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Cite this page: DePond WD, Kutty SVM, Pernick N. Other infections. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lymphnodesotherinfections.html. Accessed October 28th, 2021.
Actinomyces

Definition / general
  • Rare
  • Associated with poor dental hygiene (is a normal inhabitant of the oral cavity)
  • Causes lymphadenopathy

Gram stain
  • Gram positive, filamentous branching bacteria

Treatment
  • Appropriate dental care and antibiotics

Case reports

Gross description
  • Tan-white cut surface, multiple pinpoint white spots

Microscopic (histologic) description
  • Marked capsular fibrotic thickening with thick fibrous bands dividing nodes into nodules
  • Also follicular hyperplasia, marked interfollicular fibrosis and multiple interfollicular microabscesses containing focal Actinomyces colonies with classic sulfur granules (may require deeper levels to identify)
  • No palisading of histiocytes around the abscesses
  • Numerous macrophages are present in germinal centers

Microscopic (histologic) images

Images hosted on other servers:
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Cervical cytology



Differential diagnosis

Additional references
Bacillary angiomatosis

Definition / general
  • Caused by Bartonella (formerly Rochalimaea) henselae, which also causes cat-scratch disease
  • May also be caused by Bartonella quintana (Ann N Y Acad Sci 2005;1063:302)
  • Almost all patients are HIV+ or otherwise immunosuppressed
  • May have multiple red / violet skin lesions resembling Kaposi sarcoma but also involves lymph nodes and spleen
  • Bacterial reservoir is domestic cats (transmit to humans) and cat fleas (transmit to other cats)
  • May appear neoplastic but is reactive

Gram stain
  • Small, curved, motile, gram negative rod that is difficult to culture

Diagnosis
  • PCR

Case reports

Treatment
  • Erythromycin, other macrolides or doxycycline are very effective

Microscopic (histologic) description
  • Focal nodal effacement by multiple coalescing intranodal clusters of small blood vessels, lined by epithelioid endothelial cells with pale cytoplasm
  • May have focal nuclear atypia
  • Interstitium contains abundant eosinophilic to amphophilic, amorphous or granular material containing aggregates of bacteria (highlighted by Warthin-Starry stain)
  • Also neutrophils

Microscopic (histologic) images

AFIP images
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Multinodular; confluent nodules

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Ectatic vessels

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Barely canalized proliferated blood vessels

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Eosinophilic material

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Foamy histiocytes

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Warthin-Starry stain



Differential diagnosis

Additional references
bCG

Definition / general
  • Post vaccination bacille Calmette-Guerin infection occurs in 1% of infants, although swelling usually subsides (Braz J Med Biol Res 2004;37:697)
  • Patients with normal immunity have complete recovery after postvaccination bCG infection after excision of infected lymph node; immunosuppressed patients may require antiTB therapy to avoid fatal disseminated infection (Am J Clin Pathol 2000;113:703)

Case reports

Treatment

Microscopic (histologic) description
  • Patients with normal immunity:
    • Multiple epithelioid granulomas and Langhans giant cells
    • Variable suppuration, minimal caseous necrosis
    • Few acid fast bacteria identified with Ziehl-Neelsen stain
  • Immunosuppressed patients:
    • Histiocytes with abundant gray cytoplasm containing numerous acid fast bacilli, plump nuclei

Cytology description
  • Poorly to moderately cellular smears of epithelioid histiocytes in a granuloma pattern with occasional multinucleated Langerhans type giant cells, lymphocytes and neutrophils
  • Background is finely granular with necrotic debris
  • Isolated calcified spherules (Diagn Cytopathol 2001;25:134)
  • May be heavy involvement of acid fast bacilli (World J Surg Oncol 2003;1:25)

Additional references
Brucellosis

Definition / general
  • Due to Brucella abortus, melitensis or suis
  • Either occupational or food related (milk and cheese)
  • Fever, hepatosplenomegaly, rarely lymphadenopathy

Case reports
  • 22 year old woman with Kikuchi-Fujimoto necrotizing lymphadenitis associated with brucellosis (Sangre (Barc) 1992;37:201)
  • 43 year old man with B. melitensis and subsequent Kikuchi-Fujimoto disease (In Vivo 2003;17:51)

