Question 1:
A 17-year-old Caucasian male presented with a solitary vegetating 1.2 cm lesion suspected of being an ingrown toenail of the left foot. Histopathologic evaluation of the lesion revealed the following features (Figures 1, 2, 3 and 4) and immunohistochemical findings (Figures 5, 6, 7 and 8).
Click this image to view the virtual slide.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5 AE1/AE3
Figure 6 CD31
Figure 7 CD34
Figure 8 INI1
Which of the following is the best diagnosis?