Histopathology of bacillary angiomatosis of lymph node

Bacillary angiomatosis, a recently characterized pseudoneoplastic vascular proliferation caused by a bacterium identical or related to the cat-scratch disease bacillus, usually presents as cutaneous lesions. We report the histologic findings of this disease involving the lymph nodes of two immunocompromised patients. The lymph nodes showed patchy involvement by coalescent nodules of proliferated blood vessels lined by plump endothelial cells with pale cytoplasm. There were foci exhibiting mild to moderate nuclear atypia. Although neutrophil infiltration was prominent in one case, it was minimal in the other. The interstitium was formed by pink-staining material in hematoxylin-eosin-stained sections, and this proved to be aggregated bacilli on Warthin-Starry stain. Recognition of this potentially fatal disease is important because it is curable with antibiotics.