Diagnosing fNHL

• Diagnosis is primarily based on a combination of a patient's clinical presentation and laboratory, radiologic, and pathologic evaluations^9,10
  • Patients with follicular lymphoma typically present with superficial lymph nodes of small to medium size, which sometimes go unnoticed by the patient¹¹
    • Primary mediastinal involvement is uncommon¹¹
    • Patients may present with B symptoms or symptoms from the slow growth of lymphoma in deep areas of the body such as the infradiaphragmatic territories¹¹
    • The GI tract is the most frequent extranodal site for follicular lymphoma¹²
    • 50% to 60% of cases have bone marrow involvement¹¹
  • Essential laboratory workup parameters include a complete blood count, serum lactate dehydrogenase (LDH) levels, and beta-₂-microglobulin (B2M) levels^9,10
  • Initial radiologic imaging studies should include computed tomography (CT)⁹
  • Fluorodeoxyglucose-positron emission tomography (¹⁸FDG-PET) scan currently is not used routinely for staging. Results can be misleading, because other organs in addition to the malignant tumors can take up the radioactive FDG^10,13
    • Lesions smaller than 1 cm cannot be reliably visualized by ¹⁸FDG-PET scanning¹⁰
    • The addition of ¹⁸FDG-PET scans to detect disease sites resulted in modification of clinical stage in 15% to 20% of patients. The impact on therapy was even smaller at 8%¹⁰
    • When ¹⁸FDG-PET scanning is used, it has generally been in conjunction with diagnostic CT scans¹⁰
• Pathologic testing includes morphologic evaluation and immunophenotyping¹⁰
  • Excisional diagnostic biopsy is critical to avoid false-negative results and inaccurate histologic classification⁹
  • In specific circumstances in which a lymph node is not easily accessible for excisional or incisional biopsy, fine needle aspiration (FNA) and core needle biopsy in combination with other techniques may be sufficient for initial diagnosis. These include: immunohistochemistry (IHC), flow cytometry, PCR, and FISH^9,10
  • FNA or core needle biopsy alone is generally not suitable for the initial diagnosis of lymphoma^9,10
• Identifying the immunophenotype can help assist in the diagnosis of the disease and in the choice of proper treatment.¹⁰ These assays should be used with other diagnostic tools
  • The 2 methods most frequently used for immunophenotyping are paraffin section IHC and cell surface marker analysis by flow cytometry¹⁰ (Table 2)
• In addition, techniques to assess the cytogenetics of the lymphoma cells may be helpful in determining whether a genetic rearrangement, such as a chromosomal translocation t(14;18) involving the Bcl-2 gene, has occurred¹⁰

Table 2. Characterizing immunophenotypes in fNHL in a heterogeneous population. These assays should be used with other diagnostic tools.^10,14-18

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