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A 36-year old HIV-positive man with AIDS presents with multiple red nodules distributed throughout his trunk and back.

Bacillary Angiomatosis
Medicine (Baltimore). 2016 Jul; 95(28): e4155.

Biopsy demonstrated vascular proliferation withint the dermis and numerous bacilli with Warthin-Starry staining. HHV-8 staining was negative. What is the likely diagnosis? Scroll down for answer.























bacillary angiomatosis


Bacillary angiomatosis is an infectious presentation of Bartonella henselae that is usually found in patients with advanced immunocompromise. The primary reservoir of B. henselae is cats. It presents as violascious lesions notable on biopsy for vascular proliferation; Warthin-Starry staining should be performed when bacillary angiomatosis is suspected as it may reveal dark staining clusters of microorganisms. It most often involves the skin but may also form in the respiratory tract, GI tract, bone, brain, and lymph nodes. Isolation of Bartonella is notoriously difficult; as such PCR is a powerful diagnostic tool. Differential diagnosis includes Kaposi’s sarcoma, pyogenic granuloma, and epithelioid hemangioma. Treatment is three months of doxycycline.


Medicine (Baltimore). 2016 Jul; 95(28): e4155.

Am J Surg Pathol. 1989;13(11):909.