Diagnosis
  • Culture, PCR, serology

Microscopic (histologic) description
  • Follicular hyperplasia, clusters of epithelioid histiocytes that may form large noncaseating granulomas
  • Eosinophils, plasma cells, immunoblasts

Differential diagnosis
Coccidioides

Definition / general
  • Also called San Jaquin Valley Fever
  • Dimorphic fungus with distinct yeast and mold stages
  • Endemic to Lower Sonoran Desert (southwest US, Central and South America)
  • Usually self limiting but more severe disease in immunocompromised hosts

Case reports

Diagnosis
  • Culture (grows on all media)
  • Has enteroarthric conidia (alternating segments of hyphae undergo autolysis, while surviving segments form infective barrel shaped multinucleate arthroconidia)

Microscopic (histologic) description
  • Thick walled spherules 20 - 150 microns containing 3 - 5 micron endospores, surrounded by a giant cell granulomatous reaction

Additional references
Herpes simplex

Definition / general

Case reports

Microscopic (histologic) description
  • Well circumscribed necrosis, follicular and paracortical hyperplasia (Histopathology 1991;19:355)
  • Cells have intranuclear inclusions, particularly at edge of necrotic areas
  • Also marked immunoblasts, T cell hyperplasia

Microscopic (histologic) images

Contributed by Mark R. Wick, M.D.
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Herpes simplex lymphadenitis



Positive stains
  • HSV

Electron microscopy description
Histoplasmosis

Definition / general
  • May clinically mimic tuberculosis

Microscopic (histologic) description

Microscopic (histologic) images

Contributed by Mark R. Wick, M.D.
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H&E and GMS stain



Positive stains
Leishmania

Definition / general

Case reports

Microscopic (histologic) description
  • Granulomas with abundant plasma cells, focal fibrosis, variable necrosis, leishmanian amastigotes (by immunostain, Am J Clin Pathol 1994;102:11)

Cytology description
  • Polymorphous lymphocytes, histiocytes, plasma cells, giant cells and tingible body macrophages
  • Amastigote forms within histiocytes and multinucleated giant cells and extracellularly (Acta Cytol 2005;49:286)
Leprosy

Diagnosis
  • PCR, immunofluorescence

Case reports

Microscopic (histologic) description
  • Lepromatous leprosy exhibits large, pale, round histiocytes without granulomas and with no / rare necrosis

Microscopic (histologic) images

Images hosted on other servers:

Well developed germinal centers

Foamy histiocytes
contain M. leprae


Positive stains

Differential diagnosis
Lymphogranuloma venereum

Definition / general

Diagnosis
  • PCR
  • Previously Frei test (delayed hypersensitivity skin test using "lygranum" chlamydial antigen)

Treatment
  • Doxycycline for 21 days

Microscopic (histologic) description
  • Early: tiny necrotic foci with neutrophils
  • Late: stellate abscesses surrounded by pale epithelioid cells
  • Abscesses may merge and sinus tracts may develop
  • Macrophages may have organisms within vacuoles

Microscopic (histologic) images

Contributed by Mark R. Wick, M.D.
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Lymphogranuloma
venereum



Electron microscopy description
  • Elementary and reticulate bodies

Differential diagnosis
Measles

Definition / general
  • Live attenuated vaccine may cause regional lymphadenopathy
  • Measles associated lymphopenia may be due to apoptosis of uninfected lymphocytes (Arch Virol 2000;145:905)
  • Fatal measles cases in South African in 1976-1982 were associated with malnutrition; caused depletion of T cell zones (S Afr Med J 1985;68:858)

Case reports
  • 14 month old boy with familial immunodeficiency and necrotizing lymphadenitis with Warthin-Finkeldey type giant cells after measles vaccination (Ultrastruct Pathol 1980;1:243)

Microscopic (histologic) description
  • Polykaryocytes
  • In germinal centers, Warthin-Finkeldey giant cells have large nuclei and B cell markers
  • In interfollicular areas they have small hyperchromatic nuclei and T cell markers (Pathol Int 1994;44:442)

