Nodular Skin Lesions in an Immunocompromised Patient

Diagnosis: Disseminated amebiasis (Acanthamoeba species). Our patient was an immunocompromised individual who died after developing a progressive meningoencephalitis with associated brain lesions (Figure 1) and concurrent nodular skin lesions (Figure 2). Histopathology from the cutaneous lesions revealed numerous cysts and trophozoites (Figure 3), which were pathologically consistent with free-living amoebae (either Balamuthia species or Acanthamoeba species). Indirect immunofluorescence testing was performed by the Centers for Disease Control and Prevention (CDC), and was positive for Acanthamoeba species and negative for Balamuthia mandrillaris. Cultures of the cerebrospinal fluid (CSF) were without growth; however, after the pathology findings from the skin biopsy, remaining CSF was sent to the CDC and found to be positive by polymerase chain reaction (PCR) for Acanthamoeba species. These findings are consistent with a diagnosis of disseminated acanthamebiasis. The most common clinical presentation of Acanthamoeba species is a nonopportunistic keratitis, usually in contact lens wearers. Other human infections with this free-living amoeba are rare and include sinus infections, skin manifestations, and central nervous system (CNS) involvement, most often granulomatous amoebic encephalitis (GAE). Typically, these syndromes affect the immunocompromised host, often patients with human immunodeficiency virus/AIDS or transplant recipients. Cutaneous acanthamebiasis can present as either ulcerative or nodular, and is often a reflection of disseminated disease [1]. GAE is a slowly progressive meningoencephalitis, and is fatal with few exceptions. Symptoms are typical for meningoencephalitis and include alteration in mental status, meningismus, headache, seizure, and photophobia [2]. Figure 1. A 3-cm hypodense lesion in the left temporal lobe. Figure 2. Several discrete 2to 3-cm erythematous nodules are present in a linear arrangement over the left thigh.