Oncology · Hematologic Malignancies
The facts most likely to be tested
Diffuse Large B-Cell Lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma and presents as a rapidly enlarging, symptomatic mass.
Burkitt lymphoma is characterized by a 'starry sky' appearance on histology and is strongly associated with EBV infection and the t(8;14) translocation involving the c-myc gene.
Follicular lymphoma is an indolent B-cell malignancy associated with the t(14;18) translocation, which leads to the overexpression of the BCL-2 anti-apoptotic protein.
Mantle cell lymphoma is an aggressive B-cell neoplasm associated with the t(11;14) translocation, resulting in the overexpression of Cyclin D1.
Primary CNS lymphoma is the most common intracranial malignancy in patients with advanced HIV/AIDS and is typically associated with EBV DNA in the cerebrospinal fluid.
Marginal zone lymphoma is frequently associated with chronic inflammation or autoimmune conditions, such as H. pylori-induced MALToma of the stomach.
Excisional lymph node biopsy is the gold standard for the diagnosis of non-Hodgkin lymphoma, as fine-needle aspiration is insufficient to evaluate nodal architecture.
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A 68-year-old male presents to the clinic with a 3-month history of painless, generalized lymphadenopathy and night sweats. Physical examination reveals cervical, axillary, and inguinal lymphadenopathy. Laboratory studies show a normal complete blood count and elevated lactate dehydrogenase (LDH). A biopsy of an axillary lymph node demonstrates a nodular growth pattern of small, cleaved cells. Cytogenetic analysis reveals a t(14;18) translocation.
What is the most likely diagnosis?
Follicular lymphoma
The patient's presentation of an indolent, generalized lymphadenopathy combined with the pathognomonic t(14;18) translocation and BCL-2 overexpression confirms a diagnosis of follicular lymphoma.
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High yield triage
Etiology / Epidemiology
Most common hematologic malignancy; associated with EBV, HIV, and Helicobacter pylori.
Clinical Manifestations
Painless lymphadenopathy; B symptoms (fever, night sweats, weight loss).
Diagnosis
Excisional lymph node biopsy is the gold standard for definitive diagnosis.
Treatment
Rituximab plus chemotherapy (R-CHOP) is the standard for aggressive subtypes.
Prognosis
Prognosis depends on the International Prognostic Index (IPI) score.
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Epidemiology & Etiology
Incidence increases with age, peaking in the 6th-7th decade. Strong associations exist with immunosuppression (HIV/AIDS, transplant recipients) and chronic infections like H. pylori (MALT lymphoma). Exposure to pesticides and certain autoimmune conditions like Sjogren syndrome are established risk factors.
Pertinent Anatomy
Involves the lymphoreticular system, including lymph nodes, spleen, thymus, and bone marrow. Unlike Hodgkin lymphoma, NHL frequently presents with extranodal involvement (GI tract, skin, CNS).
Pathophysiology
Arises from malignant transformation of B-cells (85%) or T-cells. Genetic translocations, such as the t(14;18) in follicular lymphoma, lead to overexpression of oncogenes like BCL-2. This results in uncontrolled clonal proliferation and failure of apoptosis.
Clinical Manifestations
Patients present with painless, rubbery lymphadenopathy that may be localized or generalized. B symptoms—fever, drenching night sweats, and >10% weight loss—indicate systemic involvement. Superior vena cava syndrome and spinal cord compression are oncologic emergencies requiring immediate intervention.
Diagnosis
Excisional lymph node biopsy is mandatory; fine-needle aspiration is insufficient for architecture. Immunohistochemistry and flow cytometry are used to classify the subtype. PET/CT is the gold standard for staging and assessing metabolic activity.
Treatment
Indolent lymphomas may be observed, while aggressive types require R-CHOP (Rituximab, Cyclophosphamide, Doxorubicin, Vincristine, Prednisone). Doxorubicin carries a risk of dose-dependent cardiotoxicity. Vincristine is associated with peripheral neuropathy.
Prognosis
The International Prognostic Index (IPI) uses age, stage, and LDH levels to predict survival. Tumor lysis syndrome is a critical complication during induction therapy, requiring aggressive hydration and allopurinol.
Differential Diagnosis
Hodgkin Lymphoma: presence of Reed-Sternberg cells
Infectious Mononucleosis: acute onset with pharyngitis and atypical lymphocytes
Tuberculosis: associated with night sweats and pulmonary findings
Metastatic Carcinoma: usually firm, fixed, and non-tender nodes
Leukemia: primary bone marrow involvement with peripheral blasts