title: Delayed reaction to "lead" pencil simulating melanoma.
abstract: A 74-year-old man had sustained a penetrating lead pencil injury to his right lower leg at the age of fifteen. A dark gray macule occurred that remained unchanged for fifty-eight years. An enlarging black nodule appeared in this area, simulating a melanoma, when the patient was seventy-three years old. Histologic examination revealed exogenous pigment and a foreign body reaction.
mesh_terms: D000368:Aged; D002244:Carbon; D003937:Diagnosis, Differential; D005549:Foreign-Body Reaction / Q000175:diagnosis*; D006108:Graphite; D006801:Humans; D008297:Male; D008545:Melanoma / Q000175:diagnosis* / Q000473:pathology; D012867:Skin / Q000473:pathology; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000473:pathology; D013997:Time Factors; D014950:Wounds, Penetrating / Q000150:complications*
chemical_list: D002244:Carbon; D006108:Graphite