Lymph nodes & spleen, nonlymphoma
Lymph nodes-infectious / parasitic disorders
Bacillary angiomatosis

Topic Completed: 1 July 2013

Minor changes: 18 December 2020

Revised: 1 February 2019, last major update July 2013

Copyright: 2003-2021,, Inc.

PubMed Search: Bacillary angiomatosis [title] lymph nodes

Page views in 2020: 909
Page views in 2021 to date: 35
Cite this page: DePond W. Bacillary angiomatosis. website. Accessed January 18th, 2021.
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
  • PCR
Case reports
  • 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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Warthin-Starry stain

Images hosted on other servers:
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AIDS patients

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Figures 1/2: confluent nodular areas with proliferating vessels
3: solid clusters of plump endothelial cells without lumina;
inset: granular and amorphous material
4: Southern blot with B henselae probe (specimen-tubes 1,3,5,7;
positive control-tube 9)

Differential diagnosis
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Image 01 Image 02