Microscopic (histologic) images

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Measles lymphadenitis

Microfilaria
See also related Breast topic

Definition / general
  • Filariasis is due to infection by threadlike nematodes of the family Filarioidea
  • Filarial infection can cause lymphedema of the limbs (elephantiasis), genital disease (hydrocele, chylocele and swelling of the scrotum and penis) and recurrent painful acute attacks (WHO: Lymphatic filariasis [Accessed 29 March 2021])

Essential features
  • Wuchereria bancrofti accounts for up to 90% of cases
  • Diagnosis is typically made by identifying microfilariae in peripheral blood smears
  • Rarely, microfilariae are coincidentally detected in FNAC in association with various inflammatory and neoplastic lesions
  • Wuchereria bancrofti can be identified by its sheath and multiple, coarse, discrete nuclei extending from head to tail except in the small terminal portion of the caudal end

Epidemiology
  • Major public health problem in India, China, Indonesia, Africa and the Far East

Pathophysiology
  • Wuchereria bancrofti accounts for up to 90% of cases
  • Adult worms lodge in the lymphatics, where females release larvae (microfilaria) which periodically circulate in the blood and are occasionally ingested by feeding mosquitoes
  • Microfilaria mature in the mosquitoes before becoming infective and are spread to new humans during mosquito feeding

Clinical features
  • Humans are the exclusive host of infection with W. bancrofti
  • Many infected individuals remain asymptomatic and serve as potential sources of infection
  • Virtually all infected people have subclinical lymphatic damage and up to 40% have kidney damage with proteinuria and hematuria

Diagnosis
  • Diagnosis is typically made by identifying microfilariae in peripheral blood smears
  • Rarely, microfilariae are coincidentally detected in FNAC in association with various inflammatory and neoplastic lesions (J Cytol 2010;27:78, J Cytol 2017;34:43)
  • Finding microfilaria in cytosmears is rare

Treatment
  • Treatment consists of multiple doses of albendazole and ivermectin to the entire at risk population, in addition to mosquito control

Microscopic (histologic) description
  • Wuchereria bancrofti can be identified by its sheath and multiple, coarse, discrete nuclei extending from head to tail except in the small terminal portion of the caudal end

Microscopic (histologic) images

Contributed by Sajna V.M. Kutty, M.D.

Case #446



Board review style question
Mycobacterial spindle cell pseudotumor

Definition / general

Case reports

Treatment
  • Antiretroviral therapy for HIV
  • Antibiotics

Microscopic (histologic) description
  • Nodes show partial / complete effacement by storiform pattern of bland spindle cells, some with vacuoles
  • Numerous vessels lined by plump endothelial cells, plasma cells and lymphocytes
  • No multinucleated tumor cells, no foamy histiocytes

Microscopic (histologic) images

AFIP images

Various images



Cytology description

Positive stains

Differential diagnosis
Parvovirus B19

Definition / general
  • In adults, parvovirus B19 infection is associated with fever (81%), arthralgia / myalgia (62%), skin rash (48%), general fatigue (43%), lymphadenopathy (38%) and edema (38%) (Intern Med 2002;41:295)
  • May be associated with hemophagocytic syndrome (Br J Haematol 1997;96:868)

Diagnosis
  • PCR
  • Immunohistochemistry

Case reports

Microscopic (histologic) description
  • Massive nodular histiocytic proliferation resembling Kikuchi disease with prominent apoptosis but no necrosis
  • One case showed florid reactive hyperplasia with paracortical expansion, neutrophils and hemophagocytosis (Pathol Int 1998;48:829)

Microscopic (histologic) images

Images hosted on other servers:

Prominent nodules of histiocytes

Tuberculosis
See also: Lung - nontumor chapter

Definition / general
  • Usually nodal involvement of cervical region (scrofula), often with draining sinus to skin
  • Generalized TB in AIDS cases at autopsy show thoracic or abdominal nodal involvement in almost all cases, although TB often not diagnosed prior to death (Arch Pathol Lab Med 2000;124:1267)
  • Needle biopsy of enlarged nodes may be helpful in smear negative, HIV+ patients with suspected TB (Int J Tuberc Lung Dis 2005;9:220)

Diagnosis

Case reports

Gross description
  • Large multinodular mass that resembles carcinoma with multiple foci of caseous necrosis

Gross images

Contributed by Mark R. Wick, M.D.

