title: Disseminated Acanthamoeba Infection Presenting With Cutaneous Lesions in an Immunocompromised Patient: A Case Report, Review of Histomorphologic Findings, and Potential Diagnostic Pitfalls.
abstract: OBJECTIVE
  Free-living amoebas are exceedingly rare causes of cutaneous infections and present unique diagnostic and therapeutic challenges. We describe a case of disseminated acanthamoebiasis with cutaneous manifestations and summarize additional diagnostic, prognostic, and therapeutic highlights.
  
  
  METHODS
  A 58-year-old man with relapsed chronic lymphocytic leukemia had several weeks of progressive, painful ulcerations on the forehead, arms, abdomen, and thighs. A biopsy was performed for histopathologic evaluation.
  
  
  RESULTS
  The biopsy specimen showed inflammatory infiltrate with abscess formation involving the epidermis, dermis, and subcutis. Scattered cells showed nuclei with a prominent central karyosome, dispersed chromatin, and either abundant foamy basophilic cytoplasm or two well-demarcated cytoplasmic walls. Acanthamoeba species was confirmed by polymerase chain reaction from the formalin-fixed, paraffin-embedded tissue.
  
  
  CONCLUSIONS
  Cutaneous lesions from acanthamoebiasis are exceptionally rare but should be included in the differential diagnosis of necrotic cutaneous lesions in immunocompromised patients. Although infrequently encountered, pathologists need to be aware of the morphologic features of free-living amoebas. Immunohistochemical and molecular studies can confirm the diagnosis. Multiagent treatment regimens, when initiated empirically, have been more successful than single-agent regimens, but infections involving the central nervous system are almost universally fatal.
authors.affiliation: From the Departments of Pathology and Laboratory Medicine anniemorrisonmd@gmail.com.
authors.forename: Annie O
authors.initials: AO
authors.lastname: Morrison
authors.affiliation: From the Departments of Pathology and Laboratory Medicine Dermatology, Emory University, Atlanta, GA.
authors.forename: Robert
authors.initials: R
authors.lastname: Morris
authors.affiliation: Department of Dermatology, Louisiana State University, Baton Rouge.
authors.forename: Amie
authors.initials: A
authors.lastname: Shannon
authors.affiliation: Department of Pathology, Alegent Creighton Health, Omaha, NE.
authors.forename: Scott R
authors.initials: SR
authors.lastname: Lauer
authors.affiliation: From the Departments of Pathology and Laboratory Medicine.
authors.forename: Jeannette
authors.initials: J
authors.lastname: Guarner
authors.affiliation: From the Departments of Pathology and Laboratory Medicine.
authors.forename: Colleen S
authors.initials: CS
authors.lastname: Kraft
mesh_terms: D000048:Acanthamoeba / Q000302:isolation & purification*; D000562:Amebiasis / Q000150:complications / Q000175:diagnosis*; D001132:Arm / Q000473:pathology; D001706:Biopsy; D005546:Forehead / Q000473:pathology; D006801:Humans; D016867:Immunocompromised Host; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000150:complications / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009894:Opportunistic Infections; D011379:Prognosis; D012867:Skin / Q000473:pathology*
keywords: Acanthamoeba; Acanthamoebiasis; Amoebiasis; Amoebic infection; Cutaneous amoeba; Opportunistic infection