Skin nonmelanocytic tumor
Vascular tumors
Bacillary angiomatosis


Topic Completed: 1 January 2017

Minor changes: 14 October 2020

Copyright: 2001-2020, PathologyOutlines.com, Inc.

PubMed search: bacillary angiomatosis [title] skin

Joel Tjarks, M.D.
Sara C. Shalin, M.D., Ph.D.
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Cite this page: Tjarks J, Shalin S. Bacillary angiomatosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumornonmelanocyticbacillaryangiomatosis.html. Accessed October 21st, 2020.
Definition / general
  • Reactive vascular proliferation due to infection by Bartonella henselae or Bartonella quintana
  • Most commonly affects immunocompromised individuals (especially those with HIV)
Essential features
  • Lobular proliferation of capillaries with ectatic vessels lined by prominent endothelial cells
  • Neutrophils, lymphocytes and histiocytes are frequently present
  • Purplish grey bacterial colonies may be seen
Epidemiology
  • May affect adults and children
  • Most commonly affects immunocompromised individuals
Sites
  • Can occur in any cutaneous site
  • Rarely occurs in mucosa or internal organs
Etiology
  • B. Henselae is acquired via cat scratch or bite in 2/3 of cases
Clinical features
  • Red, smooth papules and nodules which are widely distributed
  • May mimic Kaposi sarcoma and pyogenic granuloma clinically
Laboratory
  • PCR and IHC may be helpful in identifying organisms
Case reports
Treatment
  • Antibiotics - typically doxycycline
Clinical images

Images hosted on other servers:

Papules on face, chest, abdomen and back; mass lesion on face

Exophytic lesion on neck

Small, cherry angiomata-like lesions and nodules

Microscopic (histologic) description
  • Lobular proliferation of capillaries with ectatic vessels lined by prominent endothelial cells in edematous stroma
  • Neutrophils, lymphocytes and histiocytes are frequently present
  • Purplish grey bacterial colonies may be seen, especially near neutrophils
  • Peripheral collarette may be seen (low power histologic image mimics pyogenic granuloma)
  • Warthin-Starry special stain will highlight Bartonella organisms
Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Dr. Tammie Ferringer:

Bacillary angiomatosis profile



Contributed by Dr. Nathan Lee:

Bacillary angiomatosis



Contributed by Dr. Mark R. Wick:

Breast skin

Steiner stain, breast

Positive stains
Differential diagnosis
  • Kaposi sarcoma: spindled vascular proliferation with slit-like vascular spaces, plasma cells, HHV8 positive, lacks purplish grey bacterial colonies
  • Pyogenic granuloma: lobular proliferation of capillaries, but typically somewhat less inflamed (unless ulcerated) and no purplish grey bacterial colonies
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