Questions and Answers
What are the typical characteristics of Kikuchi necrotizing lymphadenitis?
Focal, well-circumscribed, paracortical necrotizing lesions with abundant karyorrhectic debris, scattered fibrin deposits, and mononuclear cells, but an absence of intact neutrophils.
Which of the following diseases is characterized by the presence of numerous eosinophils in the lymph node?
Sarcoidosis is less common in blacks than in whites in the United States.
False
What is the most common location of lymphadenopathy in patients with tuberculosis?
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Which of the following tests is used for diagnosing sarcoidosis?
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What organisms are primarily responsible for mesenteric lymphadenitis?
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The basic lesion of sarcoidosis is a small _______ mainly composed of epithelioid cells.
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Toxoplasmosis is primarily caused by a viral infection.
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Match the following diseases with their characteristic features:
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What are the common features of lymph nodes in cat-scratch disease?
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Lymphogranuloma venereum is caused by Chlamydia trachomatis.
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What is the initial lesion in lymphogranuloma venereum?
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The agent of cat-scratch disease is Bartonella ______.
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Which of the following diseases can cause similar changes in lymph nodes?
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The lymph node changes in lupus erythematosus are generally specific.
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What microscopic change is observed in nodes affected by infectious mononucleosis?
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Which feature is characteristic of Castleman disease?
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What type of Castleman disease presents as a single mass?
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Which type of Castleman disease is usually asymptomatic?
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Multicentric Castleman disease is often associated with viral infection.
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What is the characteristic morphology of HHV8+ Castleman disease?
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What is the first line of treatment for solitary Castleman disease?
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The multicentric form of Castleman disease presents with __________ lymphadenopathy.
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Castleman disease is classified solely as a reactive or inflammatory condition.
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What type of cells are found in large numbers in interfollicular areas of Castleman disease?
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In which region is Castleman disease most commonly reported?
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Whipple disease can cause enlargement of mesenteric lymph nodes and formation of lipophagic granulomas.
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What organism is responsible for Whipple disease?
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Which categories are malignant lymphomas divided into?
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Lipophagic granulomas are most commonly found in _____ individuals.
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What is the major alteration defined as a collection of mononuclear and multinucleated giant cells?
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Mineral oil ingestion has no observed effects in lymph nodes.
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What is the primary symptom of the disease that may appear later in its progression?
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Study Notes
Inflammatory/Hyperplastic Diseases Overview
- Characterized by abnormal proliferation of cells within lymph nodes, often in response to infections or autoimmune diseases.
- Common conditions include acute and chronic nonspecific lymphadenitis, Kikuchi necrotizing lymphadenitis, tuberculosis, atypical mycobacteriosis, and sarcoidosis.
Acute Nonspecific Lymphadenitis
- Microscopic changes start with sinus dilation from increased lymph flow, leading to neutrophil accumulation, vascular dilation, and capsule edema.
- Associated with infections like staphylococcal, mesenteric lymphadenitis, lymphogranuloma venereum, and cat-scratch disease.
- Necrotizing features may be indicated in infections such as bubonic plague, tularemia, anthrax, and melioidosis.
- Lupus lymphadenitis can mimic Kikuchi disease but should be distinguished by the presence of hematoxylin bodies.
Chronic Nonspecific Lymphadenitis
- Merges morphologically with lymphadenitis hyperplasia, showing follicular hyperplasia and increased postcapillary venules.
- Common morphological features include an increase in immunoblasts, plasma cells, histiocytes, and fibrosis.
- Presence of numerous eosinophils can suggest conditions like Langerhans cell histiocytosis, Hodgkin lymphoma, or autoimmune disorders.
Kikuchi Necrotizing Lymphadenitis
- Primarily seen in Japan and among young women, characterized by painless cervical lymphadenopathy and fever.
- Histological appearance features necrotizing lesions with karyorrhectic debris and absence of intact neutrophils.
- Diagnosis requires demonstration of necrosis due to cytotoxic lymphocyte-mediated apoptosis.
