A thriving boy was brought to the office 3 weeks after his first birthday. His mother reported that there was "something wrong with his knee." On visual examination, the knee appeared perfectly normal. On palpation, however, a 4-cm linear induration was evident over the knee fat pad, just medial and distal to the patella. It appeared soft, crepitant, and associated with the skin. No tenderness was noted on palpation; the infant did not object to palpation of this density any more than to auscultation, otoscopy, or anthropometric measurements. No erythema, ecchymosis, or signs of trauma were evident near the lesion. The only possibly relevant history was that the child had spent his birthday at his grandmother's home in the Ukraine a month earlier. He was constantly with his mother during that time, and no trauma was ever reported.