Tuberculous lymphadenitis



Images hosted on other servers:

Multinodular mass



Microscopic (histologic) description
  • Either multiple small epithelioid granulomas or huge epithelioid granulomas with prominent Langhans giant cells and central necrosis (J Clin Pathol 1988;41:93)

Microscopic (histologic) images

Contributed by Mark R. Wick, M.D.

Tuberculous lymphadenitis

Ziehl-Neelsen stain



Images hosted on other servers:

Granulomatous reaction

Noncaseous necrosis with prominent nuclear debris


Macrophages around foci of necrosis

With metastatic adenocarcinoma

Ziehl-Neelsen stain in HIV+ patient with TB

Tularemia

Definition / general

Diagnosis

Microscopic (histologic) description
  • Early: reactive changes
  • Second week: abscess with variable epithelioid cell reaction
  • Fourth week: caseous necrosis, diffuse lymphadenitis
  • Late: granulomatous reactions that may resemble TB
  • Often extracapsular inflammation (Arch Pathol Lab Med 1986;110:42)

Differential diagnosis
Whipple disease

Definition / general
  • Rare; due to infection by Tropheryma whipplei, present in soil and sewage but not animals
  • Typically affects farmers and outdoor workers
  • Symptoms include diarrhea, malabsorption, weight loss, fever, arthralgias; also occasional CNS and cardiac involvement
  • May cause marked enlargement of mesenteric and periaortic lymph nodes; enlargement of peripheral lymph nodes may occur early
  • Diagnosis requires massive involvement of node plus intense PAS+ staining (small aggregates of PAS+ macrophages are nonspecific) or PCR
  • Gram stain: gram+ bacteria

Case reports

Treatment
  • IV penicillin and streptomycin or third generalization cephalosporin for 10 - 14 days, plus cotrimoxazone for 1 year

Microscopic (histologic) description
  • Nodal architecture obscured by ill defined lipogranulomas
  • Involvement of sinuses by macrophages with foamy cytoplasm

Microscopic (histologic) images

Contributed by Mark R. Wick, M.D.

Various images

PAS stain

Warthin-Starry stain



Positive stains

Negative stains

Electron microscopy description
  • Rod-like organisms

Electron microscopy images

Images hosted on other servers:

Trilaminar cell wall



Molecular / cytogenetics description

Differential diagnosis
Yersinia pestis

Definition / general
  • Similar to Y. pseudotuberculosis

Clinical features

Diagnosis
  • Gram stain: gram negative, polymorphic, coccoid or ovoid mobile bacteria
  • PCR
  • Cultures

Case reports

Microscopic (histologic) description
  • Capsular thickening and edema
  • Immunoblasts and plasma cells in cortical and paracortical region
  • Large lymphocytes within sinuses, germinal center hyperplasia
  • No granulomas (unlike Y. pseudotuberculosis)
  • Depletion of lymphocytes, edema, necrosis, foamy macrophages
  • Bacteria may involve blood vessels

Positive stains
Yersinia pseudotuberculosis

Definition / general

Diagnosis
  • PCR
  • Cultures

Gross description
  • Inflammation of terminal ileum and cecum

Microscopic (histologic) description
  • Capsular thickening and edema
  • Granulomas with central necrosis and microabscesses
  • Immunoblasts and plasma cells in cortical and paracortical region, large lymphocytes within sinuses, germinal center hyperplasia

Additional references
Board review style question #1
Which statement regarding microfilarial infection is true

  1. Diagnosis is made by culture
  2. Infections are associated with exposure to animals
  3. Most patients have nonspecific symptoms
  4. Mosquito control is an important part of treatment
  5. Quarantine is an important component of treatment
Board review style answer #1
D. Mosquito control is an important part of treatment

Comment Here

Reference: Other infections
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