Disseminated acanthamoebiasis presenting as lobular panniculitis with necrotizing vasculitis in a patient with AIDS

Background: Disseminated acanthamoebiasis is a rare entity, almost exclusively occurring in the immunocompromised host. Methods: We report an unusual case of a 35-year-old female with recurrent sinusitis and multiple skin nodules demonstrating a necrotizing panniculitis, shown to be due to disseminated acanthamoebiasis. Results: Histologic sections showed a neutrophilic lobular panniculitis with 20- to 30-μm trophozoites consistent with Acanthamoeba species. Conclusions: A review the literature shows that the histopathological presentation of acanthamoebiasis often eludes initial diagnostic attempts and that central nervous system (CNS) involvement is frequent and ultimately fatal. When amoebiasis is suspected, knowledge of the trophozoite and cyst forms may be helpful in distinguishing Acanthamoeba species from Entamoeba histolytica.