title: Photo Quiz: An Unexpected Cause of Progressive Anal Mass.
authors.affiliation: Infectious Diseases Unit, University Hospital 12 de Octubre, Madrid, Spain lalueza@hotmail.com.
authors.forename: Antonio
authors.initials: A
authors.lastname: Lalueza
authors.affiliation: Department of Surgery, University Hospital 12 de Octubre, Madrid, Spain.
authors.forename: Félix
authors.initials: F
authors.lastname: Cambra
authors.affiliation: Department of Pathology, University Hospital 12 de Octubre, Madrid, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Urbanowicz
authors.affiliation: Infectious Diseases Unit, University Hospital 12 de Octubre, Madrid, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: San Juan
authors.affiliation: Department of Pathology, University Hospital 12 de Octubre, Madrid, Spain.
authors.forename: Guadalupe
authors.initials: G
authors.lastname: López-Alonso
authors.affiliation: Infectious Diseases Unit, University Hospital 12 de Octubre, Madrid, Spain.
authors.forename: José María
authors.initials: JM
authors.lastname: Aguado
mesh_terms: D001003:Anal Canal / Q000473:pathology*; D001004:Anus Diseases / Q000175:diagnosis* / Q000469:parasitology / Q000473:pathology*; D006651:Histocytochemistry; D006801:Humans; D007891:Leishmania / Q000302:isolation & purification*; D007898:Leishmaniasis, Visceral / Q000175:diagnosis* / Q000469:parasitology / Q000473:pathology*; D008297:Male; D008853:Microscopy