A 55-year-old man is referred for evaluation of a lesion on his leg, which he first noted approximately 2 months prior. What is the most likely diagnosis?

A 72-year-old man with persistent pain in his left shoulder and upper arm develops a blister and reddening skin after using a heating pad for pain management.

A 5-year-old Hispanic girl is evaluated for a growth on her neck. Her parents state that the lesion has been present since birth and continues to increase in size proportionate to her growth.