Bacillary Angiomatosis Masquerading as Kaposi’s Sarcoma in East Africa

Abstract

Background Bacillary angiomatosis (BA) is a rare manifestation of infection caused by Bartonella species, which leads to vasoproliferative lesions of skin and other organs. Bacillary angiomatosis affects individuals with advanced HIV disease or other immunocompromised individuals. In sub-Saharan Africa, despite the high prevalence of HIV infection and documentation of the causative Bartonella species in humans, mammalian hosts, and arthropod vectors, BA has only rarely been described. Methods Three adult patients from Uganda and Kenya with deep purple dome-shaped papules or nodules of the skin underwent punch biopsies for histopathologic diagnosis. The biopsies of all 3 patients were sent to a local pathologist as well as to a dermatopathologist at the University of California, San Francisco. Results All 3 patients were clinically suspected to have Kaposi’s sarcoma (KS), and local pathologists had interpreted the lesions as KS in 2 of the cases and nonspecific inflammation in the third. Histologic examination by dermatopathologists in the United States revealed nodular dermal proliferations of irregular capillaries lined by spindled to epithelioid endothelial cells. The surrounding stroma contained a mixed inflammatory infiltrate with lymphocytes, eosinophils, and neutrophils. Extracellular deposits of pale amphophilic granular material were noted in the surrounding stroma. A Warthin-Starry stain highlighted clumps of bacilli, confirming the diagnosis of BA. Conclusions These 3 cases, to our knowledge, are the first reports of BA in East Africa in the biomedical literature. Each had been originally incorrectly diagnosed as KS. We speculate BA is underdiagnosed and underreported in resource-poor regions, such as sub- Saharan Africa, that have high endemic rates of HIV infection.

Kaposi sarcoma

“…Although this is straightforward in resource-rich settings, the process can be challenging in resource-limited settings, such as in Africa, where KS is most common, and macroscopic clinical visualization is often the only available means for diagnosing KS. Indeed, in one study from East Africa, visual diagnosis alone had only 80% positive predictive value for KS 150 ; some patients were falsely diagnosed with KS, giving them an indication for needless chemotherapy and missing the correct, often easily treatable, diagnoses (for example, bacillary angiomatosis) 151 . To remedy this, several efforts have been aimed at increasing the histologic diagnosis of KS, including task shifting the performance of biopsies to non-physicians 152 as well as teledermatology and telepathology 153 .…”

Bacillary Angiomatosis Mimicking Pyogenic Granuloma

“…The clinical manifestations of Bartonella henselae infection vary in patients with immunocompromised status. So, a differential diagnosis of malignant neoplasms such as Kaposi sarcoma or angiosarcoma/benign conditions such as pyogenic granuloma and angiolymphoid hyperplasia with eosinophilia should be considered [13].…”

Steroid-exacerbated HIV-associated cutaneous Kaposi’s sarcoma immune reconstitution inflammatory syndrome: ‘Where a good intention turns bad’

“…3 However, other conditions may mimic KS, such as bacillary angiomatosis, warranting confirmatory biopsy procedures. 4–6 Spindle-shaped cells with slit-like vascular channels is the pathognomonic histologic finding. 6…”