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CASE HISTORY • Part 1
A 46-year-old man seeks evaluation of a non-tender mass that he recently discovered in his left axilla. He notes that it seems to have been enlarging rapidly over the past 3 weeks. He is otherwise feeling well, with no weight loss, fever, or chills, and has no significant past medical history, nor any family history of hematologic disease.
On examination, in addition to the 5–6 cm mass that the patient noted, multiple 1- to 2-cm lymph nodes are found in both axillae and in the cervical region. All of these are non-tender, mobile, and rubbery in texture. There is no hepatosplenomegaly or palpable abdominal masses; the only other finding of significance is the presence of mild bilateral pitting edema in the lower extremities.
The patient's complete blood count (CBC) is entirely normal; no abnormal cells are noted on examination of the blood smear.
Question
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The non-Hodgkin lymphomas (NHLs) are disorders characterized by malignant proliferation of B or T lymphocytes. From a clinical standpoint, lymphomas generally present as tumors of the lymphoid system—the lymph nodes, Waldeyer ring, spleen, blood, and marrow. However, since lymphocytes by their nature are heterogeneous and have access to nearly every anatomic site, the NHLs may present with involvement of any organ, including the central nervous system. With advances in clinical and pathological staging techniques, the ability to accurately diagnosis a specific NHL disorder and predict the course of the disease in an individual patient has greatly improved. It has also made it possible to plan an optimal course of treatment.
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The etiological mechanisms involved in lymphomagenesis are yet to be fully understood. Environmental factors, including radiation, chemical exposures, and both viruses and bacteria (human T-cell lymphotrophic virus type 1 [HTLV-1], hepatitis C virus [HCV], Epstein-Barr virus, Helicobacter pylori, and Campylobacter jejunii) clearly play a role in many of the NHL subtypes. Genetic predisposition is also a major factor. This is best illustrated by the recurrent genetic abnormalities observed in NHL disorders, including translocations or mutations involving proto-oncogenes, signal transduction factors, cell cycle regulation, and apoptotic pathways. Epigenetic factors are almost certainly another important etiological mechanism in NHL.
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The importance of accurate diagnosis and effective management of lymphomas has been heightened by their increasing incidence, the association of lymphomas with immune deficiency states, and concomitant improvements in therapy. The incidence in Western countries has more than doubled in the last 20 years not only because of the association of B-cell lymphomas with AIDS, but also likely due to greater exposure to chemical agents in the environment.
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NHL in general is very responsive to therapy, and in most cases the physician can offer the patient with NHL both improved survival and quality of life. It is a paradox that the NHL patient with the most aggressive form of the disease can actually be offered ...