The "bruise" arose after the 20-month-old bumped his cheek on a piece of furniture 1 month ago. Can you identify the lesion?
A 20-month-old boy presents with an unusual bruise that arose after he bumped his face against his toy chest 4-5 weeks ago. The nodule is reddish-blue, very firm and feels as though it has several lumps within it. He has no other skin lesions. The only laboratory test performed is a CBC which reveals a normal differential and normal indices. The child is otherwise well.
What is your diagnosis?