Bacillary angiomatosis in a HIV-negative patient.

Bacillary angiomatosis is a rare cutaneous manifestation caused by infection with Bartonella henselae that is most often seen in immunocompromised individuals, particularly those with HIV. We present an HIV-negative elderly man with bacillary angiomatosis with unexplained pancytopenia. The patient presented with a solitary, pedunculated, vascular nodule on his right forearm, and a shave biopsy was performed to rule out metastatic cancer. Biopsy results were consistent with bacillary angiomatosis, which was confirmed with polymerase chain reaction. Further evaluation revealed severely low CD4 counts in our patient, despite two negative HIV tests and lack of immunosuppressive drugs or conditions besides cytopenia. He eventually met criteria for idiopathic CD4 lymphocytopenia and was treated with doxycycline for coverage of possible disseminated infection. This case demonstrates the importance of keeping bacillary angiomatosis in the differential diagnosis in patients presenting with pedunculated angioproliferative lesions, regardless of HIV status.