Tuberculosis
- Lymph nodes may adhere to form a multinodular mass, clinically resembling metastatic carcinoma.
- Commonly presents as cervical lymphadenopathy ("scrofula") which may develop draining sinuses.
- Microscopic examination reveals non-caseating granulomas, often with necrotic centers – important to rule out other causes.
Atypical Mycobacteriosis
- Common cause of granulomatous lymphadenitis, particularly in children.
- Granulomatous response may mimic tuberculosis but generally presents with less defined granulomas.
- Acid-fast bacilli staining is essential for diagnosis in cases of granulomatous lymphadenitis.
Sarcoidosis
- A systemic granulomatous disease with a higher prevalence in Black individuals and Scandinavian countries.
- Involves multiple organs, with lung and lymph nodes primarily affected, often preceded by erythema nodosum.
- Characterized histologically by non-caseating granulomas with cells exhibiting activation markers (e.g., CD4+ T cells).
- Kveim test evaluates sarcoidosis presence but is now rarely performed.
Fungal Infections
- Fungal lymphadenitis can present in diverse ways, either as chronic suppurative lesions or granulomatous processes.
- Histoplasmosis is a significant cause, resulting in widespread nodal necrosis alongside diffuse hyperplasia of sinus histiocytes.### Fungal Diseases Causing Lymphadenitis
- Blastomycosis, paracoccidioidomycosis, coccidioidomycosis, and sporotrichosis are known to cause lymphadenitis.
- Opportunistic fungal infections include cryptococcosis, aspergillosis, mucormycosis, and candidiasis.
- Fungal organisms can be detected using Gomori methenamine silver (GMS) or PAS–Gridley stains, culture, or molecular testing.
Toxoplasmosis
- Caused by the protozoan Toxoplasma gondii, affecting humans and warm-blooded animals.
- Characterized by small non-caseating granulomas and massive monocytoid B-cell hyperplasia in lymph nodes.
- Toxoplasma organisms are rarely found in lymph nodes through morphologic examination; detection often relies on serological tests.
Syphilis
- Generalized lymphadenopathy is common in secondary syphilis; localized lymph node enlargement occurs in primary and tertiary stages.
- Secondary syphilis presents with florid follicular hyperplasia, while primary infection may mimic malignant lymphoma.
- Histological features include capsular inflammation, extensive fibrosis, and a combination of plasma cell infiltration and vascular proliferation.
- Treponema pallidum can be identified by Warthin–Starry or Levaditi stains, immunofluorescence, or PCR tests.
Leprosy
- Associated with lepromatous leprosy, characterized by large, pale rounded histiocytes without granuloma formation.
- Stains like Wade–Fite and Fite–Faraco demonstrate acid-fast organisms in lymph node cytoplasm.
- Diagnosis confirmed through fluorescent methods or PCR.
Mesenteric Lymphadenitis
- Caused by Yersinia pseudotuberculosis or Yersinia enterocolitica, presenting as a benign condition simulating acute appendicitis.
- Microscopic features include capsular thickening, edema, and germinal center hyperplasia.
- Histological findings differ between Y. pseudotuberculosis (small granulomas and abscesses) and Y. enterocolitica.
Cat-Scratch Disease
- Characterized by a primary lesion at the inoculation site and marked axillary or cervical lymphadenopathy.
- Microscopy shows stellate necrosis and monocytoid B-cell accumulation in lymph node sinuses.
- Diagnosis can be confirmed using Warthin–Starry stain, immunohistochemistry, or PCR for Bartonella henselae.
Lymphogranuloma Venereum
- Caused by Chlamydia trachomatis (serotypes L1, L2, L3), leading to a small genital ulcer and prominent inguinal adenopathy.
- Characteristic features include initial necrotic foci in lymph nodes evolving into stellate abscesses.
- Diagnosis confirmed through the Frei test, serologic testing, and molecular methods.
Tularemia
- Caused by Francisella tularensis, a highly virulent pathogen associated with severe lymphadenopathy.
