title: Perianal ulcer.
authors.forename: J F
authors.initials: JF
authors.lastname: Meis
authors.forename: H
authors.initials: H
authors.lastname: van Goor
authors.forename: P E
authors.initials: PE
authors.lastname: Verweij
mesh_terms: D003424:Crohn Disease / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005401:Fissure in Ano / Q000175:diagnosis* / Q000382:microbiology; D006660:Histoplasmosis / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged