagnosis of fever of unknown origin in an older patient, even without evidence of adenopathy. Nodular lymphocyte–predominant Hodgkin’s lymphoma (LPHL), which represents less than 5% of cases of HL in the United States and Europe, is often first seen as a solitary cervical, axillary, or inguinal lymph node. In LPHL, the mediastinum is generally spared, and in contrast to the contiguous pattern of lymph node involvement in classic HL, there is no consistent pattern of spread. 2. Objective. Although computed tomography (CT) scans and positron emission tomography (PET) scans have replaced the physical examination in staging, thorough examination of all lymph node–bearing areas in patients with HL remains pertinent. Occasionally small supraclavicular and infraclavicular nodes can be missed on neck and chest CT scans. In addition, chest CT scans do not always include the entire axillae, especially in larger patients. Physiologic uptake in the sternocleidomastoid muscles on PET scan may decrease the sensitivity of this test in the cervical and supraclavicular regions. Identification of all involved nodal areas is especially important in early-stage patients who may receive limited chemotherapy and ‘‘involved field’’ radiotherapy (IFRT). B. Workup and staging. HL is nearly always diagnosed by an excisional lymph node biopsy, although rarely, biopsy of an extranodal site may be the source of diagnostic tissue. Diagnosis requires the presence of Hodgkin’s or Reed–Sternberg cells (HRS) within an appropriate cellular background of inflammatory cells. Despite improved diagnostic techniques, needle biopsies should not be used as the sole source of diagnosis in HL. The most recent classification system proposed by the World Health Organization (WHO) classifies HL as either ‘‘classical’’ HL or nodular LPHL. This distinction is essential because LPHL and classical HL have different natural histories, prognoses, and treatments. Immunohistochemical studies