- Prominent axillary lymphadenopathy noted if caused by mammalian vectors, cervical or inguinal if by arthropod vectors.
- Diagnosis supported by serological tests, especially a rise in hemagglutinin titers.
Brucellosis
- Caused by Brucella species, transitioning from occupational to foodborne illness through dairy consumption.
- Symptoms include fever, hepatomegaly, splenomegaly, and occasionally lymphadenopathy.
- Microscopy reveals nonspecific follicular hyperplasia and clusters of epithelioid histiocytes forming large non-caseating granulomas.### HIV and Related Lymphadenopathy
- Polymorphic infiltrate in lymph nodes consists of eosinophils, plasma cells, and immunoblasts, resembling Hodgkin lymphoma.
- Abnormal germinal centers are associated with HIV core protein P24; diagnosis requires immunostaining or serologic study.
- Untreated AIDS patients may exhibit lymphocyte depletion and abnormal germinal centers, which should not be misconstrued as specific for AIDS.
- Interfollicular tissue shows vascular proliferation, with a potential resemblance to Castleman disease.
- Lymph nodes should be checked for early signs of Kaposi sarcoma, particularly in areas of significant vascular changes.
Chronic Lymphadenopathy Syndrome
- Defined as node enlargement lasting over three months at two or more extrainguinal sites in individuals at risk for AIDS.
- Similar microscopic features to those found in previous discussions.
- Around 25% of patients may develop AIDS, with cachexia and weight loss as progression indicators.
Infectious Mononucleosis
- Classic infectious mononucleosis is chiefly caused by Epstein-Barr Virus (EBV).
- Diagnosis generally confirmed through peripheral blood examination and serologic tests rather than lymph node biopsy.
- Lymph nodes exhibit architecture effacement due to polymorphic lymphoid infiltrate, resembling malignancies.
- Histology shows a mix of immature plasma cells and immunoblasts; distinct features include large vesicular nucleoli and paranuclear "hof".
Other Viral Lymphadenitides
- Lymph nodes affected by smallpox vaccination can appear malignantly transformed, characterized by extensive cellular proliferation.
- Features similar to viral lymphadenitis from herpes simplex, displaying immunoblastic proliferation and potential viral inclusions.
- Distinct changes post-vaccination include clusters of varying-sized lymphocytes and a mottled appearance due to immunoblasts.
Kawasaki Disease
- Kawasaki syndrome involves prominent cervical lymphadenopathy, fever, and mucocutaneous symptoms in children.
- Can lead to coronary artery damage in approximately 25% of untreated cases; may be indicated by the presence of thrombi in lymph nodes.
Lupus Erythematosus
- Nodal changes in lupus usually exhibit moderate follicular hyperplasia and non-specific features.
- Presence of DNA-containing basophilic material in subcapsular regions is noteworthy.
Rheumatoid Arthritis
- Generalized lymphadenopathy can occur; may precede arthritis, raising lymphoma suspicion.
- Key findings include plasma cell proliferation, follicular hyperplasia, and vascular changes, often resembling Castleman disease.
Castleman Disease
- Represents a lymph node proliferation with unknown etiology, mainly affecting adults.
- Two major microscopic types:
- Hyaline-vascular type shows large follicles, vascular proliferation, and hyalinized germinal centers.
- Intermediate type exhibits a mixture of follicular and vascular changes, potentially causing diagnostic confusion with other diseases.
Diagnostic Considerations
- Immunophenotyping and in situ hybridization are valuable tools in distinguishing between infectious mononucleosis, Hodgkin lymphoma, and other lymphoproliferative disorders.
- Accurate diagnosis of lymphadenopathy in various contexts demands careful histological examination.
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Description
Test your knowledge on inflammatory and hyperplastic diseases, including their characteristics and pathological features. This quiz covers important aspects such as paracortical hyperplasia and monocytoid B-cell hyperplasia associated with specific conditions like toxoplasmic lymphadenitis.
