title: A 12-year-old girl with an enlarging nontender nodule on the arm.
authors.affiliation: Children's Memorial Medical Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60614, USA. awagner@northwestern.edu
authors.forename: Annette M
authors.initials: AM
authors.lastname: Wagner
mesh_terms: D001132:Arm; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006201:Hair Diseases / Q000175:diagnosis*; D006801:Humans; D018296:Pilomatrixoma / Q000175:diagnosis*; D012878:Skin Neoplasms / Q000175:diagnosis*