RT Book, Section A1 Mayeaux, E.J. A1 Usatine, Richard P. A2 Usatine, Richard P. A2 Sabella, Camille A2 Smith, Mindy Ann A2 Mayeaux, E.J. A2 Chumley, Heidi S. A2 Appachi, Elumalai SR Print(0) ID 1114877582 T1 Pigmented Nail Disorders T2 The Color Atlas of Pediatrics YR 2015 FD 2015 PB McGraw-Hill Education PP New York, NY SN 978-0-07-176701-9 LK accesspediatrics.mhmedical.com/content.aspx?aid=1114877582 RD 2024/03/28 AB A four-year-old boy presents with a newly pigmented line on his right thumb for 6 months. He already had one pigmented line on that same thumb since age one. His parents want to know if this pigmentation is dangerous. The child is otherwise healthy. On examination there are two longitudinal pigmented lines easily visible on the right thumbnail (Figure 161-1A). The boy is referred to a pediatric dermatologist. Examination with a dermatoscope shows the details of the many lines and confirms his concern for melanoma (Figure 161-1B). The concerns are expressed to the parents and the child is set up for a nail matrix biopsy with sedation. The differential diagnosis also includes a congenital melanocytic nevus that is growing.