Reminder: radiopacities from metal-containing substances.

A 17-month-old boy with a toed-out left lower extremity was presented for evaluation. Before coming to the doctor, the mother had applied a zinc oxide lotion to treat a simple diaper rash in the groin. The radiologist did not remove the boy's diaper for the radiographic examination and so did not notice the lotion. The first radiograph showed what looked like multiple soft-tissue calcifications in the groin, but the radiopacities had been produced by the zinc oxide. This case serves as a reminder to be aware that metal-containing substances both on and in the body can produce radiopacities.